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Tandy 6000 HD Service Manual

Summary of 6000 HD

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    Tandy® service manual tandy 6000/6000 hd catalog number 26-6021/2 custom manufactured for radio shack, a division of tandy corporation 26 -6 02 1/2.

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    Ta n d y computer products service manual tandy® 6000/6000-hd catalog number 26-6021/2.

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    Tan d y computer products tandy® 6000/6000-hd service manual copyright 1985 tandy corporation all rights reserved reproduction or use, without express written permission from tandy corporation, of any portion of this manual is prohibited. While reasonable efforts have been taken in the preparation o...

  • Page 5

    Tan d y computer products contents page n o . 1/ introduction ........................................... 1 2/ technical specifications .............................. 7 3/ disassembly/assembly procedures ...................... 9 4/ adjustments ........................................... 19 5/ cablin...

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    Tandy computer products list of figures number description page no. 1-1 major assemblies, tandy 6000/6000-hd ......... 2 3-1 cover/bezel assembly mounting screws ........ 10 3-2 electronics module assembly .................. 15 4-1 adjustments ................................... 20 5-1 cable interco...

  • Page 7

    Tan d y computer products 8-1 exploded view, base assembly ............... 244 8-2 exploded view, card cage, chassis, and power s u p p l y ............................. 247 8-3 exploded view, floppy disk drive ........... 249 8-4 exploded view, hard disk drive assembly .... 251 8-5 exploded view, b...

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    Tandy computer products.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 1/ introduction the tandy 6000/6000-hd microcomputer is a powerful disk-based desk-top business computer with many advanced features. These features include portable sof...

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    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- figure 1-1. Major assemblies, tandy 6000/6000-hd - 2 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- a simplified exploded view of the tandy 6000/6000-hd (figure 1-1) helps locate major sub-assemblies as they are described in the following paragraphs. Disassembly proced...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 1.3 reset switch/power-on indicator module the reset switch/power-on indicator module is mounted to the drive support structure and consists of the power on/off indicato...

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    Service manual tandy 6000/6000-hd tan d y computer products --------------------------------------------------------------------- caution the cables between the video/keyboard interface pcb, power supply and the monitor pcb are short and may be damaged if care is not exercised during their removal. ...

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    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 6 -.

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    Service manual tandy 6000/6000-hd ta n d y computer products ---------------------------------------------------------------------- 2/ technical specifications 2.1 physical characteristics 2.1.1 case/bezel/base assembly width 21.0 inches (53.3 cm) height 13.5 inches (34.3 cm) depth 20.5 inches (52.1...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- parallel interface connects to a line printer via the 34-pin connector on the back of the display console. See section 5, cable wiring/pin designations. Outputs 8 data b...

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    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- 3/ disassembly/assembly procedures the tandy 6000 microcomputer is designed for table-top operation. Dimensions of the main housing assembly and the keyboard assembly ...

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    Service manual tandy 6000/6000-hd tandy computer products ---------------------------------------------------------------------- figure 3-1. Cover assembly and bezel assembly mounting screws - 10 -.

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    Service manual tandy 6000/6000-hd t a n d y computer products --------------------------------------------------------------------- 3.2 bezel/crt assembly removal 1. Loosen the three (3) screws at the front of the unit that attach the bezel/crt assembly to the base assembly. See figure 3-1, which sh...

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    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tandy computer products ---------------------------------------------------------------------- 5. Remove the two left mounting nuts and washers that attach the crt monitor pcb bracket to the bezel...

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    Service manual tandy 6000/6000-hd tan d y computer products -------------------------------------------------------------------- 3.5 crt monitor pcb 1. Remove the 10 pin edge connector. 2. Remove the four (4) screws which attach the crt monitor pcb to the bracket. 3. Re-assemble in the reverse order...

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    Service manual tandy 6000/6000-hd tandy computer products ---------------------------------------------------------------------- 9. If a drive is to be replaced, remove the front bezel by removing the mounting screws (two at the top and two at the bottom front l i p ) . 10. Remove the hard disk driv...

  • Page 23

    Service manual tandy 6000/6000-hd —--------------------------------------------------------------- tan d y computer products — — ------------------------------------------------------------- figure 3-2. Electronics module assembly - 15 -.

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    Service manual tandy 6000/6000-hd tandy computer products ---------------------------------------------------------------------- 8. Disconnect the grounds from the two cables attached to the video/keyboard interface pcb on the grounding lugs of the rh board retainer. 9. Remove the pc board retainers...

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    Service manual tandy 6000/6000-hd tan d y computer products --------------------------------------------------------------------- 17. Remove the mother board assembly from the electronics module chassis. 18. Remove the power supply assembly from the electronics module chassis by removing two screws ...

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    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tandy computer products ---------------------------------------------------------------------- 3.8 keyboard the keyboard assembly is a separate assembly that is attached to the main computer unit...

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    Service manual tandy 6000/6000-hd ta n d y computer products --------------------------------------------------------------------- 4/ adjustments the only adjustments on the tandy 6000/6000-hd microcomputer are associated with the floppy disk drive interface and are required to be made only if disk ...

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    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tandy computer products ---------------------------------------------------------------------- figure 4-1. Adjustments - 20 -.

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    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- 7. Adjust r50 (located just to the right of c61 looking from the rear of the unit) for a positive pulse width of 200 nanoseconds. 8. Connect the scope lead to test poi...

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    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 22 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 5/ cabling diagrams/pin designations contained in this section is a cable block diagram of the tandy 6000/6000-hd system, and pin designations of all the connectors of t...

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    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 24 -.

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    Service manual tandy 6000/6000-hd ta n d y computer products figure 5-2. Cable wiring/cable location - floppy disk drives version 1 - 25 -.

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    Service manual tandy 6000/6000-hd ta n d y computer products ---------------------------------------------------------------------- figure 5-3. Cable wiring/cable location - hard disk drives version 1 - 27 -.

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    Service manual tandy 6000/6000-hd ta n d y computer products ---------------------------------------------------------------------- figure 5-4. Cable wiring/cable location - floppy disk drives version 2 - 29 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- figure 5-5. Cable wiring/cable location - hard disk drives version 2 - 31 -.

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    Cable assembly 8000876, rs-232 serial interface service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products --------------------------------------------------------------------- main pcb connector pl/jl rear input channel a pin n...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- figure 5-6. Rs-232 serial interface cable figure 5-7. Line printer/parallel output cable - 34 -.

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    Cable assembly 6000877, line printer/parallel output wiring for this cable is pin to pin from one connector to the o t h e r . Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ------------------------------------------...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- cable assembly 6000878, fdc to internal drive wiring is pin to pin from one connector to the other. Main pcb p3/j3 to floppy diskette drive(s) pin name description 2 loc...

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    Cable assembly 6000879, video/keyboard pcb to keyboard service manual tandy 6000/6000-hd ---------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- video/keyboard interface p2/j2 keyboard re...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- cable assembly 6000880, dc power to system this cable supplies dc power from the power supply to the disk drives, the crt monitor pcb, and the mother board. It also supp...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- cable assembly 6000885, ac input this cable assembly provides switched ac input from the rear connector panel/fan support of the tandy 6000/6000-hd to the power supply a...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- cable assembly 6000887, i/o processor board to sound board this cable assembly interconnects the i/o processor pcb to the sound board located at the left front corner of...

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    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- harness assembly 6000888, video the video harness contains the wiring that supplies +12 volts to the video monitor assembly, wiring to the brightness and contrast cont...

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    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- harness assembly 6008046, fan power the fan harness consists of a twisted pair that picks up ac pow...

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    Service manual tandy 6000/6000-hd ----------------------------------------------------------------------- tandy computer products ----------------------------------------------------------------------- pin designations, i/o processor board jo, and all mother board connector positions this connector ...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- pin designations board connector (con't) i/o processor board jo, and all mother positions pin signal description 41 xferrq dma transfer request (in) 42 kbirq* keyboard i...

  • Page 49

    Pin designations, i/o processor board jl service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- pin signal description 1 bdl* data bit 1 inverted (input/o...

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    Service manual tandy 6000/6000-hd tan d y computer products --------------------------------------------------------------------- 48 ba20* address bit 20 inverted (output) 49 ba23* address bit 23 inverted (output) 50 ba22* address bit 22 inverted (output) pin designations, i/o processor board j2 pin...

  • Page 51

    Service manual tandy 6000/6000-hd tan d y computer products -------------------------------------------------------------------- 6/ troubleshooting procedures 6.1 tandy 6000/6000-hd i/o processor system this section of the manual will guide service personnel through the system checkout procedure. Th...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 4. Check rom integrity by calculating checksum and comparing it against a value in the rom. If it matches, continue. If there is a mismatch, the unit will print "boot er...

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    Service manual tandy 6000/6000-hd t a n d y computer products --------------------------------------------------------------------- if everything is in order, then the controller is directed to read data from track 0 and place it in the ram . 1. If a "record" is not found (no properly formatted data...

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    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- does not exist or is bad, the loading process may not be completed and no error messages will be displayed. The machine "hangs up" with "loading" message in the upper ...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- test procedures the following is a list of software routines that will thoroughly test the i/o processor system. 1. System - version dated 11/29/1982, tests sio (serial ...

  • Page 56

    Service manual tandy 6000/6000-hd tandy computer products ---------------------------------------------------------------------- 6.2 tandy 6000/6000-hd cpu and 512k/1 meg memory board in order to isolate trouble in the tandy 6000/6000-hd boards, run all current model ii diagnostics. If any failures ...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- run diagnostics condition possible fault recommended action 6000/6000-hd interrupt test test locked up on software in­ terrupt interrupt circuit check interrupt controll...

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    Service manual tandy 6000/6000-hd t an d y computer products ---------------------------------------------------------------------- run diagnostics condition possible fault recommended action 6000/6000-hd offset limit test random errors i/o decoding and strobes check i/o and strobe circuit mother bo...

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    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- 7/ theory of operation 7.1 mother board the mother board contains seven receptacles into which optional boards for the tandy 6000/6000-hd are plugged. The connector re...

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    Service manual tan d y computer products tandy 6000/6000-hd component location, mother board 8897701 - 56 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, mother board 8897701, component side - 57 -.

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    Service manual tandy 6000/6000-hd t an d y computer products ---------------------------------------------------------------------- circuit trace, mother board 8897701, solder side - 58 -.

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    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- t a n d y computer products ---------------------------------------------------------------------- parts list, mother board, 8897701 ref no. Description part no. --- pcb, mother board 8709318 capa...

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    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- - 60 -.

