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Icom IC-78 Service Manualvice Man

Manual is about: HF Transceiver

Summary of IC-78

  • Page 1

    S-13707mz-c1 © 2000 icom inc. 1-1-32, kamiminami, hirano-ku, osaka 547-0003, japan count on us! Hf tranceiver ic-78 ic-78 up ic-78.

  • Page 2

    Repair notes 1. Make sure a problem is internal before disassembling the transceiver. 2. Do not open the transceiver until the transceiver is disconnected from its power source. 3. Do not force any of the variable components. Turn them slowly and smoothly. 4. Do not short any circuits or electronic ...

  • Page 3

    Table of contents section 1 specifications section 2 inside views section 3 disassembly instructions section 4 circuit description 4 – 1 receiver circuits ................................................................................................................. 4 – 1 4 – 2 transmitter circuit...

  • Page 4

    Section 1 specifications 1 - 1 ■ general • frequency coverage : receive 0.030–29.999999 mhz* 1 transmit 1.600–29.999999 mhz* 2 * 1 guaranteed range: 0.5–29.999999 mhz * 2 guaranteed range: 1.600–1.999999 mhz 3.500–3.999999 mhz 5.000–7.999999 mhz 10.000–29.999999 mhz • mode : usb, lsb, cw, am, rtty (...

  • Page 5

    2 - 1 section 2 inside views filter unit pa unit main unit pll unit ¡ top view (pa and filter units) ¡ bottom view (main and pll units) rx rf preamplifier (q1401, q1402: 2sk2171) tx mixer (q101, q102: 3sk131) 1st lo amplifier (q201: 2sc4673) rx 1st mixer circuit (64.455 mhz) dds gate allay ic (ic6: ...

  • Page 6

    3 - 1 section 3 disassembly instructions • removing the covers remove 14 screws from the top and bottom covers. • removing the front unit and pa cover remove 4 screws from the front panel. Remove 5 screws from the pa cover. • how to connect the coaxial cable connect the coaxial cable as shown below....

  • Page 7

    Section 4 circuit description 4 - 1 4-1 receiver circuits 4-1-1 rf switching circuit (filter and main units) the rf switching circuit leads receive signals to bandpass filters from the antenna connector while receiving. While transmitting, this circuit leads signals from the rf power amplifier to th...

  • Page 8

    4 - 2 the signals from the pre-amplifier circuit, or signals which bypass the pre-amplifier, pass through a low-pass filter (l902, l903, c904–c907). This low-pass filter suppresses signals above 30 mhz to eliminate direct receiving of signals at 64.455 mhz and image interference at 130–160 mhz. The ...

  • Page 9

    4 - 3 4-1-10 ssb/cw demodulator circuits (main unit) in ssb or cw mode, the 2nd if signal from the if amplifier (q1601) is mixed with the bfo signal from the pll unit at the product detector (ic2001) to demodulate the 2nd if sig- nal into af signals. The detected signals (af) from ic2001 (pin 1) are...

  • Page 10

    4 - 4 the amplified signal is applied to the vca (ic2701), and then volume controlled af signal is power-amplified at the af power amplifier (ic2901) to drive the speaker. The af signal is applied to the speaker. 4-2 transmitter circuits 4-2-1 microphone amplifier circuit (main unit) the microphone ...

  • Page 11

    4 - 5 the “for” voltage from the filter unit is applied to ic1701c (pin 9) in the main unit. The “pocv” voltage from the d/a converter (ic3301, pin 2), determined by the rf power setting, is applied to ic1701c (pin 10) as the refer- ence voltage. When the “for” voltage exceeds the “pocv” voltage, al...

  • Page 12

    4 - 6 4-3 pll circuits 4-3-1 general description the pll unit contains 2 dds circuits for generating a 1st lo signal (64.485–94.455 mhz variable) and a bfo frequency (453.5–456.5 khz). The 1st lo pll employs a 1 loop dds pll whose reference oscillator is also used as the 2nd lo signal (64.00 mhz fix...

  • Page 13

    4-4-3 cpu (logic unit) the cpu (ic1) contains an 8-bit cmos cpu, a 60 k-byte rom, a 2 k-byte ram. A 9.8304 mhz clock is used for rapid operation. The cpu controls the operating frequency, mode, function display, etc. The memory channel information is stored in the eeprom (ic2). The icom ci-v network...

