Icom IC-R75 Service Manual Download Page 5

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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 mixer circuit

1st IF filter (FI701)

1st mixer circuit

Summary of Contents for IC-R75

Page 1: ...SERVICE MANUAL COMMUNICATIONS RECEIVER...

Page 2: ...910051123 PCB B 5274C IC R75 PLL UNIT 1 pieces 8810005770 Screw Bih M3x8 ZK IC R75 Chassis 10 pieces Addresses are provided on the inside back cover for your convenience 1 Make sure a problem is inter...

Page 3: ...EDURES 4 1 PREPARATION 4 1 4 2 PLL ADJUSTMENT 4 2 4 3 RECEIVER ADJUSTMENT 4 4 4 4 SET MODE ADJUSTMENT 4 7 SECTION 5 PARTS LIST SECTION 6 MECHANICAL PARTS AND DISASSEMBLY SECTION 7 SEMI CONDUCTOR INFOR...

Page 4: ...Hz 6 dB less than 30 0 kHz 40 dB Audio output power More than 2 0 W at 10 distortion with an 8 load Antenna impedance 50 or 450 Squelch sensitivity threshold Preamplifiers are OFF 1 Preamplifier 1 is...

Page 5: ...it 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 fi...

Page 6: ...e signals are applied to the low pass filter consisting of C170 C175 L171 L173 via the limitter circuit D141 D142 A diode is removed at the entrance of the low pass filter This device prevents the dio...

Page 7: ...ss filter FI 461 to suppress out of band signals The filtered signal is amplified at a 1st IF amplifier Q471 and then applied to a 2nd mixer circuit D491 3 1 5 2ND MIXER AND IF CIRCUITS MAIN UNIT The...

Page 8: ...e filter is selected FI871 which covering the 15 kHz bandwith When the FIL switch is turned 3FOP the filter is selected an optional crystal bandpass filter When the mode is selected SSB mode the filte...

Page 9: ...the buffer amplifier Q1031 to convert the impedance The amplified IF signal is detected at the AGC detector D1061 via the C1061 and enters the base of the AGC amplifier Q1063 to control the voltage on...

Page 10: ...1 on the PLL unit and is applied to the 10 bits DDS IC PLL unit IC201 pin 7 for the clock signal to produce the 455 kHz BFO signal The BFO signal is applied to the D A converter circuit and passes thr...

Page 11: ...the BATT signal from the battery MAIN unit BT1521 is applied to the Q511 and then Q512 is OFF The output signal is applied to the CPU IC101 pin 31 as B5V signal to keep on working the clock function T...

Page 12: ...h Input port for the ANF switch Input port for the NB switch Input port for the AGC switch Input port for the V M switch Pin number 49 50 51 52 53 54 55 56 57 63 77 78 79 80 81 82 83 84 90 91 92 93 94...

Page 13: ...ce 50 k V DC or better EQUIPMENT Oscilloscope AC millivoltmeter External speaker Standard signal generator SSG GRADE AND RANGE Frequency range DC 20 MHz Measuring range 0 01 20 V Measuring range 10 mV...

Page 14: ...z Mode USB Displayed frequency 9 4615 MHz Mode FM Displayed frequency 14 100000 MHz Mode USB Displayed frequency 14 100000 MHz Mode AM PLL PLL PLL PLL PLL PLL Connect the fre quency counter to P1 Conn...

Page 15: ...rence 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...

Page 16: ...MP1 OFF set an SSG level as OFF Receiving Rear Panel Rear panel Connect the AC milli volt meter to the EXT SP jack with an 8 load Connect an oscillo scope to the EXT SP jack with 8 load Pre set to cen...

Page 17: ...4 kHz IF FILTER2 2 4 kHz Set an SSG as Frequency 14 10150 MHz Level 500 V 54 dB Modulation OFF Set an SSG level as OFF Receiving Rear panel Rear panel Connect the AC milli volt meter to the EXT SP ja...

Page 18: ...CONDITION MEASUREMENT VALUE POINT UNIT LOCATION UNIT ADJUST 1 2 Displayed frequency 14 10000 MHz Mode USB Noise Blanker OFF PREAMP1 ON Set an SSG as Frequency 14 10000 MHz Level 18 V 25 dB Modulation...

Page 19: ...wn PBT SET on the display Then advance to the following setting or push UP key to scroll the display Push SET ANT key to set the PBT level When the PBT level is true shown GOOD on the display When S0...

Page 20: ...V 1 k R149 7030003440 S RESISTOR ERJ3GEYJ 102 V 1 k R150 7030003440 S RESISTOR ERJ3GEYJ 102 V 1 k R151 7030003440 S RESISTOR ERJ3GEYJ 102 V 1 k R152 7030003440 S RESISTOR ERJ3GEYJ 102 V 1 k R153 7030...