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    Service manual tandy 6000/6000-hd t an d y computer products ---------------------------------------------------------------------- 7.2 mc68000 cpu board the theory of operation for the mc68000 board has been divided into several major sections, each corresponding to a logical unit of lsi, msi, and ...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- the active-high state of dbtr enables the data drivers. It follows, therefore, that the data receivers are disabled when: a read or write is in progress from the interru...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- the bus as* (bas*) is a delayed as* which is required to allow the extra time needed for address checking of the memory management unit. As* is delayed through 4 74f32s ...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- ipll* is pulled high and iplo*, ipl2* are tied together which only allows level 5 to be active. For more details on interrupt operation, see paragraph 7.2.2 interrupt lo...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- halt* is also a bidirectional signal. When the z80a i/o port latch asserts halt*, the mc68000 cpu will stop at the end of the current bus cycle. If halt* is asserted by ...

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    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ interrupt request inputs table 7-1 lists, in order from the highest to the lowest priority, the interrupt inputs implemented in the mc68000 subsystem. For more informati...

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    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- interrupt description vector location c0nt4* initiated by the z80a 234h c0nt5 * initiated by the z...

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    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ additionally, two control ports must be initialized to determine the addresses involved and the mode of the t r a nsfer. The two ports are described in the tables and te...

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    Service manual tandy 6000/6000-hd t a n d y computer products --------------------------------------------------------------------- two modes are available for transferring data between the mc68000 and the z80a memory. These are the byte mode and the burst mode which are controlled by bit 0 of the t...

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    Service manual tandy 6000/6000-hd ! Tan d y computer products ——_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ f i g u r e 7 - 1 . Read and write cycle timing - 70 -.

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    Service manual _ __ tandy 6000/6000-hd ■ ------------------— --------------------------- --------------- tan d y computer products -------— _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ f i g u r e 7 - 2 . Write cycle timing - 71 -.

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    Service manual tandy 6000/6000-hd ■ -------- — ---------- tan d y computer p r o d u c t s ----------------------------------—_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ figure 7-3. Read cycle timing.

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    Service manual tan d y computer products tandy 6000/6000-hd figure 7-4. Refresh cycle timing of 68000 - 73 -.

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    Service manual tandy 6000/6000-hd ta n o y computer products ---------------------------------------------------------------------- details of control outputs (port odeh) 7.2.4 memory management circuitry a fast memory management scheme provides two sets of offset and limit registers. The offset and...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- write protection for the memory outside a user's partition is provided. Accesses outside of the user's defined partition result in the generation of a bus error exceptio...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- the source of the user extent address is selected by a23 and the signal mma (memory management active) determines which set of buffers (u31 or u30) drive the address bus...

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    Service manual tandy 6000/6000-hd t a n d y computer products --------------------------------------------------------------------- the sources for the four levels are refresh request (refrq*), bus request 2 (br2*), bus request 1 (brl*), and bus request 0 (bro*), with refrq* having the highest prior...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- figure 7-5. Bus arbitration circuit timing 7.2.6 data transfer acknowledge logic data transfer acknowledge (dtack*) is the asynchronous handshake signal used by memory a...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- if rip* is asserted, an interrupt acknowledge cycle is in progress and the interrupt vector data is valid from the interrupt controller chip u 1 5 . Iodtack* and rip* ar...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 7.2.7 mc68000 i/o decoding and strobes the i/o devices in the mc68000 subsystem are memory-mapped and consist of the: interrupt controller chip memory management registe...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- address function 7800d0 interrupt controller data register 7800d1 interrupt controller command register 7800d2 limit register two 7800d3 offset register two 7800d4 limit...

  • Page 86

    Table 7-3 outlines the memory map of the mc68000 subsystem: service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products -------------------------------------------------------------------- system ram table 7-3. Memory map of the ...

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    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- 7.2.9 refresh logic the refresh logic provides the necessary timing and control for generating the ...

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    Service manual tan d y computer products - tandy 6000/6000-hd - 84 - figure 7-8. Timing for refresh logic 7.2.10 cpu pal pin assignments and equations pal 16r4 (u48) pin assignments: 8 mhz 2 / srw ka19 5 6 vm2ad /as /reset gnd /e 12 /iorq /wr /b /c /d /rd /dtack vcc equations: if (vcc) dtack = / b *...

  • Page 89

    Service manual tandy 6000/6000-hd ta n d y computer products ---------------------------------------------------------------------- - 85 - b := /b * c * d * as * vm2ad * ka19 */reset + b * as * vm2ad * ka19 */reset wr := /b */c * as * vm2ad * ka19 * srw */reset + /b * c */d * as * vm2ad * ka19 * srw...

  • Page 90

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------— if (vcc) per = /bper pal 16r6a (u36) pin assignments: 8mhz 4mhz addval / zrd /refrq zao /bgl /dtack /memsel gnd /e burst /lds /uds /as /brl /bgen /rw /wait vcc equations: brl ...

  • Page 91

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- pal 16l8 (u40) pin assignments: ib 1c id refrsh refgl mode reset 2a 2b gnd 2c rfqtr /xo /xi /x2 /refrqclr /reftr 18 19 vcc equations: if(vcc) refrqclr = /reset* x2*/xl*/...

  • Page 92

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- component layout, mc68000 cpu board 8709573 - 88 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, mc68000 cpu board 8709573, component side.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, mc68000 cpu board 8709573, layer 2 - 90 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, mc68000 cpu board 8709573, layer 3 - 91 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, mc68000 cpu board 8709573, solder side - 92 -.

  • Page 97

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tandy computer products ------------------------------------------------------------------------ parts list, mc68000 cpu board, 8898855 ref no. Description part no. Pc board, cpu (rev a) 8709573 c...

  • Page 98

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- parts list, mc68000 cpu board, 8898855 ref no. Description part no. Resistors r17,r18 resistor, 4....

  • Page 99

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- parts list, mc68000 cpu board, 8898855 - 95 - ref no. Description part no. Intergrated circuits u3...

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    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 96 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- schematic, mc68000 cpu board, 8000247, page 1 or 3 - 97 -.

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- schematic, mc68000 cpu board, 8000247, page 2 or 3 - 99 -.

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    Service manual tandy 6000/6000-hd tan d y computer products --------------------------------------------------— _ _ ... — schematic, mc68000 cpu board, 8000247, page 3 or 3 - 101 -.

  • Page 104

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 7.3 memory board the tandy 6000/6000-hd memory board is a random access memory (ram) with a total capacity of 512k words (1 meg bytes) of data with optional byte parity ...

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    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- two particulars of dynamic rams are address multiplexing and refresh. There are 16 address lines required to access 64k drams and 18 address lines are required for 256k ...

  • Page 106

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- address lines al7 and a19 are optionally jump connected to the select input of u24 (74f158). This s...

  • Page 107

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- taps, 0, 140, and 180 of the delay line are used to generate bdtack*. Each tap after 0 will insert 2 wait states in the memory cycle to enable the use of slower drams....

  • Page 108

    Service manual tandy 6000/6000-hd tan d y computer products --------- —_ _ _ _ _ si (b18) (bl9)(b22) (b20) (b21 1 2 3 4 5 6 7 8 disable board x 0 x x x x x x 000000-03ffff x 1 0 x 0 0 0 0 040000-07ffff x 1 1 x 0 0 0 0 080000-0bffff x 1 0 x 1 0 0 0 0c0000-0fffff x 1 1 x 1 0 0 0 100000-13ffff x 1 0 x ...

  • Page 109

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- si (ba19) (ba22) (ba20) (ba21) 1 2 3 4 5 6 7 8 disable board x 0 x x x x x x 000000-07ffff x 1 x x 0 0 0 0 080000-0fffff x 1 x x 1 0 0 0 100000-17ffff x 1 x x 0 0 1 0 18...

  • Page 110

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 7.3.4 parity there are two parity circuits: input parity generators output parity checkers since there is byte parity, there is one parity bit for each byte. When data i...

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    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 110 -.

  • Page 112

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- component layout, 512k memory board - ill -.

  • Page 113

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- circuit trace, 512k memory board, component side - 112 -.

  • Page 114

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, 512k memory board, solder side - 113 -.

  • Page 115

    Service manual tan d y computer products tandy 6000/6000-hd - 114 - parts list, memory board, 8898854 ref no. Description part no. 6000 memory pc board rev. A 8709572 cable, 34 pos, int. Bus. Ext. Ii 8709391 --- cable, 50 pos, int. Bus. Ext. Ii 8709387 capacitors cl capacitor, 100 uf, 16v, mono-axia...

  • Page 116

    Service manual t an d y computer products tandy 6000/6000-hd parts list, memory board, 8898854 ref no. Description part no, integrated circuits u1 ic, 74f521, comparator 20-pin 8015521 u2-4 i c , 74s240, octal bus line driver, 20-pin 8015240 u5-8 ic,74als240, 20-pin 8025240 u9 ic, 74f244, octal buff...

  • Page 117

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 116 -.

  • Page 118

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- schematic, memory board, 8000229, page 1 of 2 - 117 -.

  • Page 119

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- schematic, memory board, 8000229, page 2 of 2 - 119 -.

  • Page 120

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 7.4 main logic board the main logic board is a complete eight-bit microprocessor system minus the video interface. The board features the z80a family of ics which provid...

  • Page 121

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- figure 7-9. I/o processor pcb block diagram - 1 2 2 -.

  • Page 122

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- comparator triggers when c3 is charged to generate a pulse of at least 100 microseconds. On a "manual" reset (front panel switch), a third comparator generates a pulse l...

  • Page 123

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 3. Buffers the cpu and dma are bus masters; they transmit the address and control signals onto the bus. Data is both transmitted and received by all entities on the bus....

  • Page 124

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- table 7-5. Input/output port map - 125 -.

  • Page 125

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- table 7-5. Input/output port map (con't) - 126 -.

  • Page 126

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 6. Interrupt control the cpu has two types of interrupts; maskable (int/) and non-maskable (nmi/). The non-maskable interrupt (bus name nmir q * ) is a method 1 type int...

  • Page 127

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- table 7-6. Memory map - 128 -.

  • Page 128

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- raco through rac5 are usable for 16k and 64k rams, both banks. Unique address combinations are 16rac6 (16k only, address bit 6), 64rac6 (64k only, address bit 6), l64rac...

  • Page 129

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- e i8 , ei9, e20 * rom size option ei8-e i9 ei9- e20 2 k x 8 rom a u = + 5 v 4 k * 8 rom all = all e 24,e 25,e 26 * floppy drive head load delay option e24-e25 e25-e26 no...

  • Page 130

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- e l, e 2 , e3 ram wait state options * e i- e 2 e 2 -e 3 wait state inserted during ml cycle no wait states e 4 , e5 * clock oscillator option e 4 -e 5 open 8 mhz osci...

