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Icom IC-R75 Service Manual

Manual is about: Communications Receiver

Summary of IC-R75

  • Page 1

    Service manual communications receiver.

  • Page 2

    This service manual describes the latest service information for the ic-r75 at the time of publication. Never connect the receiver to an ac outlet or to a dc power supply that uses more than 16 v. Such a connection could cause a fire hazard and/or electric. Do not expose the receiver to rain, snow o...

  • Page 3

    Table of contents section 1 specifications section 2 inside views section 3 circuit description 3-1 receiver circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1 3-2 pll circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

  • Page 4: Section 1

    1 - 1 m general • frequency range : * 1 specifications guaranteed for 0.1 – 29.99 mhz and 50 – 54 mhz * 2 specifications guaranteed for 0.1 – 29.99 mhz • mode : ssb (lsb, usb), am, fm, cw, rtty, s-am • receive system : triple-conversion superheterodyne • intermediate frequencies : may differ accordi...

  • Page 5: Section 2

    2 - 1 section 2 inside views 2nd if filter (fi761: fl-272) 3rd lo circuit 3rd mixer circuit (ic811) bfo circuit 2nd if circuit pll ic (ic21) noise blaker circuit vco circuit bfo mixer circuit (ic1101) bandpass filter fuse (3a) main unit pll unit back up battery (bt 1521) 3rd if filter (fi851) 2nd mi...

  • Page 6

    Section 3 circuit description 3 - 1 3-1 receiver circuits 3-1-1 rf switching circuit (main unit) the ic-r75 has two antenna connectors. Rf signals enter either the [50 Ω ant.] or [450 Ω ant.] connector. Rf signals from the [50 Ω ant.] connector are applied to the antenna switching circuit (rl121), a...

  • Page 7

    3 - 2 3-1-3 pre-amplifier circuit (main unit) the pre-amplifier circuit uses low noise junction fets (q381, q382) or wideband amplifier (ic391) to provide gain over a wide frequency range. When the [p.Amp] switch is turned “preamp 1”, the signals from the rf filter are amplified by the junction fets...

  • Page 8

    3 - 3 when the [fil] switch is turned “2f3k”, the filter is selected fi761 which covering the 2.4 khz bandwith. When the [fil] switch is turned “2fop”, the filter is selected an optional filter. When the [fil] switch is turned “2fth”, the signal from the 2nd if amplifier bypass the crystal bandpass ...

  • Page 9

    3 - 4 the fm detector outputs “fmnl” signal from ic1001, pin 14 is applied to the cpu (logic unit; ic101, pin 94) to control the noise squelch level. (3) am demodulator circuit the am demodulater circuit (ic2001) has the envelope detect function and the synchronous detect function. An am detector (i...

  • Page 10

    3 - 5 the oscillated signal at the vco1 and vco2 circuit is ampli- fied at the lo-amplifier (pll unit; q91), and passes through the low-pass filter (pll unit; q92, d91, d92, l91, l93, c96–c100, c102, c103) to supperss high harmonic compo- nents. The low-pass filter controlls the cut-off frequency of...

  • Page 11

    3 - 6 the cpu has the clock function. Thus, the cpu and the clock function have the crystal separately. The cpu has the 9.8304 mhz crystal (x112) for the cpu clock, and then the oscillated 9.8304 mhz signal is applied to the ic101, pin 7 and 8. The clock function has the 32.768 khz crystal (x111). T...

  • Page 12

    3 - 7 3-5 port allocations 3-5-1 cpu (logic unit; ic101) pin number 1 9 11 12 14 15 16 17 18 19 21 22 23 24 25 26 36 37 38 39 40 41 42 43 44 45 46 47 48 port name key6 cres pwrk dud dast rstb istb astb ecs mck mdat pck pst1 pdat pst2 pst3 ssbk cwk amk fmk filk tsk prek attk nrk anfk nbk agck vmk des...

  • Page 13

    4 - 1 section 4 adjustment procedures 4-1 preparation ‘ ‘ required test equipment ‘ ‘ connection equipment dc power supply frequency counter audio generator dc voltmeter grade and range output voltage : 13.8 v dc current capacity : 2 a or more frequency range : 0.1–60 mhz frequency accuracy : ±1 ppm...