  • Page 14

    4 - 8 4-5 power supply circuits 4-5-1 pa unit 4-5-2 logic unit 4-5-3 main unit line hv 14 v description the voltage from an external power supply passed through a fuse (f1). The same voltage as the hv line passed through the switching relay (rl1). Line 8v t8v r8v –5v pat8 t13v r13v description commo...

  • Page 15

    Section 5 adjustment procedures 5 - 1 5-1 preparation before servicing ■ required test equipment dc power supply rf power meter (terminated type) frequency counter rf voltmeter modulation analyzer distortion meter oscilloscope digital multimeter spectram analyzer standard signal generator (ssg) ac m...

  • Page 16

    5 - 2 5-2 pll adjustments reference frequency vco lock voltage 1st lo output level 2nd lo output level bfo output adjustment adjustment adjustment condition measurement value point unit location unit adjust 1 2 3 1 2 1 2 1 1 2 3 • display frequency: any • set c16 as illustration at below. • receivin...

  • Page 17

    5 - 3 2nd lo j1 1 2 1 2 p2 bfo j2 1 2 1st lo j4 1 2 1 2 p3 c7 c6 reference osc level adjustment p1 reference frequency check point c16 reference frequency pre-setting p4 1st lo output level check point p5 bfo check point c165 vco lock voltage adjustment l4 reference freauency adjustment • pll unit.

  • Page 18

    5 - 4 5-3 transmitter adjustments idling current (for driver) (for final amplifier) swr detector transmitter total gain output power ic apc adjustment adjustment adjustment condition measurement value point unit location unit adjust 1 2 1 2 1 2 1 1 • display frequency: 12.23000 mhz • mode : usb • rf...

  • Page 19

    5 - 5 cp4002 ic apc pre-setting j3601 idling current pre-setting r1707 output power adjustment l151 tx total gain adjustment l106 r503 l501 l303 l302 l301 r1720 ic apc adjustment r2701 tx total gain pre-setting r21 idling current adjustment (driver) r24 idling current adjustment (final) j5 swr detec...

  • Page 20

    5 - 6 transmitter adjustments—continued carrier suppression am carrier am modulation cw carrier adjustment adjustment adjustment condition measurement value point unit location unit adjust 1 1 1 2 1 • display frequency: 12.23000 mhz • mode : usb • mic gain : minimum (0) • apply no audio signals to [...

  • Page 21

    5 - 7 cp3701 cw carrier check point r3703 cw carrier adjustment r1730 am carrier adjustment r2321 am modulation adjustment (or am carrier pre-setting) am modulation adjustment (or am carrier pre-setting) r2385 r2303 carrier suppression adjustment • main unit.

  • Page 22

    5 - 8 *this output level of a standard signal generator (ssg) is indicated as ssg’s open circuit. 5-4 receiver adjustments receiver total gain adjustment must perform after transmitter total gain adjustment. Receiver total gain noise blanker adjustment adjustment adjustment condition measurement val...

  • Page 23

    5 - 9 l1621 l1614 rx total gain adjustment l1103 l1202 l1201 r2701 rx total gain pre-setting l1501 cp1501 noise blanker check point l1502 noise blanker adjustment • main unit.

  • Page 24

    5 - 10 5-5 set mode adjustment entering set mode adjustment for rx volume center s meter set mode adjustment for tx filter calibration power meter alc meter adjustment adjustment condition display operation • enter set mode adjustment for rx: 1 turn power off. 2 terminate the [remote] jack with a 3....

  • Page 25

    5 - 11 set mode adjustment —continued swr meter adjustment adjustment condition display operation • connect a 50 Ω dummy load or power meter to [ant] connector. • connect a 100 Ω dummy load or power meter to [ant] connector. 1 2 transmit using an external ptt switch to set swr reference level after ...