  • Page 131

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- £50, e5i, £52 ram upper bank size option e50- e52 e 5i-e52 6 4 k s i z e i6 k size £53, e54, e55 options for serial channel a receive baud clock * e53- e54 e53-e55 int...

  • Page 132

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 4. Timing/control the timing/control subsection (schematic, sheet 5, 6) provides the necessary signals to access the memory and control the data transceiver. This circui...

  • Page 133

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- the rom timing seguence is simply (mreq*romsel) = romce/; chip select and (romsel*read) = romoe/; output enable. Refresh clears romsel during refresh. 5. Buffers the a...

  • Page 134

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- 3. Pio the pio is the z80a parallel input/output controller. It provides two parallel data interfac...

  • Page 135

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- 5. Sound the sound function is an oscillator of fixed frequency and variable duration under software control. The oscillator is located on a separate satellite board. ...

  • Page 136

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- pal 12l6 (ulo) pin assignments: read cao cal ca2 ca3 ca4 ca5 ca6 ca7 gnd iorq write select fb syscfg memcfg dmard opscfg f8io vcc equations: /memcfg = ca7*ca6*ca5*ca4*ca...

  • Page 137

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- pal 16l8 (u21) pin assignments: pa7 piorq pa6 p a 4 pa5 pa2 pa3 pao pal gnd pwrite ctcce sioce pioce fdcce softmr drvsel sndce pgsel vcc equations: if (vcc) /ctcce = pa7...

  • Page 138

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- pal 16r6 (u47) pin assignments: clock pd6 pd7 pdo pdl pd3 pd2 2drvin rst gnd gnd motor ddenp sidesel ds3 ds2 dsl dso internal vcc equations: /dso :=/pd0*pdl*pd2*pd3*rst ...

  • Page 139

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- r a s e n o : controls access to primary 64k trsdos operation- 0-32k base, not switchable 32-64k switchable address range 0-32: raseno = rfsh* lowp* a15* address range 3...

  • Page 140

    Service manual tandy 6000/6000-hd tan d y computer products ---------— -------------------------------------------------------- component layout, i/o processor pcb 8898423 - 141 -.

  • Page 141

    Service manual tandy 6000/6000-hd ------------------------------------------------------------------- tan d y computer products ----------------------------------------------------------------------- - 142 -.

  • Page 142

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, i/o processor pcb 8898423, solder side - 143 -.

  • Page 143

    Service manual tandy 6000/6000-hd ----------------------------------------------------------------------- tandy computer products ------------------------------------------------------------------------ parts lists, i/o processor pcb, 8898423(11/17/82) ref.No. Description part no. Cl capacitor, 0.1 ...

  • Page 144

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products -------— ---------------------------------------------------------- parts lists, i/o processor pcb, 8898423(11/17/82) ref.No. Description part no. C46 capacitor, 0.1 uf, ...

  • Page 145

    Service manual tandy 6000/6000-hd ----------------------------------------------------------------------- tandy computer products ------------------------------------------------------------------------ parts lists, i/o processor pcb, 8898423(11/17/82) - 146 - ref.No. Description part no. C91 capaci...

  • Page 146

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- parts lists, i/o processor pcb, 8898423(11/17/82) ref.No. Description part no. U15 ic, mc1489 quad ...

  • Page 147

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- parts lists, i/o processor pcb, 8898423(11/17/82) ref.No. Description part no. U62 ic, 74s112 flip...

  • Page 148

    Service manual tandy 6000/6000-hd ----------------------------------------------------------------------- tandy computer products ------------------------------------------------------------------------ parts lists, i/o processor pcb, 8898423(11/17/82) ref.No. Description part no. R17 resistor, lk o...

  • Page 149

    Parts lists, i/o processor pcb, 8898423(11/17/82) service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 150 - ref.No. Description part no. Resistor pak...

  • Page 150

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- parts lists, i/o processor pcb, 8898423(11/17/82) ref.No. Description part no. Staking pins e41 sta...

  • Page 151

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 152 -.

  • Page 152

    Service manual ta n d y computer products tandy 6000/6000-hd - 153 -.

  • Page 153

    Service manual tan d y computer products tandy 6000/6000-hd - 155 -.

  • Page 154

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 1 5 7 -.

  • Page 155

    Service manual tandy 6000/6000-hd — ----------------------------------------------------------------- t an d y computer products ----------------------------------------------------------------------- - 159 -.

  • Page 156

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 161 -.

  • Page 157

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- t an d y computer products ---------------------------------------------------------------------- - 163 -.

  • Page 158

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 7.5 video/keyboard interface board the video/keyboard interface board has two major functions. One is to control a built-in, high-resolution video monitor capable of dis...

  • Page 159

    Service manual tan d y computer products tandy 6000/6000-hd figure 7-10. Video/keyboard interface pcb block diagram - 166 -.

  • Page 160

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- the waveform at pin 8 of ul resembles a "raw" square wave with a frequency of approximately 12.48 mhz. At pin 2 of the same chip, the signal appears more like a "clean" ...

  • Page 161

    Service manual tan d y computer products tandy 6000/6000-hd figure 7-11. Timing diagram - 168 -.

  • Page 162

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- all these different signals are needed to allow the proper synchronization of the functions. The diagram represents accurately the propagation delay times provided by th...

  • Page 163

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- the best way to describe the mc6845 controller is to refer to the pin descriptions as noted in figure 7-12. The following paragraphs describe the function of each pin on...

  • Page 164

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- processor. It is active when either i/o port fc* or fd* is active (u31r pins 6 and 7). The register select line (rs) is an input that selects either the address regist...

  • Page 165

    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ the reset (res*) input is used to reset the crtc. It is an active low. When this signal is active, the crtc is forced into the following status: all the counters in crtc...

  • Page 166

    Service manual tandy 6000/6000-hd ta n d y computer products — -------------------------------------------------------------- figure 7-13. Character dot pattern - 173 -.

  • Page 167

    Service manual tandy 6000/6000-hd ta n d y computer products ---------------------------------------------------------------------- of the character generator. These also cycle binarily, but are incremented with each horizontal retrace time. The horizontal retrace time is the period in which the crt...

  • Page 168

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- ram/video ram select logic the block labeled ram/video ram select logic on the diagram in figure 7-13 is a decoder. That is, when the cpu is addressing its upper 2k by...

  • Page 169

    Service manual tandy 6000/6000-hd ta n d y computer products -------------------------------------------------------- o video board select logic this part of the system is called the port addressing block. It uses the lower eight lines of the address bus as shown by u27 (ls30) for the dual 2 to 4 li...

  • Page 170

    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ - 177 - bit 7 cd7 ) - if set (1), enables the 2k bytes ram, disables the upper 2k bytes of the bank's ram (f800h to ffffh) if reset (0), disables video ram, enables bank...

  • Page 171

    Service manual tandy 6000/6000-hd ta n d y computer products q the or gate is sometimes shown as above because we are using mostly active low signals. You can go from one gate to another by using demorgan's theorem. U - 178 - bit 6 1, video display disabled 0, video display enabled bit 5 (d5) - rtc ...

  • Page 172

    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ for the above example, the following equation applies: if we want to read the status of port ff, we activate the ffrd* signal to enable the 3-state buffers ls240, u38. T...

  • Page 173

    Service manual tandy 6000/6000-hd tandy computer products ---------------------------------------------------------------------- figure 7-14. Keyboard timing diagram actual 8 bit word at the output of the shift register (u 6) is buffered into the data bus (in other words, read by the cpu) . The rtc ...

  • Page 174

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- the cpu writes a word of data into the video ram. The crt controller, which automatically displays the information represented by video ram contents on the video screen,...

  • Page 175

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- is displayed "not in pieces" but as a single entity. After the eight dot scans are output, the electron beam is turned off and two rows (the 9th and 10th) of blank dots ...

  • Page 176

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- component layout, video/keyboard pcb 8898022 - 183 -.

  • Page 177

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- t an d y computer products ---------------------------------------------------------------------- circuit trace, video/keyboard pcb 8898022, component side - 184 -.

  • Page 178

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, video/keyboard pcb 8898022, solder side - 185 -.

  • Page 179

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- t an d y computer products ---------------------------------------------------------------------- parts lists, video/keyboard interface, 8898022 ref. No. Description part no. Capacitors cl capacit...

  • Page 180

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- parts lists, video/keyboard interface, 8898022 - 187 - ref no. Description part no. Resistors r2 re...

  • Page 181

    Service manual tandy 6000/6000-hd ----------------------------------------------------------------------- tandy computer products ------------------------------------------------------------------------ parts lists, video/keyboard interface, 8898022 ref no. Description part no. U25 ic, sn74ls157nds ...

  • Page 182

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- t a n d y computer products ---------------------------------------------------------------------- - 189 -.

  • Page 183

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 191 -.

  • Page 184

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tandy computer products ---------------------------------------------------------------------- 7.6 power supply board 7.6.1 functional specifications the power supply assembly for the tandy 6000/6...

  • Page 185

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- output voltages min typ max v01 4.95 5.00 5.25 v vo 2 11.40 12 .00 12 .60 v vo 3 see notes v04 21.60 24.00 26.40 v v05 -11.40 -12 .00 -12 .60 v v04, no load tolerance no...

  • Page 186

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- line conducted emi must meet fcc part 155 requirement for a class a computing device with a lodb margin. - 195 - min typ max hold up time: full load lo line 10 18 — — ...

  • Page 187

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- 7.6.2. Equipment for test set-up 1. Isolation transformer (minimum of 500 va rating) caution dangerously high voltages are present in this power supply. For the safety...

  • Page 188

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- output min load amps r for min load max load amps r for max load j2 pins +5v v01 i u) i • 1 o 1 1 1.66 ohm 13.36 .3 4 ohm 8,9, 30 w 130 w 11,12 +12 v02 .25 48 ohm .75 16...

  • Page 189

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 2. Visual inspection check power supply for any broken, burned, or obviously damaged components. Visually check the fuse. If any questions, check with an ohmmeter. 3. St...

  • Page 190

    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ 4. Check for b+ set up power supply and attach the x10 scope probe ground to the cathode side of d 5 . Slowly turn up the power and check for b+ on the cathode side of d...

  • Page 191

    Service manual tandy 6000/6000-hd tandy computer products-------------------------------------------------------------—------ 7.6.5 performance test each of these test conditions should be set up and noted to be within the limits specified in table 7-9. Test input +5 load +12 load +24 load -12 load ...

  • Page 192

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- component layout, power supply 8790047 - 201 -.

  • Page 193

    Service manual tandy 6000/6000-hd -------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- parts list, power supply 8790047 (astec components aa11082) ref no. Description mfr. Part no. Capaci...