  • Page 14

    4 - 2 4-2 pll adjustment reference frequency vco voltage 1st lo voltage 3rd lo voltage 3rd lo frequency bfo voltage adjustment adjustment adjustment condition measurement value point unit location unit adjust 1 2 1 2 3 4 1 1 1 1 2 • displayed frequency : 29.99999 mhz • mode : usb • displayed frequen...

  • Page 15

    4 - 3 p201 bfo voltage check point p151 3rd lo frequency check point p1 reference frequency check point p91 1st and 3rd lo voltage check point c76 vco voltage adjustment l2 reference frequency adjustment (for output frequency is 60.0000 mhz) hcp71 vco voltage check point c86 l5 reference frequency a...

  • Page 16

    4-3 receiver adjustments 4 - 4 receiver sensitivity 1st mixer balance adjustment adjustment adjustment condition measurement value point unit location unit adjust 1 2 1 • displayed frequency : 14.10000 mhz • mode : usb • preamp1 : on • ant select : ant1 • agc : fast • noise blanker : off • rf/sql : ...

  • Page 17

    Receiver adjustments (continued) 1st if filter receiver total gain adjustment adjustment adjustment condition measurement value point unit location unit adjust 1 1 2 • displayed frequency : 14.10000 mhz • mode : fm • preamp1 : on • if filter1 : 15 khz • if filter2 : 6 khz • set an ssg as frequency :...

  • Page 18

    4 - 6 ext sp jack noise blanker check point after apply the noise signal noise blanker adjustment before apply the noise signal r736 • main unit cp731 noise blanker check point before apply the noise signal • noise blanker adjustment after apply the noise signal • pre-set to center before apply the ...

  • Page 19

    4 - 7 4-4 set mode adjustment entering adjustment set mode pbt volume s-meter filter calibration adjustment adjustment condition display operation 1 1 2 3 4 1 2 • turn power off • connect a terminator to the [remote] connector on the rear panel. • while pushing “set[ant] and “clock” keys, and turn p...

  • Page 20: Section 5 Parts List

    S.=surface mount r131 7210003040 variable tp96d26-22f-10kbx2-2240 r141 7210003030 variable tp96d00-22f-10kbx2-2240 r143 7030003540 s.Resistor erj3geyj 682 v (6.8 k Ω ) j101 6510020710 s.Connector 52793-1090 ep1 0910051172 pcb b 5271b l121 6200003950 s.Coil hf50acc 322513-t r121 7030006070 s.Resistor...

  • Page 21

    5 - 2 s.=surface mount r262 7030003540 s.Resistor erj3geyj 682 v (6.8 k Ω ) r271 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r272 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r273 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r274 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r275 7030003640 ...

  • Page 22

    S.=surface mount q71 1530002850 s.Transistor 2sc4116-bl (te85r) q81 1530002850 s.Transistor 2sc4116-bl (te85r) r11 7030000320 s.Resistor mcr10ezhj 330 Ω (331) r12 7030003360 s.Resistor erj3geyj 221 v (220 Ω ) r21 7030000320 s.Resistor mcr10ezhj 330 Ω (331) r22 7030003360 s.Resistor erj3geyj 221 v (2...

  • Page 23

    5 - 4 s.=surface mount d762 1790000620 s.Diode ma77 (tx) d763 1790000620 s.Diode ma77 (tx) d764 1790000620 s.Diode ma77 (tx) d771 1790000620 s.Diode ma77 (tx) d772 1790000620 s.Diode ma77 (tx) d773 1790000620 s.Diode ma77 (tx) d774 1790000620 s.Diode ma77 (tx) d781 1790000620 s.Diode ma77 (tx) d782 ...

  • Page 24

    S.=surface mount r261 7030003320 s.Resistor erj3geyj 101 v (100 Ω ) r281 7030003320 s.Resistor erj3geyj 101 v (100 Ω ) r301 7030003320 s.Resistor erj3geyj 101 v (100 Ω ) r321 7030003320 s.Resistor erj3geyj 101 v (100 Ω ) r341 7030003320 s.Resistor erj3geyj 101 v (100 Ω ) r361 7030006260 s.Resistor e...