  • Page 26

    S.=surface mount sp1 2510000670 speaker vs-50-0827 w3 8900008930 cable opc-885 (p=1 n=10 l=39) w4 8900008930 cable opc-885 (p=1 n=10 l=39) w5 8900006990 cable opc-683 (n:10 l:110) ws1 8970023720 e.Other sx2241 icom shield (1) /fr ep2 6450001230 e.Other hlj0999-01-480 ic1 1140009160 s.Ic hd6433837sd1...

  • Page 27

    [logic board] [logic board] s.=surface mount r103 7030003590 s.Resistor erj3geyj 183 v (18 k Ω ) r104 7030003540 s.Resistor erj3geyj 682 v (6.8 k Ω ) r105 7030003620 s.Resistor erj3geyj 333 v (33 k Ω ) r106 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r107 7030003600 s.Resistor erj3geyj 223 v (22 ...

  • Page 28

    [main unit] [vr board] s.=surface mount r1 7210003040 variable tp96d26-22f-10kbx2-2240 r2 7210003030 variable tp96d00-22f-10kbx2-2240 r4 7030003540 s.Resistor erj3geyj 682 v (6.8 k Ω ) j1 6510022050 s.Connector 10fm-1.0sp-1.9-tf ep1 0910052174 pcb b 5435d j1 6510000190 connector fm214-8ss (p) j2 651...

  • Page 29

    [main unit] [main unit] s.=surface mount d302 1790000620 s.Diode ma77 (tx) d303 1790000620 s.Diode ma77 (tx) d304 1790000620 s.Diode ma77 (tx) d305 1790000620 s.Diode ma77 (tx) d306 1790000620 s.Diode ma77 (tx) d401 1750000430 s.Diode hsb88wstr d501 1160000070 s.Diode dan202k t146 d502 1790001250 s....

  • Page 30

    [main unit] [main unit] s.=surface mount l2901 6140002220 coil lr-270 (tr6x3x2 3a9) l3501 6180000960 coil lal 03na 102k l3502 6180000960 coil lal 03na 102k l4501 6200003950 s.Coil hf50acc 322513-t l4651 6200003950 s.Coil hf50acc 322513-t l4652 6200001830 s.Coil nl 322522t-100j l4653 6200003950 s.Coi...

  • Page 31

    [main unit] [main unit] s.=surface mount r1520 7030003540 s.Resistor erj3geyj 682 v (6.8 k Ω ) r1521 7030003440 s.Resistor erj3geyj 102 v (1 k Ω ) r1522 7030003360 s.Resistor erj3geyj 221 v (220 Ω ) r1523 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r1601 7030003280 s.Resistor erj3geyj 470 v (47 Ω...

  • Page 32

    [main unit] [main unit] s.=surface mount r3002 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r3003 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r3004 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r3005 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r3006 7030003640 s.Resistor erj3geyj 473 v (47 ...

  • Page 33

    [main unit] [main unit] s.=surface mount c843 4030007100 s.Ceramic c1608 ch 1h 560j-t-a c844 4030009580 s.Ceramic c1608 jb 1h 681k-t-a c845 4030010040 s.Ceramic c1608 jb 1h 561k-t-a c846 4030007150 s.Ceramic c1608 ch 1h 151j-t-a c851 4030011600 s.Ceramic c1608 jb 1c 104kt-n c852 4030011340 s.Ceramic...

  • Page 34

    [main unit] [main unit] s.=surface mount c2309 4030011600 s.Ceramic c1608 jb 1c 104kt-n c2310 4030011600 s.Ceramic c1608 jb 1c 104kt-n c2312 4510005810 s.Electrolytic ecev1har47r c2313 4030011600 s.Ceramic c1608 jb 1c 104kt-n c2314 4030011600 s.Ceramic c1608 jb 1c 104kt-n c2315 4510005810 s.Electrol...

  • Page 35

    [pll unit] [main unit] s.=surface mount j4201 6510021720 s.Connector 30flt-sm1-tb j4401 6510021720 s.Connector 30flt-sm1-tb j4501 6450000140 connector hsj0807-01-010 j4502 6510018960 s.Connector b2b-ph-sm3-tb j4651 6450001640 connector tcs5044-01-4111 j4801 6450001130 connector jpj2042-01-110 j5001 ...