  • Page 194

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- parts list, power supply 8790047 (astec components aa11082) ref no. Description mfr. Part no. Coil...

  • Page 195

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- parts list, power supply 8790047 (astec components aa11082) ref no. Description mfr. Part no. Jumpe...

  • Page 196

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products — — ----------------------------------------------- -------------- parts list, power supply 8790047 (astec components aa11082) ref no. Description mfr. Part no. Resistors...

  • Page 197

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- t an d y computer products ---------------------------------------------------------------------- - 206 -.

  • Page 198

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- - 207 -.

  • Page 199

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 7.7 sound board the sound pcb is a small board located in the front left corner of the base assembly; it is accessible when the cover/bezel assembly is removed from the ...

  • Page 200

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- parts list, sound pcb, 8898429 - 2 1 0 - ref no. Description part no. Cl capacitor, .022 mf, 50v, +...

  • Page 201

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- schematic 8000165, sound board 8898429 - 211 -.

  • Page 202

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 7.8 crt assembly the crt assembly on the tandy 6000/6000hd is supplied from several different manufacturers. The assembly consists of the crt, the crt monitor pcb, which...

  • Page 203

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 7.9 keyboard assembly the keyboard of the tandy 6000/6000 hd is an 82-key, low profile capacitive keyboard that utilizes an 8021 microprocessor chip. The microprocessor ...

  • Page 204

    Service manual tandy computer products tandy 6000/6000-hd parts list, low profile keyboard 8790522 - 214 - ref no. Description mfr. Part no. Capacitors cl capacitor, c .033 uf, 25v 32-00333-004 c2 capacitor, t 10 uf, 10v 32-00106-010 c3 capacitor, c .033 uf, 25v 32-00333-004 c4 capacitor, t 22 uf, 1...

  • Page 205

    Service manual tan d y computer products tandy 6000/6000-hd parts list, low profile keyboard 8790522 - 215 - xtal, 3.58 mhz, dip (yl) 48-00300-110 mounting plate 49-01143-000 switch, 30mm capacitor assy 61-04024-001 switch, 30mm capacitor assy lt 61-04024-002 switch, capacitor 30mm 61-04031-001 swit...

  • Page 206

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- - 2 1 6 -.

  • Page 207

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- - 217 -.

  • Page 208

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- 7.10 hard disk controller 7.10.1 system overview the tandy 6000 with built in hard disk is identical to the standard 6000, except for the additional 15-meg hd drive, i...

  • Page 209

    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ jumper location port range decoded el to e2 co to cf hex el to e3 70 to 7f hex el to e4 60 to 7f hex el to e5 50 to 5f hex table 7-11. Port decoding further decoding is ...

  • Page 210

    Service manual tandy 6000/6000-hd t an d y computer products ---------------------------------------------------------------------- 3. Drive control and interface the main device on the controller board is the western digital wd1010 (u26). This is a mos/lsi part that performs the function of drive c...

  • Page 211

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- data and control signals appear at connectors j3 and j2. By utilizing separate control output signa...

  • Page 212

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- increase in the voltage reference to vco (tp 3), causing the vco to speed up. Whenever the vco is running too fast,the error amp receives pump-down pulses and provides t...

  • Page 213

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 3. Adjust r2 until the drun signal just begins to toggle. Drun may be found on u27-15 for rev a boards or on test point 7 for all other board revisions. This is only a p...

  • Page 214

    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ - 225 - 1. Co — write protect register this port is for read only use and only bits d7 and d6 should be looked at. A logic one in location d7 indicates the primary drive...

  • Page 215

    Service manual tandy 6000/6000-hd tandy computer products 226 d4 id not found-set to one if desired cylinder,head,sector, or size cannot be found after 8 disk revolutions or if a crc error was encountered in the desired id field d5 not used-forced to zero d6 when set to one indicates a crc error was...

  • Page 216

    Service manual tandy 6000/6000-hd tandy computer products ------------------------------------------------------------------------ - 227 - 9. Cd — sdh register this is loaded with the desired sector size, drive number, and head number parameters using the following form. Bits sector bits head 6 5 si...

  • Page 217

    Service manual tandy 6000/6000-hd tan d y computer products d6 this bit reflects the state of the ready line from the drive. Upon an interrupt for an error this bit is frozen until the status register is read. D7 this bit is set whenever the wd1010 is busy accessing the drive or the sector buffer. 7...

  • Page 218

    Service manual tandy 6000/6000-hd t a n d y computer products --------------------------------------------------------------------- component layout, hard disk controller 8898798 rev. A - 229 -.

  • Page 219

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, hard disk controller 8898798 rev. A, component side - 230 -.

  • Page 220

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- circuit trace, hard disk controller 8898798 rev. A, solder side - 231 -.

  • Page 221

    Service manual tandy 6000/6000-hd ----------------------------------------------------------------------- tandy computer products ------------------------------------------------------------------------ parts list, hard disk controller pcb, 8898798 rev. A ref no. Description part no. Capacitors cl c...

  • Page 222

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tandy computer products ------------------------------------------------------------------------ parts list, hard disk controller pcb, 8898798 rev. A ref no. Description part no. Diodes crl diode...

  • Page 223

    Service manual tandy computer products tandy 6000/6000-hd parts list, hard disk controller pcb, 8898798 rev. A - 234 - ref no. Description part no. Integrated circuits u3* ic, 74f74, dual flip-flop, 14-pin 8015074 u4 ic, mc3487, line driver, 16-pin 8050487 u5 ic, mc3486, line receiver, 16-pin 805048...

  • Page 224

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- parts list, hard disk controller pcb, 8898798 rev. A ref no. Description part no. Staking pins tpl ...

  • Page 225

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 236 -.

  • Page 226

    Service manual ta n d y computer products tandy 6000/6000-hd - 237 -.

  • Page 227

    Service manual tandy 6000/6000-hd -----------------------------------------------------— ------------ ta n d y computer products — _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - 239 -.

  • Page 228

    Service manual tandy computer products tandy 6000/6000-hd - 241 -.

  • Page 229

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- 8/ parts lists/exploded views contained in this section are the parts lists and exploded views for the various subassemblies of the tandy 6000/6000-hd. Some parts are no...

  • Page 230

    8.1 base assembly s/a 889cc11, tandy 6000/6000-hd computer service manual tandy 6000/6000-hd ----------------------------------------------------------------------- tandy computer products ------------------------------------------------------------------------ item quan description part no 1 1 plug...

  • Page 231

    Service manual tan d y computer products tandy 6000/6000-hd figure 8-1. Exploded view, base assembly - 245 -.

  • Page 232

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- 8.2 card cage, main chassis, and power supply item quan description part no 1 1 pa n e l , right ca...

  • Page 233

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- figure 8-2. Exploded view, card cage, main chassis and power supply - 247 -.

  • Page 234

    Service manual tandy computer products tandy 6000/6000-hd 8.3 floppy disk drive - 248 - item quan description part no. 1 1 mount, disk drive 8729261 2 2 disk drive assembly 8790123 3 1 bar, rear mounting 8729262 4 1 bar, front mounting 8729263 5 1 l e n s , led 8719294 6 1 bezel, drive 9719295.

  • Page 235

    Service manual tandy 6000/6000-hd tan d y computer products ---------------------------------------------------------------------- figure 8-3. Exploded view, floppy disk drive assembly - 249 -.

  • Page 236

    Service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- 8.4 hard disk drive assembly item quan description part no 1 1 cable assembly, 34-pin connector 870...

  • Page 237

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- figure 8-4. Exploded view, hard disk drive assembly - 251 -.

  • Page 238

    Service manual tandy 6000/6000-hd —------ ta n d y computer products ---------------------------------------------------------------------- 8.5 bezel assembly item quan description part no 1 1 stiffener, bezel 8729515 2 1 b e z e l , front 8729261 3 1 video pcb 8898018 4 1 video mount 8729517 '5 1 c...

  • Page 239

    Service manual t tandy 6000/6000-hd t an d y computer p r o d u c t s _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ figure 8-5. Exploded view, bezel assembly.

  • Page 240

    Service manual tandy 6000/6000-hd ------------------------------------------------------------------------ tandy computer products ----------------------------------------------------------------------- 8.6 reset/power on indicator module item quan description part no. - 254 - item quan description ...

  • Page 241

    Service manual tandy 6000/6000-hd tan d y computer products figure 8-6. Exploded view, reset/power on indicator module - 255 -.

  • Page 242

    Service manual tandy computer products tandy 6000/6000-hd 8.7 case top assembly - 256 - item quan description part no. 1 1 case, top 8719469 2 1 spring, bar 8729158 3 1 d o o r , rear 8719248 4 2 bracket, strain relief 8729194.

  • Page 243

    Service manual tandy 6000/6000-hd tan d y computer products --------------------------------------------------------------------- figure 8-7. Exploded view, case top assembly.

  • Page 244

    Service manual tandy 6000/6000-hd ------------------------------------------------------------ tan d y computer products ---------------------------------------------------------------------- 8.8 keyboard assembly item quan description part no. 1 1 nameplate, keyboard 8729261 2 1 c o v e r , keyboar...

  • Page 245

    Service manual tandy 6000/6000-hd tan d y computer products --------------------------------------------------------------------- figure 8-8. Exploded view, keyboard assembly.

  • Page 246

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 260 -.

  • Page 247

    Service manual tandy 6000/6000-hd tandy computer products ----------------------------------------------------------------------- - 261 - appendices appendix a video monitor assembly appendix b floppy disk assembly appendix c hard disk assembly.

  • Page 248

    Service manual tandy 6000/6000-hd ---------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- - 262 -.

  • Page 249

    Video monitor assembly 8790614 (tce) service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- ref. No. Description part no. Capacitors c101 capacitor, 4.7 u...

  • Page 250

    Video monitor assembly 8790614 (tce) service manual tandy 6000/6000-hd ---------------------------------------------------------------------- ta n d y computer products ---------------------------------------------------------------------- - 264 - ref. No. Description part no. C401 capacitor, 220 uf...

  • Page 251

    Video monitor assembly 8790614 (tce) service manual tandy 6000/6000-hd --------------------------------------------------------------------- tan d y computer products ---------------------------------------------------------------------- ref. No. Description, part no. R205 resistor, 6.8 ohms, 1/4w, ...

  • Page 252

    Service manual tandy 6000/6000-hd t a n d y computer products ---------------------------------------------------------------------- video monitor assembly 8790608 (tce) - 266 - ref. No. Description, part no. Variable resistors vr201 variable resistor, 100k ohms 176910730a vr202 variable resistor, 2...