  • Page 25

    5 - 6 s.=surface mount r883 7030003360 s.Resistor erj3geyj 221 v (220 Ω ) r884 7030003510 s.Resistor erj3geyj 392 v (3.9 k Ω ) r885 7030003560 s.Resistor erj3geyj 103 v (10 k Ω ) r891 7030003560 s.Resistor erj3geyj 103 v (10 k Ω ) r892 7030003320 s.Resistor erj3geyj 101 v (100 Ω ) r893 7030003480 s....

  • Page 26

    S.=surface mount c223 4030007140 s.Ceramic c1608 ch 1h 121j-t-a c224 4030007130 s.Ceramic c1608 ch 1h 101j-t-a c225 4030006850 s.Ceramic c1608 jb 1h 471k-t-a c226 4030006870 s.Ceramic c1608 jb 1h 222k-t-a c227 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c228 4030006860 s.Ceramic c1608 jb 1h 102k-t-a c...

  • Page 27

    5 - 8 s.=surface mount c882 4030011600 s.Ceramic c1608 jb 1c 104kt-n c891 4030011600 s.Ceramic c1608 jb 1c 104kt-n c892 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c893 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c894 4030011600 s.Ceramic c1608 jb 1c 104kt-n c895 4030007050 s.Ceramic c1608 ch 1h 220j-t-...

  • Page 28

    S.=surface mount j884 6450001560 connector pd-72 j1081 6510007020 connector tmp-j01x-v6 j1221 6510018970 s.Connector b4b-ph-sm3-tb j1231 6510019970 s.Connector 52808-1090 j1271 6510019190 s.Connector 52365-0891 j1311 6450001800 connect jpj1044-01-010 j1321 6450000140 connector hsj0807-01-010 j1351 6...

  • Page 29

    5 - 10 s.=surface mount r81 7030003560 s.Resistor erj3geyj 103 v (10 k Ω ) r83 7030003480 s.Resistor erj3geyj 222 v (2.2 k Ω ) r85 7030003430 s.Resistor erj3geyj 821 v (820 Ω ) r86 7030003350 s.Resistor erj3geyj 181 v (180 Ω ) r91 7030003260 s.Resistor erj3geyj 330 v (33 Ω ) r92 7030003550 s.Resisto...

  • Page 30

    S.=surface mount c99 4030006930 s.Ceramic c1608 ch 1h 020c-t-a c100 4030007080 s.Ceramic c1608 ch 1h 390j-t-a c101 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c102 4030007020 s.Ceramic c1608 ch 1h 120j-t-a c103 4030006970 s.Ceramic c1608 ch 1h 060d-t-a c104 4030006880 s.Ceramic c1608 jb 1h 472k-t-a c1...

  • Page 31: Section 6

    6 - 1 section 6 mechanical parts and disassembly ref. No. Oder no. Description qty. J1 6510000370 connector mr-ds 1 w3 8900007000 cable opc-684 1 w4 8900007000 cable opc-684 1 w5 8900007000 cable opc-684 1 w6 8900007000 cable opc-684 1 mp1 8010017710 2240 main chassis 1 mp2 8110006700 2240 u-cover 1...

  • Page 32

    6 - 2 unit abbreviation (c): chassis parts, (p): pll unit, (m): main unit, (f): front unit, (d): display unit mp27 (f) mp37 (f) mp26 (f) sp1 (f) mp2 (f) mp1 (f) mp11 (f) mp10 (f) mp16 (f) mp15 (f) mp13 (f) mp38 (f) mp18 (f) mp14 (f) mp7 (f) mp9 (f) mp17 (f) mp12 (f) mp4 (f) mp5 (f) mp24 (f) ep2 (d) ...

