Icom IC-A23 Service Manual Download Page 5

Page: 5 / 38

Clock oscillator
(X1: CR-534,
5.039 MHz)

EEPROM
(IC7: HN58X2432)

RESET
(IC2: S-80945ALMP)

PTT detector
(Q10: 2SB1462)

Microphone
mute
(Q12: UN9211)

CPU
(IC1: M38267M6L)

VOR circuit
(IC-A23 only)

Microphone
amplifier
(IC9: BA3308F)

AF amplifier
(IC6: TA7368F)

YGR amplifier
(Q3: 2SK2973)

VCO circuit

Reference
oscillator
(X2: CR-683,
29.600 MHz)

Power amplifier
(Q2: 2SK2994)

RF amplifier
(Q11: 3SK230)

ALC detector
(D2, D3: MA728)

Antenna switching
circuit

AF amplifier/
Low-pass filter
(IC510: TC75W51F)

ALC CTRL
(Q1: UMS1)

VOR switching

(Q19: UN9210)

[IC-A23] only

1st mixer
(Q12: 3SK151
30.05 MHz)

ALC amplifier
(Q5: 2SC4211)

Lo switching diode
(D6, D17: MA77)

Electric volume
(IC505: M52429FP)

IF amplifier
(Q13, Q15, Q16,
Q17: 2SC4215)

2nd mixer,
IF amplifier,
Noise detector
(IC1: TA31136FN)

PLL IC
(IC3: TB31207FN)

Q16

Q15

Q13

IF discreminator
crystal
(X1: CDBCA450CX24
450 kHz)

2 - 1

SECTION 2

INSIDE VIEWS

• LOGIC UNIT

• RF UNIT

BOTTOM VIEW

TOP VIEW

*IC-A5/A23-chg 00.8.23 4:23 PM Page 2 - 1

Summary of Contents for IC-A23

Page 1: ...iC a5 AIR BAND FM TRANSCEIVER iC a23 iC a23 iC a5 ...

Page 2: ...H BT 2 10 ZK IC A5 CHASSIS 6 pieces Addresses are provided on the inside back cover for your convenience 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 par...

Page 3: ...CPU PORT ALLOCATIONS 4 5 SECTION 5 ADJUSTMENT PROCEDURES 5 1 PREPARATION 5 1 5 2 PLL ADJUSTMENT 5 2 5 3 TRIMMER ADJUSTMENT 5 3 5 4 RECEIVER ADJUSTMENT 5 7 SECTION 6 PARTS LIST SECTION 7 MECHANICAL PARTS AND DISASSEMBLY SECTION 8 SEMI CONDUCTOR INFORMATION SECTION 9 BOARD LAYOUTS 9 1 LOGIC UNIT 9 1 9 2 RF UNIT 9 3 SECTION 10 BLOCK DIAGRAM SECTION 11 VOLTAGE DIAGRAM 11 1 LOGIC UNIT 11 1 11 2 RF UNIT...

Page 4: ...put power at 9 6 V DC 5 0 W PEP typical 1 5 W CW typical with supplied battery pack Modulation system Low level modulation Modulation limiting 70 100 of max deviation Audio harmonic distortion Less than 10 at 60 modulation Hum and noise ratio More than 35 dB Spurious emissions More than 60 dB Microphone impedance MIC 150 Ω RECEIVER Receive system Double conversion superheterodyne system Intermedia...

Page 5: ...RF amplifier Q11 3SK230 ALC detector D2 D3 MA728 Antenna switching circuit AF amplifier Low pass filter IC510 TC75W51F ALC CTRL Q1 UMS1 VOR switching Q19 UN9210 IC A23 only 1st mixer Q12 3SK151 30 05 MHz ALC amplifier Q5 2SC4211 Lo switching diode D6 D17 MA77 Electric volume IC505 M52429FP IF amplifier Q13 Q15 Q16 Q17 2SC4215 2nd mixer IF amplifier Noise detector IC1 TA31136FN PLL IC IC3 TB31207FN...