  • Page 255: Oem

    Oem operating and service manual tm848-1e and tm848-2e thinline™ flexible disk drives 48 tracks per inch ta n d o n c o r p o r a t i o n 20320 prairie street chatsworth, california 91311 ® copyright 1983 tandon corporation.

  • Page 256

    N o t ic e t h is d o c u m e n t, a n d th e in f o r m a t io n c o n ta in e d h e re in , is c o p y r ig h t b y t a n d o n c o r p o ra tio n a n d m a y n o t b e d u p lic a te d o r re p ro d u c e d , i n w h o le o r i n p a r t, w it h o u t th e p r io r w r i t t e n a p p r o v a l o...

  • Page 257

    C o n t e n t s s e c t io n 1 g e n e r a l d e s c r ip t io n i n t r o d u c t i o n ................................. .............................................................................................. 1-1 1.1 scope o f th e d o c u m e n t ..............................................

  • Page 258

    Section number title page number s e c t io n 1 g e n e r a l d e s c r ip t io n 3.7 d is k e t t e s ....................................................................................................................................... 3-13 l o a d in g th e d i s k e t t e .........................

  • Page 259

    Section page number title number s e c t io n 6 t r o u b l e s h o o t in g g u id e a n d r e p l a c e m e n t p r o c e d u r e s i n t r o d u c t i o n ................................................................................................................................ 6-1 6.1 s y m...

  • Page 260

    Illustrations f ig u r e s figure page n um ber t itle num ber 1-1 d is k d r iv e .................................................................................................... .............................. 1-4 2-1 d is k d r iv e o u t lin e d r a w in g .......................................

  • Page 261

    Tables 2-1 e le c t r ic a l a n d o p e r a tio n a l s p e c if ic a t io n s ....................................................................... 2-3 2-2 r e lia b ilit y s p e c if ic a t io n s .....................................................................................................

  • Page 263: Section  1

    Section 1 general description introduction 1.2 purpose of the drive t h is d o c u m e n t p ro v id e s r e q u ir e d in f o r m a t io n i n o r d e r to e v a lu a te o r in c o r p o r a te t a n d o n ’s d is k d r iv e in t o a s y s te m . T a n d o n c o r p o r a t i o n ’ s m o d e l n u ...

  • Page 264

    Daisy chain capability diskette lever lock solenoid (optional) t h e d r iv e p ro v id e s t h e a d d re s s s e le c tio n a n d g a t in g f u n c tio n s n e c e s s a ry to d a is y c h a in a m a x im u m o f f o u r u n it s a t th e u s e r’s o p tio n . T h e la s t d r iv e o n th e d a i...

  • Page 265

    D a ta re c o v e ry e le c tro n ic s in c lu d e a lo w - le v e l r e a d a m p lif ie r , f i l t e r , d if f e r e n t ia t o r , z e ro cro s s o v e r d e te c to r, a n d d ig it iz in g c ir c u its . N o ' d a ta -c lo c k s e p a ra tio n is p ro v id e d . I n a d d itio n , th e d r iv...

  • Page 266

    Figure 1-1 disk drive.

  • Page 267: Section  2

    Section 2 product specifications introduction t h is s e c tio n c o n ta in s th e m e c h a n ic a l, e le c tr ic a l, r e li a b i l i t y , a n d e n v ir o n m e n ta l s p e c ific a tio n s f o r th e t m 8 4 8 -1 e a n d t m 8 4 8 -2 e d riv e s . 2.1 mechanical specifications f ig u r e 2-...

  • Page 268

    2-2.

  • Page 269: Landon

    Table 2-1 electrical and operational specifications m e d ia 2 0 3 .2 0 m illim e t e r , 8 -in c h , i b m in d u s t r y - s ta n d a r d d is k e tte m e d ia l if e ( fo r re fe re n c e o n ly ) 3 x 106 passes p e r t r a c k t ra c k s p e r in c h 4 8 t p i, b o th d riv e s t ra c k s p e r ...

  • Page 270

    T a b l e 2 -1 (c o n t in u e d ) e l e c t r ic a l a n d o p e r a t io n a l s p e c if ic a t io n s f lu x r e v e rs a ls p e r in c h (f r p i) , in s id e t r a c k b o th d riv e s , s id e 0 6 ,5 3 6 f r p i t m 8 4 8 -2 e , s id e 1 6 ,8 1 6 f r p i u n f o r m a t t e d r e c o rd in g ...

  • Page 271: L A N D O N

    Figure 2 -3 + 2 4 volt d.C. Current, configuration 2 l a n d o n c o rp o ra tio n, c h a t s w o r t h , ca lif o r nia 9 1 3 1 1 179056-001 rev. A 2-5.

  • Page 272

    Table 2 -2 reliability specifications e r r o r r a te s , m a x im u m , e x c lu s iv e o f e x t e r n a l sources, e.G.: e le c tro n ic s , d e fe c tiv e a n d c o n ta m in a te d d is k e tte s s o ft e r r o r s (r e c o v e ra b le ) o ne i n 109 b it s h a r d e r r o r s (n o n re c o v ...

  • Page 273: Section  3

    Section 3 operation introduction t h is s e c tio n c o n ta in s in f o r m a t io n o n h o w to u n p a c k , c h e c k o u t, in s t a ll, a n d o p e ra te th e t m 8 4 8 -1 e a n d t m 8 4 8 -2 e d riv e s . 3.1 unpacking the drive t h e d r iv e s a re p a c k a g e d i n p r o te c tiv e c o...

  • Page 274

    Dust cover t h e d e s ig n o f a n e n c lo s u re s h o u ld in c o r p o r a te a m e a n s to p r e v e n t c o n ta m in a tio n fr o m loose ite m s , e.G., d u s t, l i n t , a n d p a p e r c h a d s in c e th e d r iv e does n o t h a v e a d u s t co ve r. Cooling h e a t d is s ip a tio n...

  • Page 275

    Table 3-1 drive interface lines and pin assignments ground pin signal 1 2 w r it e c u r r e n t s w itc h 3 4 m o to r o n c o n tr o l 1 5 6 m o to r o n c o n tr o l 2 7 8 t r u e r e a d y ( m o to r o n c o n tr o l 3, o p tio n a l) 9 10 t w o s id e d (s tra p p a b le ) (t m 8 4 8 -2 e o n l...

  • Page 276

    N o t e t m 8 4 8 - i e a n d t m 8 4 8 - 2 e d r iv e s in c lu d e a m ic ro p ro c e s s o r- c o n t r o l l e d b u f f e r e d s e e k c a p a b ilit y . T h e c o n tr o lle r m a y is s u e s te p p u ls e s o f one m ic ro s e ­ c o n d m in im u m w id t h , a n d f i f ­ te e n m ic ro s ...

  • Page 277

    Se le cts th e r e a d /w r ite h e a d o n s id e zero, th e lo w e r h e a d o f th e d riv e . A t r u e (lo w ) le v e l o n t h is lin e s e le c ts th e r e a d /w r ite h e a d o n sid e one, th e u p p e r h e a d o f th e d r iv e . W h e n s w it c h ­ in g fr o m o ne h e a d to th e o th...

  • Page 278

    Disk change t h is s tra p p a b le f e a tu r e p ro v id e s a t r u e (lo w ) s ig n a l to th e in t e r f a c e w h e n d r iv e s e le c t is a c ­ t iv a t e d i f th e d r iv e h a s g o n e fr o m a r e a d y to a n o t r e a d y c o n d itio n w h ile d e se le cte d . T h is lin e is re s...

  • Page 279

    Figure 3 -2 control and data tim ing requirements 3-7.

  • Page 280

    3.6 drive address and option strapping t h e d r iv e a d d re s s a n d o p tio n s tr a p p in g is d e te r m in e d b y th e d if f e r e n t ju m p e r c o n f ig u r a ­ tio n s r e q u ir e d f o r s p e c ific s y s te m a p p lic a ­ tio n s . I f ju m p e r c o n fig u r a tio n s a re c h...

  • Page 281

    Table 3 -3 option patching o ption trace d esignator as shipped installed n o t installed d r iv e s e le c t d s 1 - d s 4 d s l d s 2 - d s 4 h e a d s e le c t s i — s3 s2 s i, s3 h e a d s e le c t u s in g d r iv e s e le c t 1 b - 4 b x p o w e r s ave p s x s te p p e r p o w e r f ro m h e a...

  • Page 282

    Stepper motor power (ps, ps*, ds, hl) w h e n th e p s ju m p e r is in s ta lle d , s te p p e r m o to r p o w e r is c o n tr o lle d b y th e d r iv e s e le c t lin e , d s , o r th e h e a d l o a d lin e , h l . W h e n e it h e r lin e is t r u e (lo w ), th e s te p p e r m o to r is d r iv...

  • Page 283

    Figure 3-3 lsi circuit board assembly 3-11.

  • Page 284

    Ready and true ready (r and tr) disk change (dc) w h e n th e r ju m p e r is in s ta lle d , th e r e a d y s ig n a l is a v a ila b le a t th e in te r fa c e . W h e n th e t r ju m p e r is in s ta lle d , th e t r u e r e a d y s ig n a l is a v a ila b le a t th e in te r fa c e . T h e r ju ...

  • Page 285

    Write current switch (xc and ic) t h e x c o p tio n a llo w s th e h o s t c o n t r o lle r to s w itc h th e w r it e c u r r e n t in d e p e n d e n tly o f th e d r iv e ’s o n b o a rd m ic ro p ro c e s s o r. I t is fa c to r y in s ta lle d . T o im p le m e n t th e ic o p tio n , re m o ...

  • Page 286

    Ta ble 3 - 4 diagnostic mode of operation 3-14 d l m 4 m 3 m l t e st d e s c rip tio n o f t e st — — — — 0 s eek to t ra c k 0, a n d tu r n on s p in d le m o to r . T h is te s t seeks th e c a r r ia g e to t r a c k 0, a n d t u r n s o n th e s p in d le m o to r. I t m a y be u se d to c h e...

  • Page 287

    Table 3 -4 (continued) diagnostic mode of operation d l m 4 m 3 m l t e s t d e s c rip tio n o f t e s t x x 1 0 /a m o n it o r th e w r ite p ro te c t sensor. T h is te s t c h e c k s th e w r it e p r o te c t sensor. T h e f r o n t p a n e l l .E .D . S h o u ld t u r n o n a n d o f f b y m...

  • Page 288

    W h e n t h e s lo t is c o v e re d w i t h a n o p t ic a lly op a q u e , s e lf-a d h e s iv e ta b , th e d is k e tte is w r it e e n a b le d . W h e n th e ta b is re m o v e d , th e d is k e tte is w r it e p ro te c te d . Diskette handling and storage i t is im p o r t a n t th e d is k ...

  • Page 289

    Figure 3-5 diskette care and handling 3-17.