  • Page 33: Section 7

    Section 7 semi-conductor information 7 - 1 2sa1576 r (symbol: fr) 2sc4081 r (symbol: br) 2sc4116 bl (symbol: ll) 2sc4405 3 (symbol: oy3) 2sd1664 q (symbol: da) 2sk1740 (symbol: ij) 2sk2171 4 (symbol: km) 2sk508 k52 (symbol: k52) dtc114 eu (symbol: 14) xp4601 (symbol: 5c) 2sk882 gr (symbol: tgr) 2sc4...

  • Page 34: Section 8

    8 - 1 8-1 phone and vr boards section 8 board layouts r122 r121 c123 c122 c121 l121 • vr board r131 r141 j101 j101 to logic board j451 r143 gnd gnd gnd gnd gnd pb2l pb1l rfgl afgl 5vl 1 10 • phone board top view.

  • Page 35

    8 - 2 • phone board bottom view j121 j101 j101 to logic board j471 gnd afe afe afe espo espo espo afo afo afo 10 1.

  • Page 36: •

    8 - 3 8-2 display board • top view ds1 1 ds21 ds31 ds41 ds51 ds61 ds71 ds12 ds22 ds32 ds42 ds52 ds62 ds72 ds13 ds23 ds33 ds43 ds53 ds63 ds73 ds81 ds82 ds83.

  • Page 37: •

    • bottom view 8 - 4 j101 r1 1 r21 r31 r41 r51 r61 r71 r81 r12 r22 r32 r42 r52 r62 r72 r82 c101 q11 q21 q31 q41 q51 q61 q71 q81 ic101 j101 to logic board j411 14v dimv com4 com2 v1 v3 cl2 m gnd gnd com3 com1 v2 cl1 do h5vl 2 16 1 15.

  • Page 38

    8-3 logic board 8 - 5 r257 r256 r255 r254 c255 c254 c253 c252 c251 c206 c204 c205 c256 r1 12 c231 r261 r260 r121 r123 r127 r129 r131 w163 w162 w161 r163 r162 r161 r142 r144 r146 r148 r150 r152 r154 r171 r173 r175 r177 r179 r280 r281 r284 r291 r289 r287 r272 r274 r276 r278 r286 r279 r282 r283 r292 r2...

  • Page 39

    8 - 6 c116 c117 c72 c75 c79 l204 q82 q93 c123 d72 r236 r83 c325 c92 c94 r93 c118 r94 r102 c101 c103 c100 r98 c105 r96 r97 d91 r95 d1 r107 r26 r37 r27 r38 r28 r39 r29 r40 r30 r41 r31 r42 r32 r43 r33 r44 r34 r45 r35 c37 c44 c38 l23 l26 r46 r25 r36 r24 r23 r235 c327 c110 c23 w18 d92 c99 ep8 ep5 ep4 ep2...

  • Page 40

    8-5 main unit 8 - 7 c1351 ic1361 l131 1 ic1391 q1381 l141 1 c1422 c1417 c1418 ic1771 c1754 ic1401 c1420 l1412 c1414 c1412 c361 l362 r152 r101 q131 1 d1412 d1413 q1382 r 111 c1362 c1364 c131 1 d131 1 c1382 c1381 c141 1 c1416 r1413 r1412 c1393 r1312 c1321 r1772 c1771 r1313 r1314 c161 c162 c164 r172 r1...

  • Page 41: Section 9

    9 - 1 section 9 block diagram ant2 (450 Ω ) 450 Ω to 50 Ω 1.6mhz 1.6mhz 60mhz ant1 (50 Ω ) chassis unit rl121 mz-12hg rl141 mz-12hg 10db 2mhz 130mhz bw=15khz r14v reg xtal bpf if amp xtal bpf xtal bpf optional xtal bpf nb gate if amp lpf att nb det agc amp agc amp noise amp noise amp noise amp gate ...

  • Page 42: Section 10

    R211 1 k r210 1 k r209 1 k r208 1 k r206 1 k r205 1 k r203 1 k r204 1 k r202 1 k r201 1 k r271 47 k r273 47 k r275 47 k r277 47 k r279 47 k r281 47 k r283 47 k r285 47 k r287 47 k r272 47 k r274 47 k r276 47 k r278 47 k r282 47 k r280 47 k r284 47 k r286 47 k afgl rfgl pb1l pb2l fmnl pwrs bpck rxs a...