Page 21: ...030008560 S CERAMIC C1608 CH 1H 300J T A C201 4030008630 S CERAMIC C1608 JF 1C 104Z T A C202 4030008630 S CERAMIC C1608 JF 1C 104Z T A C203 4030008630 S CERAMIC C1608 JF 1C 104Z T A C204 4030008630 S...

Page 22: ...0000130 S IC TD62783AF TP1 IC1751 1120002510 S IC DS14C232TM IC1771 1130005720 S IC TC7W04F TE12L IC2001 1110004940 S IC MC13022ADWR3 Q151 1590000680 S TRANSISTOR DTC114EUA T106 Q381 1560000720 S FET...

Page 23: ...NL 322522T 100J L302 6200003020 S COIL NL 322522T R33J 3 L303 6200003010 S COIL NL 322522T R27J 3 L304 6200003020 S COIL NL 322522T R33J 3 L305 6200003030 S COIL NL 322522T R47J 3 L321 6200001830 S CO...

Page 24: ...STOR ERJ3GEYJ 104 V 100 k 5 5 REF ORDER DESCRIPTION NO NO MAIN UNIT R732 7030003520 S RESISTOR ERJ3GEYJ 472 V 4 7 k R733 7030003320 S RESISTOR ERJ3GEYJ 101 V 100 R734 7030003320 S RESISTOR ERJ3GEYJ 10...

Page 25: ...7 k R1259 7030003520 S RESISTOR ERJ3GEYJ 472 V 4 7 k R1260 7030003320 S RESISTOR ERJ3GEYJ 101 V 100 R1261 7030003480 S RESISTOR ERJ3GEYJ 222 V 2 2 k REF ORDER DESCRIPTION NO NO MAIN UNIT R1262 703000...

Page 26: ...00 S CERAMIC C1608 JB 1C 104KT N C397 4030011600 S CERAMIC C1608 JB 1C 104KT N 5 7 REF ORDER DESCRIPTION NO NO MAIN UNIT C401 4030011600 S CERAMIC C1608 JB 1C 104KT N C411 4030007080 S CERAMIC C1608 C...

Page 27: ...30006900 S CERAMIC C1608 JB 1E 103K T A C1352 4030006900 S CERAMIC C1608 JB 1E 103K T A C1353 4510004510 ELECTROLYTIC 25 MV 470 HC C1361 4510005860 S ELECTROLYTIC ECEV1HA2R2SR C1362 4030011600 S CERAM...

Page 28: ...J L93 6180002970 S COIL NL 322522T 068J L94 6200001830 S COIL NL 322522T 100J L151 6200003130 S COIL NL 322522T 120J L152 6200003140 S COIL NL 322522T 150J L153 6200001830 S COIL NL 322522T 100J L201...

Page 29: ...ESISTOR ERJ3GEYJ 102 V 1 k R231 7030003440 S RESISTOR ERJ3GEYJ 102 V 1 k R232 7030003440 S RESISTOR ERJ3GEYJ 102 V 1 k REF ORDER DESCRIPTION NO NO PLL UNIT R233 7030003440 S RESISTOR ERJ3GEYJ 102 V 1...

Page 30: ...0 S CERAMIC C1608 JB 1H 472K T A C202 4030006850 S CERAMIC C1608 JB 1H 471K T A C203 4030007120 S CERAMIC C1608 CH 1H 820J T A C204 4030009490 S CERAMIC C1608 JB 1H 821K T A C205 4030007070 S CERAMIC...

Page 31: ...6030 2240 Front cover 1 MP2 8930001770 SP net 1 MP4 8930048740 2240 9 Key 1 MP5 8930048730 2240 6 Key 1 MP6 8930048750 2240 20 Key 1 MP7 8930048710 2240 Brake plate 1 MP9 8930049370 2240 Brake sheet 1...

Page 32: ...1 D MP3 D DS101 D MP2 D DISPLAY UNIT MP24 F W4 F W3 F MP10 C EP2 F MP15 C MP382 M MP442 M MP15 C MP13 C MP13 C MP13 C MP13 C MP20 C J1 C MP19 C MP17 C MP18 C MP3 P MP9 P MP12 P MP16 C MP16 C PLL UNIT...

Page 33: ...K131 MAS Symbol V11 DTA114 EU Symbol 14 DTA144 EU Symbol 16 XP4311 Symbol 3X TRANSISTOR AND FET S B E C E C B E C B D G S D G S 2SC4117 BL Symbol CL B E C B E C B C E C B C E C B E C B E C B E C E1 C2...

Page 34: ...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 VI...

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 DS11 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: ...4 J101 R11 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 H...

Page 38: ...51 X111 IC101 X112 IC231 C203 C201 C105 C202 R253 R252 R251 R258 R259 R231 C111 C104 C103 R201 R202 R203 R204 R205 R206 C112 C113 C114 C101 C352 IC401 IC351 R381 EP527 EP525 EP523 EP521 EP526 EP524 EP...