  • Page 291: Section  4

    Section 4 theory of operation introduction t h is s e c tio n c o n ta in s a d e s c r ip tio n o n th e th e o r y o f o p e ra tio n o f th e d r iv e . T h e d is c u s s io n b e g in s w i t h a g e n e ra l s u m m a r y o f m a g n e tic d a ta re c o rd in g , fo llo w e d b y a d e s c r i...

  • Page 292

    Figure 4-2 fm recording magnetization profiles a s th e d is k s p in s , th e m a g n e tic fie ld s o f th e s to re d d a ta pass s u c c e s s iv e ly u n d e r t h e h e a d . T h e c h a n g in g fie ld s in d u c e , i n th e h e a d , a n a . C. V o lta g e s ig n a l w h ic h is th e n a m ...

  • Page 293

    4.2 components of the drive t h e d r iv e c o n ta in s th e e le c tr ic a l a n d m e c h a n i­ c a l c o m p o n e n ts r e q u ir e d to p e r fo r m f o u r m a jo r f u n c tio n s : 1. G e n e ra te a n d in t e r p r e t c o n tr o l a n d s ta tu s s ig n a ls . 2. P o s itio n th e r e a...

  • Page 294

    Figure 4-4 interconnect block diagram 4-4.

  • Page 295

    Figure 4 -6 track o timing 4-5.

  • Page 296

    A lo w , a c tiv e s ig n a l is s u p p lie d to th e l s i c h ip , w h ic h s u p p lie s a n a c tiv e s ig n a l to th e m ic r o ­ p ro ce sso r a n d e n a b le s th e i n p u t a n d o u t p u t s ig n a ls in t e r n a lly . Lever lock solenoid w h e n th e le v e r lo c k s o le n o id o p...

  • Page 297

    Figure 4-7 stepper motor current 4.5 read/write data t h e c o m p o n e n ts o f th e d r iv e r e q u ir e d to re a d a n d w r it e d a ta a re : 1. R e a d /w r ite h e a d a s s e m b ly 2. S id e s e le c t c ir c u it s 3. W r ite /e r a s e c ir c u it s 4. R e a d d a ta c ir c u it s 14. ...

  • Page 298

    T h e w in d in g o n th e h e a d is c e n te r ta p p e d . D u r in g a w r i t e o p e ra tio n , c u r r e n t fr o m th e w r it e c u r r e n t so u rc e fo llo w s i n a lte r n a te h a lv e s o f th e w in d in g , u n d e r c o n tr o l o f th e w r it e w a v e fo r m g e n r a to r . W ...

  • Page 299

    Read data circuits t h e re a d e le c tro n ic s c o n s is t o f: 1. R e a d o n ly a n d s id e s e le c t c ir c u it 2. R e a d a m p l i f i e r a n d l in e a r p h a se f i l t e r 3. D if f e r e n t ia t o r 4. C o m p a ra to r, t im e d o m a in f ilt e r , a n d d ig it iz e r t h e r e...

  • Page 300

    4.6 spindle control t h e c o m p o n e n ts o f th e d r iv e r e q u ir e d to c o n ­ t r o l th e s p in d le a r e : 1. S p in d le m o to r e n a b le c ir c u it 2. S p in d le m o to r c o n tr o l c ir c u it spindle motor enable circuit t h e m o to r o n s ig n a l is d e riv e d fr o m t...

  • Page 301: Section  5

    Section 5 maintenance checks and adjustments introduction t h is s e c tio n is f o r th e use o f th e o e m r e p a ir a n d s e rv ic e d e p a rtm e n ts . I t c o n ta in s th e m a in te n a n c e c h e c k s a n d a d ju s tm e n ts used d u r in g th e n o r m a l l i f e o f th e d r iv e ....

  • Page 302

    Figure 5-1 logic circuit board with test points 7. A s s o c ia te d p o w e r a n d in te r fa c e ca b le s. 8. A n u m b e r 1 p h illip s s c re w d riv e r. 9* a n u m b e r 2 p h illip s s c re w d riv e r. 10. A s e t o f a lle n w re n c h e s . 11- a f l a t b la d e s c re w d riv e r. 12....

  • Page 303

    4. V e r i f y th e p o w e r s u p p ly v o lta g e s a re w i t h i n to le ra n c e s . 5. E n s u re a d r iv e s e le c t ju m p e r is in p la c e . 6. S e le c t th e d r iv e . 7. V e r i f y th e f r o n t p a n e l l .E .D . Is i l l u ­ m in a te d 8. D e s e le c t th e d riv e . 9. E n ...

  • Page 304

    Figure 5-2 timing disk figure 5-3 hub center line and track location 5-4.

  • Page 305

    N o t e t h e t r a c k 38 r a d iu s is 2 .8 2 0 7 ± .0 0 2 0 in c h e s fr o m th e c e n te r o f th e h u b . O th e r t r a c k lo c a tio n s a re c o m p u te d based u p o n 48 t p i. 4. S e le c t th e d riv e . 5. In s e r t a r a d ia l t r a c k a lig n m e n t d is k ­ e tte , d y s a n...

  • Page 306

    10. S te p th e d r iv e to t r a c k 0, th e n s te p i t b a c k to t r a c k 38. 11. V e r i f y th e c a ts e y e p a tte r n . 12. S te p th e d r iv e to t r a c k 42 o r h ig h e r ; th e n , s te p i t b a c k to t r a c k 38. 13. V e r if y th e c a ts e y e p a tte r n . 14. S w itc h to h...

  • Page 307

    5.7 index checks and adjustment t h e in d e x a d ju s t m e n t c h a n g e s th e t im e p e rio d fr o m th e in d e x p u ls e to th e s t a r t o f th e d a ta i n h a r d s e c to re d d is k e tte s . T h e a d ju s t ­ m e n t s h o u ld b e c h e c k e d a f t e r th e d r iv e h a s b e e...

  • Page 308

    N o t e h e a d 1 s h o u ld m e e t th e sam e to le ra n c e . 11. I f e it h e r h e a d 0 o r h e a d 1 does n o t m e e t th e to le ra n c e , a d ju s t th e in d e x sensor. 12. W h e n b o th in d e x m e a s u re m e n ts o n a d o u b le -s id e d d r iv e o r th e o ne in d e x m e a s u...

  • Page 309

    1. S e t u p th e o sc illo s c o p e to re a d : c h a n n e l a : u 2 , p in 14 c h a n n e l b : u 2 , p in 15 g ro u n d : t e s t p o in t 8 r e a d d i f f e r e n t i a l l y : a p lu s b , b in v e r te d t im e b a s e : 0.5 m illis e c o n d p e r d iv is io n e x t e r n a l t r ig g e r ...

  • Page 310

    Track 0 sensor check 1. S et u p th e o scillo sco p e t o re a d : c h a n n e l a : u 2 , p in 14 c h a n n e l b : u 2 , p in 15 g ro u n d : t e s t p o in t 8 r ead d i f f e r e n t ia lly : a p lu s b , b in v e r te d t im e b a se : 2 0 m illis e c o n d s p e r d iv is io n e x t e r n a l...

  • Page 311

    Figure 5-11 track 0 retaining screw h e a d a m p lit u d e ca n be v e r if ie d b y e s ta b lis h ­ in g a n o m in a l v a lu e o f a m p litu d e f o r th e d is k ­ e tte o n a k n o w n w o r k in g d r iv e . I n a l l cases, a m p litu d e s a b o v e 2 00 m i l l i v o l t s p e a k to p e...

  • Page 312

    5.11 cone centering check c one c e n te r in g is th e a b i l i t y o f th e cone c la m p ­ in g m e c h a n is m to c e n te r th e d is k e tte o n th e h u b c a u s in g i t t o r o t a t e c o n c e n tr ic a lly . T h is c h e c k s h o u ld be m a d e w h e n e v e r th e cone le v e r a s...

  • Page 313: Section  6

    Section 6 troubleshooting guide and replacement procedures introduction t h is s e c tio n is d e s ig n e d to h e lp lo c a te a n d c o r­ r e c t fa ilu r e s r e la te d to th e d r iv e . T a b le 6-1 is a tr o u b le s h o o tin g g u id e o u t lin in g th e p ro b le m , it s p o s s ib le ...

  • Page 314

    T a b l e 6 -1 t r o u b l e s h o o t in g g u id e c ond itio n possible cause recommended a ctio n n o in d e x . D is k e tte n o t in s e rte d . In s e r t d is k e tte . L e v e r n o t closed. C lose le v e r. U n i t n o t s e le c te d . V e r i f y u n i t s e le c t a n d ju m p e r c o ...

  • Page 315

    T a b l e 6 -1 t r o u b l e s h o o t in g g u id e (continued) c ondition possible cause recommended a ction w i l l n o t w r it e . D is k e tte is w r it e p ro te c te d . I n s t a ll w r it e ta b on d is k e tte . In te r fa c e n o t e n a b le d . V e r if y w r it e e n a b le , s e le c...

  • Page 316

    T a b l e 6 -1 t r o u b l e s h o o t in g g u id e (continued) c ondition possible cause recommended a ctio n f a ils d r iv e s e le c t c h e c k . P o w e r n o t a p p lie d to th e d riv e . V e r if y p o w e r s u p p ly v o lta g e s . D r iv e n o t s e le cte d . V e r i f y p ro p e r j...

  • Page 317

    T a b l e 6 -1 t r o u b l e s h o o t in g g u id e (continued) c ondition possible cause recommended a ction f a ils in d e x c h e c k s a n d a d ju s tm e n t. D is k e tte n o t c e n te rin g . A lig n m e n t d is k e tte d e fe c tiv e . See: n o in d e x . See: f a ils c e n te r in g ch e...

  • Page 318

    Table 6 -2 checks and adjustment guide r e c o m m e n d e d checks a n d a d ju stm en ts parts or assem blies replaced p o w e r /d r iv e s e l e c t c h e c k w r it e p r o t e c t s e n s o r d r iv e m o t o r s p e e d radial t r a c k a l ig n m e n t in d e x a z im u t h t r a c k 0 s e n...

  • Page 319

    Logic circuit board replacement removal 1. R e m o v e a l l c o n n e c to rs fr o m th e c ir c u it b o a rd ( f ig u r e 6 -1 ). N o te t h e ir lo c a tio n . 2. R e m o v e th e tw o c ir c u it b o a rd m o u n t in g screw s. 3. S lid e th e c ir c u i t b o a rd to w a r d th e b a c k o f ...

