Service manual hamamatsu, japan 1.338k-713 k printed in japan 2001.09 011551 ga contents specifications .............................................................................. 3 panel layout .................................................................................. 3 circuit board lay...
2 f-20 important notice this manual has been provided for the use of authorized yamaha retailers and their service personnel. It has been assumed that basic service procedures inherent to the industry, and more specifically yamaha products, are already known and understood by the users, and have the...
3 f-20 rated output power: 20w speaker: 20cm x 1 controls: volume, gain, master vol., treble, middle, bass, ch select switch (a/b) input/output terminals: input, aux in, phones output impedance: 100 Ω (phones) power consumption: 30w/100v (j) 25w/120v (ul,csa) 25w/230v (e,bs) power requirements: u.S....
4 f-20 circuit board layout main 1/2 main 1/2 main 1/2 ac cord power transformer main 2/2 main 2/2 block diagram +b +12v -12v -b op amp ic1 3 1 op amp ic2 3 1 op amp ic1 5 7 op amp ic2 5 7 power amp ic3 1 4 input ch. Select sw ch. A clean ic1. Ic2 ch. A clean ch. B drive ch. B drive +b volume gain m...
5 f-20 disassembly procedure [30] x 4 speaker [b] pre-main unit pre-main unit [a] back board 1. Pre-main unit (time required: about 1 min) 1-1 remove the speaker wires. 1-2 remove the four (4) screws marked [30]. The pre-main unit can then be removed by sliding it backward. (fig.1) 2. Speaker (time ...
6 f-20 main 1/2 main 2/2 [p100], [c] [a120] [p60] [p70] [c80] [a140] [p70] [p60] [p40] [p40] power transformer 4. Main 2/2 circuit board (time required: about 3 min) 4-1 remove the pre-main unit. (see procedure 1) 4-2 remove the screw marked [c80]. The main 2/2 circuit board can then be removed. (fi...
7 f-20 a input ch select a/b volume gain master volume treble a' a middle bass aux in phones a' to speaker from power cord to power transformer to main 2/2 cn5 from power transformer main1/2 circuit board circuit boards main 1/2 (j, u): cna-v733720 1 main 1/2 (h, b): cna-v733730 main 2/2 (j, u): cna...
8 f-20 inspections 1. Preparation to inspect the main unit, the following jigs are required. Cd player headphones before turning the power on, set all the knobs on the panel to "0". Raise the ch select switch to select channel a. 2. Power supply connect the power cord to the suitable power supply so...
F-20 1 parts list guitar amplifier contents overall assembly .................................................................................. 2 pre-main unit ............................................................................................ 4 electrical parts ...............................
F-20 2 overall assembly 60 20 10 c40 c60 c50 c60 c50 c30 c30 b a c20 c70 c90 c80 50 30 c120 c100 c110 overall cabinet assembly pre-main unit [a] speaker back board pre-main unit (see p. 4).
F-20 3 ref no. Part no. Description remarks qty rank rank: japan only *new parts * * * * * * * * * 10 20 20 20 20 30 50 60 60 60 c10 c20 c30 c40 c50 c60 c70 c80 c90 c100 c110 c120 a b -- -- -- -- v 6 9 5 4 6 0 0 -- -- -- -- vn347600 e t5 0 0 040 -- -- -- v 6 9 5 4 6 0 0 -- v 5 9 6 9 0 0 0 2 1 7 7 0 ...
F-20 4 a10 a70 a60 a40 a10 a30 a80 a90 a20 p60 p40 p60 p30 p75 p70 p50 p10 p20 p90 p80 a50 p100 p120 p110 a100 a110 a130 a140 a120 pre-main unit.
F-20 5 ref no. Part no. Description remarks qty rank rank: japan only *new parts * * * * * * * * * * * * * * * * * * * * * * * p10 p20 p30 p30 p30 p30 p40 p50 p60 p70 p75 p80 p90 p100 p110 p120 a10 a10 a20 a30 a40 a50 a50 a50 a60 a70 a70 a70 a70 a80 a90 a100 a110 a120 a130 a140 -- -- -- -- v6954800 ...
Ref no. Part no. Description remarks qty rank f-20 6 rank: japan only *new parts electrical parts * * * * * * * * c01 c02 c03 c04 c05 c06 c07 c08 c09 c10 c11 c12 c13 c14 c15 c16 c17 c18 c19 c20 c21 c22 c23 c24 c25 c26 c27 c28 c29 c30 c31 c32 c33 c34 c35 c36 c37 cn1 cn2 cn3 d01 d02 db1 fz1 fz1 ic1 ic...
F-20 7 ref no. Part no. Description remarks qty rank rank: japan only *new parts * * * * * * * * * * * * * * * r10 r11 r12 r13 r14 r15 r16 r17 r18 r19 r20 r21 r22 r23 r24 r25 -27 r28 r29 r30 r31 r32 r33 sw2 tr1 vr1 vr2 vr3 vr4 vr5 vr6 zd1 zd2 cn45 t1t2 t3t4 hf456330 hf456100 hf456100 hf458100 hf4561...
A b c d e f g h 1 2 3 4 5 f-20 f-20 f-20 overall circuit diagram note: see parts list for details of circuit board component parts. Trans former main 1/2 main 2/2 volume gain master ch select a/b power on/off input middle bass treble aux in phones 4 Ω speaker op amp op amp op amp op amp op amp op am...