  • Page 43: Right Side

    R272 47 k r274 47 k r276 47 k r278 47 k r282 47 k r280 47 k r284 47 k r286 47 k r288 47 k r290 47 k r292 47 k l1 display board 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 j411 52808-1690 m h5vl do cl2 14v r422 100 k r421 470 r423 10 k q421 dta144eu pwrs pwrc pwrs pw...

  • Page 44: Left Side

    R211 1 k r210 1 k r209 1 k r208 1 k r206 1 k r205 1 k r203 1 k r204 1 k r202 1 k r201 1 k r271 47 k r273 47 k r275 47 k r277 47 k r279 47 k r281 47 k r283 47 k r285 47 k r287 47 k r272 47 k r274 47 k r276 47 k r278 47 k r282 47 k r280 47 k r284 47 k r286 47 k afgl rfgl pb1l pb2l fmnl pwrs bpck rxs a...

  • Page 45

    10 - 2 p91 tmp-p01x-a1 5v j91 tbp-p01x-a1 r102 18 c95 0.0047 c101 0.0047 c104 0.0047 l92 56 nh l93 68 nh r95 47 c99 2 p c97 8 p r100 3.9 k r50 1 k r51 1 k r52 1 k r53 1 k r110 220 duls lof2 vcos c115 0.0047 vss 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 etco0 75 sysclko vss 10...

  • Page 46: Complete View

    C137 2.2 c1361 2.2 c1411 0.1 l1411 220 µ h r 1 r 1 c1412 47 c384 0.1 r386 100 d382 ma77 d372 ma77 espo ispo espo ispo q381 2sk2171 4 l384 330 µ h r372 100 r371 100 c372 10 p c371 0.1 l383 lr-171 l381 lr-86 l371 220 µ h l382 1.5 µ h c386 0.1 r361 470 l362 330 µ h l361 330 µ h r362 470 d381 ma77 d371 ...

  • Page 47: Complete View

    Q801 2sc4081 r r801 1 k c801 0.1 r802 100 c811 0.0047 r817 2.7 k r816 2.7 k r814 3.3 k r813 470 r812 470 r815 3.3 k r821 3.3 k r820 1 k c813 0.1 c818 0.1 c841 0.0047 r823 10 r822 10 r825 ntccm16083nh 681kc r811 1.5 k fi761 fl-272 d761 ma77 d763 ma77 d762 ma77 d764 ma77 r761 2.2 k r763 220 r762 220 r...

  • Page 48: Complete View

    L911 ls-450 q912 2sc4081 r r914 10 k r915 10 k c914 2.2 l891 ls-450 r892 100 c892 0.0047 q891 3sk131 mas r893 2.2 k c893 0.0047 r894 22 k c894 0.1 r895 330 l1001 220 µ h c1010 0.1 q801 2sc4081 r r801 1 k c801 0.1 r802 100 c811 0.0047 r817 2.7 k r816 2.7 k r814 3.3 k r813 470 r812 470 r815 3.3 k r821...

  • Page 49: Left Side

    L911 ls-450 q912 2sc4081 r r914 10 k r915 10 k c914 2.2 l891 ls-450 r892 100 c892 0.0047 q891 3sk131 mas r893 2.2 k c893 0.0047 r894 22 k c894 0.1 r895 330 l1001 220 µ h c1010 0.1 q801 2sc4081 r r801 1 k c801 0.1 r802 100 c811 0.0047 r817 2.7 k r816 2.7 k r814 3.3 k r813 470 r812 470 r815 3.3 k r821...

  • Page 50

    6-9-16, kamihigashi, hirano-ku, osaka 547-0002, japan phone : 06 6793 5302 fax : 06 6793 0013 communication equipment himmelgeister str. 100, d-40225 düsseldorf, germany phone : 0211 346047 fax : 0211 333639 url : http://www.Icomeurope.Com unit 9, sea st., herne bay, kent, ct6 8ld, u.K. Phone : 0122...

  • Page 51

    6-9-16, kamihigashi, hirano-ku, osaka, 547-0002, japan a-5580i-s © 1999 by icom inc..