  • Page 320

    Cone assembly removal 1. R e m o v e th e s c re w t h a t a tta c h e s th e cone b r a c k e t to th e cone a lig n m e n t a r m ( f ig u r e 6 -2 ). 2. U n la t c h th e d is k e tte le v e r. 3. S w in g th e c one a s s e m b ly u p 9 0 d e ­ grees so t h a t i t p o in ts to w a r d th e sid ...

  • Page 321

    Installation 1. G e n tly in s e r t th e c one a s s e m b ly . 2. C a r e f u l l y in s e r t t h e e - r in g , f l a t w a s h e r, a n d w a v e w a s h e r t h a t h o ld s on th e cone s h a f t (see f ig u r e 6 -3 ). 3. S w in g th e c one a s s e m b ly d o w n 90 d e ­ g re e s so t h a ...

  • Page 322

    Diskette lever removal 1. P r y o f f th e c o v e r t h a t h id e s th e d is k e tte le v e r ’s r e t a in in g s c re w ( f ig u r e 6 -4 ). 2. R e m o v e th e d is k e tte le v e r ’s r e t a in in g screw . 3. C a r e f u lly re m o v e th e d is k e tte le v e r. Installation 1. P u t th e ...

  • Page 323

    Front panel installation removal 1. R e m o v e th e d is k e tte le v e r. 2. R e m o v e th e fo u r m o u n tin g screw s, tw o o n e a c h side, t h a t a t t a c h th e f r o n t p a n e l to th e ch a ssis (f ig u re 6 -5 ). 3. L i f t o f f th e f r o n t p a n e l, b e in g c a r e fu l t h ...

  • Page 324

    Bridge assembly removal 1. R e m o v e th e l o g ic c ir c u it b o a rd . 2. R e m o v e th e d is k e tte le v e r. N o t e e n s u re th e u p p e r h e a d l i f t a r m is o n to p o f th e lo a d a r m a s s e m b ly . 3. R e m o v e th e fo u r b r id g e m o u n t in g s c re w s a t t a c ...

  • Page 325

    Figure 6-7 bridge assembly d r iv e m o t o r 5. C u t th e t ie w ra p s a tt a c h in g th e d r iv e m o to r c o n n e c to r to th e c a b le h a rn e s s ( f ig u r e 6 -8 ). 6. R e m o v e th e m o u n tin g s c re w a t t a c h in g removal th e h e a t s in k to th e ch a ssis. T h e h e a ...

  • Page 326

    Figure 6-8 drive motor mounting screws installation 1. I n s t a ll th e n e w d r iv e m o to r a s s e m b ly , a lig n in g th e m o u n tin g h o le o n th e to p sid e o f th e chassis. 2. I n s t a ll a n d t ig h t e n th e th re e m o u n tin g screw s ( f ig u r e 6 -8 ). 3. I n s t a ll a ...

  • Page 327

    Figure 6-9 heat sink and cable slot load arm assembly removal 1. R e m o v e th e l o g ic c ir c u it b o a rd , 2. R e m o v e th e m o u n tin g s c re w a n d w a s h e r t h a t a re used to a tta c h th e l o a d a r m a s s e m b ly to th e b rid g e a s s e m b ly (f ig u re 6 -1 0 ). 3. C a...

  • Page 328

    Figure 6-10 load arm assembly track 0 sensor assembly removal 1. R e m o v e p l l fr o m th e l o g ic c ir c u it b o a rd . 2. C u t th e t ie w ra p s t h a t h o ld th e c a b le h a rn e s s , a n d re m o v e th e p l l w ire s ( f ig u r e 6 -1 1 ). 3. R e m o v e th e p l l w ir e s fr o m ...

  • Page 329

    Figure 6-11 track 0 sensor assembly write protect sensor assembly installation removal 1. R e m o v e p io fr o m th e c ir c u i t b o a rd . 2. R e m o v e t h e m o u n t i n g s c r e w s a t t a c h in g th e w r it e p r o te c t s ensor a s s e m b ly to th e c h a s s is (see f ig u r e 6 - ...

  • Page 330

    Figure 6-12 write protect sensor assembly installation 1. M o u n t th e m o to r s w itc h a s s e m b ly to t h e b r i d g e , u s i n g t h e o r i g i n a l m o u n t in g scre w s a n d n u t p la te . 2. R o u te th e m o to r s w itc h c a b le s u s in g th e c a b le h a rn e s s t ie w ra...

  • Page 331

    Figure 6-13 motor switch assembly index sensor assembly removal 1. R e m o v e th e l o g ic c ir c u it b o a rd . 2. R e m o v e th e d is k e tte le v e r. 3. R e m o v e th e f r o n t p a n e l. 4. R e m o v e th e b r id g e a s s e m b ly , a n d u p p e r in d e x sensors (f ig u re 6 -1 4 )...

  • Page 332

    Figure 6-14 index sensor assembly, top view installation 1. M o u n t th e lo w e r in d e x se n so r to th e chassis. 2. S lid e th e u p p e r in d e x se n so r c a b le a n d c o n n e c to r th r o u g h th e s lo t i n th e chassis. 3. I n s t a ll th e l e f t r a i l b y p re s s in g i t i...

  • Page 333

    Figure 6-15 index sensor assembly, bottom view diskette ejector assembly removal 1. R e m o ve th e l o g ic c ir c u it b o a rd . 2. R e m o v e th e d is k e tte le v e r. 3. R e m o v e th e b r id g e a s s e m b ly . 4. R e m o v e th e t r ig g e r a s s e m b ly (f ig u r e 6 -1 6 ). 5. R el...

  • Page 334

    Figure 6-16 diskette ejector assembly stepper band removal 1. R e m o v e th e c ir c u i t b o a rd . 2. L i f t o f f th e s te p p e r b a n d fr o m th e s p r in g te n s io n e r ( f ig u r e 6 -1 7 ). 3. L i f t o f f th e s te p p e r b a n d w h e re i t a t ­ ta c h e s to th e f r o n t o...

  • Page 335

    Figure 6-17 stepper band stepper motor assembly removal 1. R e m o v e th e l o g ic c ir c u i t b o a rd . 2. R e m o v e th e s te p p e r b a n d . 3. R e m o v e th e th r e e m o u n tin g scre w s a t ­ ta c h in g th e s te p p e r m o to r a s s e m b ly to th e c h a s s is ( f ig u r e 6 ...

  • Page 336

    Figure 6-18 stepper motor head carriage assembly removal 1. R e m o v e th e l o g ic c ir c u it b o a rd , 2. R e m o v e th e s te p p e r b a n d . 3. R e m o v e th e tw o c lip s t h a t h o ld th e c a r ­ ria g e g u id e r a ils to th e ch a s s is (f ig u r e 6 -1 9 ). 4. C a r e f u lly l...

  • Page 337

    Figure 6-19 head carriage 6-25.

  • Page 339: Appendix A

    Appendix a recommended spare parts and major assemblies this appendix contains the recommended spare parts and the m ajor assembly drawings for the drive. P a rt numbers on this list should be used for ordering spare parts. A spare parts list w ith prices for parts and services is available from tan...

  • Page 340

    A-2.

  • Page 341

    \ i ; t i a-3.

  • Page 343: Appendix  B

    Appendix b circuit board schematics and drawings t h is a p p e n d ix c o n ta in s th e c u r r e n t c ir c u it b o a rd s c h e m a tic s a n d c ir c u it b o a rd d ra w in g s fo r th e t m 8 4 8 -1 e a n d t m 8 4 8 -2 e . D ra w in g n u m b e r t itle p age n u m b e r 2 1 0 7 7 2 r e v i...

  • Page 349: Ta N D O N

    Ta n d o n corporate offices 20320 prairie street chatsworth, ca 91311 telephone no.: (213) 993-6644 telex no.: 194794 twx no.: 910-494-1721 printed in u.S.A. P/n 179056-001a (t5014a 11-83).

  • Page 351: Oem

    Oem operating and service manual tm501, tm502, tm503 disk drives 345 tracks per inch ta n d o n c o r p o r a t io n 20320 prairie street chatsworth, ca 9 1 3 1 1 © c o p y r ig h t 1983 t a n d o n c o r p o r a t io n.

  • Page 352

    N o t ic e t h is d o cu m e n t, a nd the in fo rm a tio n co n ta in e d herein, is c o p y rig h t b y t a n d o n c o rp o ra tio n a nd m a y n o t be d u p lic a te d o r re p ro d u ce d , in w hole o r in p a rt, w ith o u t th e p r io r w ritte n a p p ro v a l o f t a n d o n c o rp o ra ...

  • Page 353

    Contents section 1 general description introduction........................................................................................................... 1-1 1.1 scope of the document......................................................................................... 1-1 1.2 purpose of the...

  • Page 354

    Section number t it le page number s e c t i o n 4 t r o u b l e s h o o t i n g g u i d e a n d r e p l a c e m e n t p r o c e d u r e i n t r o d u c t i o n ............................................... ................................................................................. 4-1 4 .1 ...

  • Page 355

    Illustrations f ig u r e s f ig u r e p a g e n u m b e r t it le n u m b e r 1-1 d is k d r iv e ........................................................................................................................................... 1-2 2-1 d is k d r iv e o u tlin e d r a w in g .................

  • Page 357: Section  1

    Section 1 general description introduction t h is m an u a l p rovides u se fu l in fo rm a tio n to assist th e custom er w hen in c o rp o ra tin g th e t a n d o n rig id d isk d rive in to a system. T a n d o n c o rp o ra tio n ’ s t m 5 0 0 series o f drives are fu ll fe a tu re , 5 -1 /4 -in ...

  • Page 358

    Activity indicator the a c tiv ity in d ic a to r is located o n the fr o n t panel o f the d rive . I t is a u to m a tic a lly illu m in a te d w hen the d riv e is selected. Air filtration a self-co n ta in e d , re c irc u la tin g a ir filtr a tio n system supplies clean a ir th ro u g h a 0 .3...

  • Page 359: Section  2

    Section 2 product specifications introduction this section contains the mechanical, electrical and operational, reliability, and environmental specifications for the tm501, tm502, and tm503 disk drives. 2.1 mechanical specifications the mechanical and physical dimensions are contained in figure 2-1....

  • Page 360: Andon

    N o te : w e ig h t is 3.0 k ilo g ra m s , 6.5 pounds m a x im u m figure 2-1 disk drive outline drawing t andon corporation •chatsworth, california 91311 179045-001 rev. A 2-2.

  • Page 361: T A N D O N

    Table 21 electrical and operational specifications m e d ia l u b ric a te d , 130 m illim e te r, p lated a lu m in u m d isk t ra cks per in c h 345 t p i spacing, t ra c k to t ra c k 2.9 m ilinches n u m b e r o f c ylin d e rs 306 cylinders n u m b e r o f t ra cks tm 501 612 tra cks t m 5 0 2 ...