  • Page 36

    [pll unit] [pll unit] s.=surface mount r97 7030003440 s.Resistor erj3geyj 102 v (1 k Ω ) r98 7030003440 s.Resistor erj3geyj 102 v (1 k Ω ) r99 7030003440 s.Resistor erj3geyj 102 v (1 k Ω ) r102 7030006080 s.Resistor erj1wyj220u (22 Ω ) r103 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r104 7030003...

  • Page 37

    [pa unit] [pll unit] s.=surface mount c195 4030011340 s.Ceramic c1608 ch 1h 471j-t-a c203 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c222 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c223 4030011600 s.Ceramic c1608 jb 1c 104kt-n c224 4030011600 s.Ceramic c1608 jb 1c 104kt-n c225 4030006940 s.Ceramic c16...

  • Page 38

    [filter unit] [pa unit] s.=surface mount c70 4030005050 s.Ceramic c2012 ch 1h 331j-t-a c71 4030011550 s.Ceramic grm42-6 ch 680j 500pt c72 4030014460 s.Ceramic grm42-6 ch 820j 500pt c73 4030011760 s.Ceramic grm44-1 sl 682j 200pt c74 4030011760 s.Ceramic grm44-1 sl 682j 200pt c75 4030011760 s.Ceramic ...

  • Page 39

    [chassis parts] [filter unit] s.=surface mount c71 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c72 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c73 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c74 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c75 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c76 4030006880 s.Cerami...

  • Page 40

    Mp1 8510013040 2241 mixer case 1 mp25 8510013140 2241 dc-a case 1 f1 5210000080 fuse fgb 20a 1 f2 5210000130 fuse fgb 4a 1 w1 optional product dc power cable opc-025 a 1 mc1 optional product microphone hm-36 1 sp1 2510000670 speaker vs-50-0827 1 ep2 6450001230 snap plate hlj0999-01-480 1 mp1 8210016...

  • Page 41

    7 - 2 mp22 (c) mp26 (c) mp22 (c) mp22 (c) mp22 (c) mp22 (c) mp1 (l) mp3 (l) ds1 (l) ep70 (l) mp23 (f) mp23 (f) mp2 (c) mp2 (l) mp22 (f) mp22 (f) mp12 (c) mp24 (f) mp6 (f) mp2 (f) mp31(c) mp24 (f) mp6 (c) mp6 (c) mp1 (c) mp28 (c) mp22 (c) mp22 (c) mp28 (c) mp31 (c) mp8 (c) mp18 (c) mp22 (c) mp3 (f) m...

  • Page 42

    Section parts list section 8 semi-conductor informations 8-1 transistors name symbol inside view name symbol inside view 2sc1971 none 2sc3133 none b c e b c e 2sd1585k none b e c b e c 2sd1619-t-td db 2sd1664 t100q da b c c e 2sa1576a r fr c b e 2sc4673d-td co c e c b 2sk508 k52 2sk1740-ta ij g s d ...

  • Page 43

    Sqls send mod 13.8v 8v gnd bdt afo fskk key band alc 2 12 7 3 4 11 1 10 6 5 13 8 1 2 4 3 5 6 7 9 11 10 8 12 13 9 1 1 10 2 j201 ws1 ws3 j4001 j1 j701 to filter unit j1 from pll unit j4 gnd 1lo 1lo 1loe 1loe p1 p2 w6 to pa unit j6 w7 p5 p6 w10 to filter unit j3 w11 l3 l5 l2 l6 10 9 1 2 gnd t13v l3 ref...

  • Page 44

    9 - 2 sqls send mod 13.8v 8v gnd bdt afo fskk key band alc 2 12 7 3 4 11 1 10 6 5 13 8 1 2 4 3 5 6 7 9 11 10 8 12 13 9 spe espo spo 1 2 3 4 5 6 7 8 9 10 11 12 13 ext sp j4501 alc j4801 acc j4651 send j4801 remote j5001 elec-key j5101 • bottom view (main unit) the combination of this page and the pre...