Page 39: ...C76 L93 MP2 MP1 C86 J4 J3 MP5 J91 C106 C74 L71 L72 L91 L92 C119 L25 C24 IC23 L22 L27 L24 IC21 L4 L5 L1 J151 MP8 MP11 L153 C215 L203 C165 J1 IC22 L81 Q81 L82 C84 L94 Q71 R75 R85 R116 C124 R79 C83 C78...

Page 40: ...231 L181 L183 L282 L261 L263 L242 D261 Q151 C151 C135 C134 C136 R141 C163 C341 C333 C322 C342 R171 C176 C174 C350 R321 R281 C290 R261 R241 C248 C385 Q383 R386 C433 C432 C435 C436 C434 C230 C269 C246 C...

Page 41: ...55kHz Q3 DTC114EU D1 DAN222 UNLC ULD DULS IC1751 DS14C232TM IC1771 TC7W04F Q1771 2SA1576 R Q1772 2SC4081 R D1771 1SS355 Q1311 2SC4081 R D1311 1SS355 CI V CPU IC401A TC74HC04AF IC401B TC74HC04AF Q401 X...

Page 42: ...5320SI 2 7 R231 100 k C231 0 1 H5VL RFGV AFGV DCK DUD C102 0 1 R223 10 k R224 10 k R225 10 k C221 0 1 R221 470 COM1 COM2 COM3 COM4 V3 V2 V1 V3 V2 V1 R161 47 k W163 W162 W161 R155 1k R153 1k R151 1k R1...

Page 43: ...BL R12 220 R21 330 R22 220 R31 330 R32 220 DS23 TLYE1002 DS33 TLYE1002 Q21 2SC4116 BL Q81 2SC4116 BL DIMV R11 330 DS13 TLYE1002 Q11 2SC4116 BL CL1 V3 V2 V1 GND GND COM1 COM2 COM3 COM4 L2 O STB NT RES...

Page 44: ...Y46 85 Y45 86 Y44 87 Y43 88 Y42 89 Y41 90 Y40 91 Y39 92 Y38 93 Y37 94 Y36 95 Y35 96 Y34 97 Y33 98 Y32 99 IC101 HD66100F H5VL V1 V3 V2 CL1 CL2 DO M C101 0 1 SE15 SE14 SE13 SE12 SE11 SE10 SE1 SE2 SE3 SE...

Page 45: ...P C121 0 1 C125 47 P R115 82 k R80 12 k R116 33 k L94 10 H R117 68 Q97 2SC4117 BL C124 0 1 L83 LW 25 L81 LW 25 L73 LW 25 R72 680 k R73 33 C85 470 P C87 4 P L82 E544GN 110248 Q21 2SC4117 BL R49 1 k R55...

Page 46: ...7 H 14V R8V ATTC ANTC C309 0 1 L305 0 47 H D302 MA77 D322 MA77 L326 0 22 H R321 100 C330 56 P C332 0 01 C331 22 P B7 L301 10 H L302 3 3 H L303 0 27 H C306 180P C308 100P C301 0 1 C302 8 P C303 180 P C...

Page 47: ...D1412 1SS302 C1419 0 1 C1420 10 L1412 330 H D1413 MA8051 M R1414 100 R1416 100 C1421 0 1 C1418 47 H5V 14V 8V H5V 14V 8V 5V FUSE HOLDER F1352 S N5054 01 F1353 S N5054 R1382 2 2 k R1381 47 k Q1381 2SD16...

Page 48: ...0 C1754 10 C1 V C1 C2 C2 V T2O R2I VCC GND T1O R1I R1O T1I T2I R2O 1 2 3 4 5 6 7 8 16 15 14 13 12 10 11 9 5 9 4 8 3 7 2 6 1 IC1751 DS14C232TM SS CIV CIVE IC1771A TC7W04F Q1771 2SA1576 R C1771 0 1 IC17...

Page 49: ...201M S00B C111 1 ANT1 C131 33 P C134 82 P C136 56 P RL141 MZ 12D K L151 330 H Q151 DTC114EU R152 10 k C152 0 1 D141 1SS302 D142 1SS302 R141 2 2 k R142 470 R144 68 R143 330 C141 0 01 C164 0 1 L162 4 7...

Page 50: ...france com Corporate Headquarters 2380 116th Avenue N E Bellevue WA 98004 U S A Phone 425 454 8155 Fax 425 454 1509 URL http www icomamerica com Customer Service Phone 425 454 7619 A C N 006 092 575...

Page 51: ...6 9 16 Kamihigashi Hirano ku Osaka 547 0002 Japan A 5580I S 1999 by Icom Inc...

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