  • Page 362: Ta N D O N

    Table 2-1 (continued) electrical and operational specifications m a x im u m f lu x reversal d ensity 9090 f r p i u n fo rm a tte d c a p a c ity p er d riv e tm 501 6.38 megabytes t m 5 0 2 12.76 megabytes t m 5 0 3 19.14 megabytes u n fo rm a tte d c a p a c ity p er surface 3.19 megabytes u n fo...

  • Page 363: Andon

    Figure 2-2 typical starting currents t andon corporation •chatsworth, california 91311 179045-001 rev. A 2-5.

  • Page 364: Tandon

    Table 2*2 reliabl1lity specifications soft and hard read error rates, exclusive of media defects f o r d ata th a t has been v e rifie d p re vio u sly as e rro r free, and w hen used in c o n ju n c tio n w ith a data separator and phase lo c k lo o p o f good design, the recoverable (s o ft) read ...

  • Page 365: T A N D O N

    Table 2-3 environmental specifications a m b ie n t t e m p e ra tu re o p e ra tin g 4°c to 50°c, 39°f to 122°f n o n o p e ra tin g -40°c to 60°c, -40°f to 140°f t e m p e ra tu re g ra d ie n t o p e ra tin g 10°c per h o u r, 18°f per h o u r n o n o p e ra tin g b e lo w th a t causing condensa...

  • Page 367: Section  3

    Section 3 operation introduction t h is section con ta in s in fo rm a tio n p e rtin e n t to the h a n d lin g , in sp e ctio n , in s ta lla tio n , and o p e ra tio n o f the t m 5 0 0 series o f drives. 3.1 unpacking the drive sure to use p r io r steps in reverse o rd e r, and ensure the fo a ...

  • Page 369

    Dust cover t h e design o f an enclosure should in c o rp o ra te a means to p re ve n t c o n ta m in a tio n fro m loose item s, e.G., d u st, lin t, and paper chad since the d riv e does n o t have a dust cover. Free air flow w h e n th e d riv e is m o u n te d so the com ponen ts have access to...

  • Page 370

    Figure 3-2 j1 edge connector dimensions figure 3-4 j3 power connector 3-4 figure 3-3 j2 edge connector dimensions.

  • Page 371

    Table 3-1 drive interface signals and pin assignments in te rfa ce p in n u m b e r c o n n e cto r signal g ro u n d signal type i / o nam e o f signal p i 2 (1) s i spare 4 (3) s i head select 22 6 (5) s i w rite gate 8 (7) s o seek c om plete 10 (9) s o t ra c k 0 34-p in 12 (h) s o f a u lt r ib...

  • Page 372: Interface Line

    J3/p3 connector d . C . P o w e r co n n e cto r j3 is a fo u r-p in a m p m a te -n -l o k co n n e c to r, p / n 350211-1, m o u n te d o n th e solder side o f the c irc u it b o a rd . T h e re co m ­ m ended m a tin g c o n n e c to r, p 3, is a m p p / n 1-480424-0, u tiliz in g a m p pins p /...

  • Page 373

    Figure 3-5 radial configuration 3-7.

  • Page 374

    Figure 3-6 daisy chain control lines.

  • Page 375

    Figure 3-7 control signal/driver receiver circuit combination 3-9 write gate the active state o f this signal or logical zero level enables write d ata to be written on the disk. The inactive state o f this signal enables the data to be transferred from the drive. In addition, the inac­ tive state e...

  • Page 376

    Table 3-2 head select lines h ead select l in e h ead selected 22 2' 2° jum per 3 p w i3 o u t t m 5 0 1 , t m 5 0 2 jum per 3 pw 13 in t m 5 0 3 1 1 1 0 0 1 1 0 i 1 1 0 1 2 2 1 0 0 3 3 0 1 1 0 4 0 1 0 1 5 0 0 1 2 0 0 0 0 3 1 h ead recovery tim e (head-to-head select, w rite -to - read recovery, o r...

  • Page 377

    Figure 3-8 step mode timing buffered seek t he b u ffe re d seek uses an o n b o a rd m icroprocessor th a t calculates the m ost e ffic ie n t seek a lg o rith m fo r the user. T h e user need o n ly issue step pulses in accordance w ith the tim in g show n (see f igure 3-9). Step pulses are issued...

  • Page 378

    Direction in seek complete t his signal defines the d ire c tio n o f m o tio n o f the re a d /w rite head w hen the step line is pulsed. A n open c irc u it o r lo g ic a l false defines the d ire c tio n as “ o u t” . I f a pulse is applied to the step lin e , the re a d /w rite heads m ove aw ay...

  • Page 379

    Ready w hen tru e , the ready signal, together w ith seek : c om plete, indicates th a t the d rive is ready to read, w rite o r seek, and the i / o signals are v a lid . W h e n th is lin e is false, a ll c o n tro lle r-in itia te d fu n c tio n s are in h ib ite d . The ty p ic a l tim e a fte r ...

  • Page 380: Drive Address And

    Mfm write data t he o p tio n p ro g ra m m in g guide is co n ta in e d in t able 3-3. T h is is a d iffe re n tia l p a ir o f lines th a t d e fin e the flu x tra n s itio n to be w ritte n o n th e tra c k . T he tra n ­ s itio n o f th e + m f m w rite d a ta lin e g o in g m ore p o sitive th ...

  • Page 381

    Table 3-3 option programming guide w 1-w3 jumper function factory programmed usage w l t ra c k f ault o in s ta ll f o r excess tra c k fa u lt. W 2 test 0 in s ta ll f o r fa c to ry test. W 3 disable l im it o in s ta ll to disable s o ft lim its . W 4 spin select o in s ta ll fo r spin select. W...

  • Page 382

    Figure 3-11 recommended shipping pack design, configuration 1.

  • Page 383

    Figure 3-11 (continued) recommended shipping pack design, configuration 1 3-17.

  • Page 384

    Figure 3-12 recommended shipping pack design, configuration 2 3-18.

  • Page 385

    Figure 3-13 recommended shipping pack design, configuration 3 3-19.

  • Page 386

    Figure 3-13 (continued) recommended shipping pack design, configuration 3 3-20

  • Page 387

    Figure 3-14 load graph 3-21.

  • Page 389: Section  4

    Section 4 troubleshooting guide and replacement procedure introduction t h is section is designed to help locate and co rre ct fa ilu re s related to the d rive . T able 4-2 is a tro u b le s h o o tin g guide o u tlin in g the p ro b le m , its possible cause, a nd the recom m ended a c tio n . T h...

  • Page 390

    Figure 4-1 test point locations.

  • Page 391

    Table 4-2 troubleshooting guide p ro b le m possible cause r ecom m ended a c tio n n o a c tiv ity la m p . N o t selected. L a m p n o t plugge d in . L a m p fa u lty . L o g ic b o a rd fa u lty . C heck f o r co rre c t drive select ju m p e r. C heck c o n n e c to r p-7. Replace la m p . Repl...

  • Page 392

    Table 4-2 (continued) troubleshooting guide p ro b le m possible cause recom m ended a c tio n d riv e does n o t seek o r restore. D riv e n o t selected. C heck d riv e select ju m p e r. Stepper m o to r n o t plugged in . C heck c on n e cto r p-8. L o g ic b o a rd fa u lty . Replace lo g ic b ...

  • Page 393

    Table 4-2 (continued) troubleshooting guide p ro b le m possible cause recom m ended a c tio n does n o t read. Im p ro p e r p o s itio n . See “ d riv e does n o t seek o r re s to re .” d riv e n o t ready. See “ d riv e n o t re a d y .” does n o t w rite . N o w rite gate fo r w ritin g . C hec...

  • Page 394

    O figure 4-3 read data waveforms 15 tpr + and 14 tpr o 4-6.

  • Page 395

    4.2 r e p l a c e m e n t p r o c e d u r e s replacement d o n o t ro ta te spindle m o to r o r head p o s itio n in g m echanism . Dam age to heads a n d /o r m e d ia m ay occur. R em ove p o w e r p r io r to replacing parts. The fo llo w in g assemblies m ay be replaced: c o n tro l and d a ta...

  • Page 396

    T o replace the assem bly, reverse steps 1 th ro u g h 4. Adjustment t o a d ju s t th e l in e a r b rake a ssem bly: 1. Loosen the 5 /1 6 -in c h m o u n tin g n u t. 2. Set th e feeler gauge, adjusted to 0.014 in ­ ches, between th e b ra ke pad and th e sp in ­ dle d riv e m o to r r o to r. 3. ...

  • Page 397

    Figure 4-4 index sensor 4-9.

  • Page 398

    Front panel replacement removal t o rem ove th e fr o n t panel: 1. W edge a ta p e r sh im 0.030 in c h u n d e r the edge o f th e fr o n t panel. 2. R em ove th e fr o n t panel fro m th e d riv e fra m e . 3. Clean the fr o n t p a n e l th o ro u g h ly w ith solvent. Replacement t o replace th...

  • Page 399

    Figure 4-5 voltage spikes frame assembly removal t o rem ove the fram e a ssem bly: 1. R em ove th e c o n tro l and d a ta c irc u it b o a rd . 2. R em ove th e s pindle c o n tro l c irc u it b o a rd . 3. R em ove the three fra m e nuts and the six washers. 4. R em ove th e fram e a ssem bly. Re...

  • Page 400

    Figure 4-6 track 0 adjustment 4-12.

  • Page 401: Appendix A

    Appendix a recommended spare parts list and major assemblies a l l assemblies w ith p a rt num bers are a vailable f o r purchase as spare replacem en t p a rts. T h e item s w ith o u t a lpha designators o n the draw ings are f o r reference o n ly , a nd c a n n o t be purchased as spare replacem...

  • Page 402

    Recommended spare parts list description part number brake assembly.............................................. 962010-001 index assembly......... ............................. .......... 187010-001 track 0 assembly............................................... 187174-001 frame assembly.............

  • Page 403

    A-3.

  • Page 404

    A-4.

  • Page 405

    A-5.

  • Page 407: Appendix  B

    Appendix b circuit board schematics and assembly drawings t h is a p p e n d ix contains the c u rre n t c irc u it b o a rd schematics and assembly d ra w in g s f o r th e t m 5 0 0 series o f d isk drives. D ra w in g n u m b e r t itle page n u m b e r 187340-001 r e v l c o n tro l a nd d a ta ...

  • Page 416

    Radio shack, a division of tandy corporation u.S.A.: fort worth, texas 76102 ___________canada: barrie, ontario l4m 4w5__________ tandy corporation australia___________ ____________ belgium_____________ l u c __________ _ 91 kurrajong avenue parc industriel bilston road weonesbury mount druitt, n.S....