  • Page 45

    1 to main unit j9 15 16 1 2 gnd 8v 13v dnb dstb pdat con1 fskk nc 13v 13v pstb pck con2 con0 srst 2nd lo j1 1 2 1 2 to main unit j401 p2 p1 2lo 2lo 2loe 2loe bfo pao j2 j3 1 2 to main unit j2001 p5 bfo bfoe 1st lo j4 1 2 1 2 to main unit j201 p4 p3 1lo 1loe 1 5 10 15 16 2 j12 brown orange red yellow...

  • Page 46

    9 - 4 varistor board the combination of this page and the previous page shows the unit layout in the same configuration as the actual p.C. Board. • bottom view (pll unit) • bottom view (pa unit).

  • Page 47

    6 8 5 4 3 2 1 7 1 2 3 4 5 6 7 8 9 10 1 10 afgl afgl gnd gnd gnd rfgl rfgl gnd ritl ritl gnd sftl sftl gnd 5vl 5vl 5vl 5vl 5vl gnd to logic unit j3 shift rit rf/sql af j1 10 2 9 1 espo afo afo afe gnd espo espo afo afe afe to logic unit j5 j2 gnd gnd 1 2 3 4 5 6 7 8 9 10 afgl gnd gnd rfgl ritl sftl 5...

  • Page 48

    1 2 3 4 7 8 6 8 5 4 3 2 1 7 espo afo afo afe gnd espo espo afo afe afe to phone board j2 to vr board j1 j5 1 9 2 10 gnd gnd gnd gnd gnd afgl rfgl ritl sftl 5vl j3 1 2 10 9 to sensor board +5v sen1 sen2 gnd 1 4 mice afo sqls 8v gnd mic gnd send ud gnd to mic board j2 j4 1 9 2 10 gnd dotk dask voxl av...

  • Page 49

    Antenna j14 1 3 5 7 9 2 4 6 8 10 to main unit j4001 10 9 1 2 l1 l6 l4 l2 for l5 ref l3 t13v gnd j1 j3 p5 p6 to main unit j701 w11 ws3 w10 chassis j2 p4 p3 w9 ws2 to pa unit j7 w8 the combination of this page and the next page shows the unit layout in the same configuration as the actual p.C. Board. ...

  • Page 50

    The combination of this page and the previous page shows the unit layout in the same configuration as the actual p.C. Board. 9 - 8 • bottom view (filter unit).

  • Page 51

    10 - 1 section 10 block diagram main unit q1508 2sc4081 q1509 dta114 afgv to mic ic2702 ta7368f d1901 1ss375 ic2001 ta4101 ic5601 tc4566f af select ic2101a njm2058 ic2801 tc4566 ic2901 la4425 ic2701 m5282fp side tone/beep/tone alms analog sw vca ic2102 tc4w53 agc nbs d1501 1ss375 q1506 fi611 fl-65 q...

  • Page 52

    11 - 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 j3 gnd w4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 j4101 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 j4401 chassis 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 j6 w2 front unit +5v se...

  • Page 53

    Section 12 voltage diagram 12-1 filter, pa and main units up ic-78 voltage diagram 153 210 12 - 1 up ic-78 voltage diagram 158 210 12 - 2 vr board sensor board rit shift r1 10k-b sql/rf af r2 10k-b r4 6.8k gnd gnd gnd gnd gnd sftl 5vl ritl rfgl afgl j1 j1 ud 8v mic mice gnd send afo sqls gnd gnd 10 ...

  • Page 54

    Section 12 voltage diagram 12-1 filter, pa and main units up ic-78 voltage diagram 153 210 12 - 1 up ic-78 voltage diagram 158 210 12 - 2 vr board sensor board rit shift r1 10k-b sql/rf af r2 10k-b r4 6.8k gnd gnd gnd gnd gnd sftl 5vl ritl rfgl afgl j1 j1 ud 8v mic mice gnd send afo sqls gnd gnd 10 ...

  • Page 55

    Repair notes 1. Make sure a problem is internal before disassembling the transceiver. 2. Do not open the transceiver until the transceiver is disconnected from its power source. 3. Do not force any of the variable components. Turn them slowly and smoothly. 4. Do not short any circuits or electronic ...

  • Page 56

    S-13707mz-c1 © 2000 icom inc. 1-1-32, kamiminami, hirano-ku, osaka 547-0003, japan count on us! Hf tranceiver ic-78 ic-78 up ic-78.