Page 6: ... r Unplug J1 to separate LOGIC unit and RF unit t Remove the LOGIC unit in the direction of the arrow 3 REMOVING THE SHIELD PLATE q Unsolder 3 points F to separate the shield plate and RF unit w Unscrew 1 screw G 2 4 mm silver 4 REMOVING THE RF UNIT q Unsolder 1 point H to separate the ANT plug w Unscrew 5 screws I 2 4 mm silver to separate the RF unit e Remove the RF unit in the direction of the ...

Page 7: ...uit to pro duce a 30 05 MHz 1st IF signal The 1st IF signal is applied to a crystal filter FI1 to sup press out of band signals The filtered 1st IF signal is applied to the 1st IF amplifier Q13 then applied to the 2nd mixer circuit IC1 pin 16 4 1 4 2ND IF AND DEMODULATOR CIRCUITS RF UNIT The 2nd mixer circuit converts the 1st IF signal into a 2nd IF signal A double conversion superheterodyne syste...

Page 8: ...nalyzes the noise condition and outputs the con trol signal to the shift resistor IC5 The shift resistor IC5 pin 14 outputs the squelch control signal via AFC line The signal is applied to the AF out control circuit Q36 Q35 to control the power amplifier IC6 and cut the AF signal line 4 1 7 AGC CIRCUIT RF UNIT The AGC Automatic Gain Control circuit reduce signal fad ing and keeps the audio output ...

Page 9: ...t passes through the 30 Hz bandpass filter IC12 R83 R85 R88 C112 C113 and is converted to a square wave signal at the VORC comparator IC14 The square wave signal is then applied to the CPU IC1 pin 22 as variable signal VORC The 9960 Hz component passes through the 10 kHz band pass filter IC12 R79 R81 C108 C109 These compo nents are FM modulated with 480 Hz deviation and 30 Hz modulation Signals ar...

Page 10: ...es this to obtain a specified transmit output power The modulated RF signal from the buffer amplifier Q6 is applied to the pre drive amplifier Q4 after being passed through the ALC attenuator D4 The signal is amplified at the YGR Q3 and power amplifier Q2 to obtain 5 W of RF power at 9 6 V DC The amplified signal passes through the low pass filter L5 C11 C16 The filtered signal is applied to the a...

Page 11: ...e receive 1st mixer Q12 or transmit buffer amplifier circuit Q6 via the T R switching diode D6 D17 4 4 POWER SUPPLY CIRCUITS VOLTAGE LINE Cont 16 17 PLL Loop filter OSC Tr VCO Buffer Buffer Buffer Q27 Buffer Q28 Q29 Q30 R134 R135 C168 C169 3 4 5 PCK IC3 PLL IC PDATA PSTB to 1st mixer circuit D17 D6 9 12 13 14 11 8 Q31 Q32 D24 C198 C177 From IC4 pin 14 C175 2ndLO signal to the IF IC IC1 pin 2 X2 R1...

Page 12: ...5 Port name VIN VORD RSSI RFDETV THRMC SBATT PDATA PCK PSTB BEEP VORS DICK DIUD LIGHT BPCPI CLOUT CLIN VORC POWER PTT JACKDET DCC RESET EDATA UNLK PCON ECK Description Input port for the battely voltage detection Input port for the VOR signal detec tion Input port for the receive signal level Input port for the power detection of power amplifier RF unit Q2 Input port for the transceiver s internal...

Page 13: ... key For example D setup t Follow the prompts y Program group CS A23 appears in the Programs fold er of the Start menu ADJUSTMENT FREQUENCY DATA When program the adjustment frequency data into memory channel back up the original memory data using the cloning software and OPC 478 and then reprogram it after adjust ment CAUTION When program the adjustment frequency data into the transceiver the tran...

Page 14: ... bar to the antenna connector RF power meter 0 1 10 W 50 Frequency counter Attenuator 40 dB or 50 dB Modulation analyzer Standard signal generator 0 1 V to 32 mV 127 dBm to 17 dBm CAUTION Audio generator AC millivolt meter Distortion meter Speaker 8 to the MIC SP jack to the MIC SP jack OPC 478 to an RS 232C port Personal computer DB9 female plug incl level converter circuit CAUTION DC ammeter DC ...

Page 15: ...ter or a 50 Ω dummy load to the antenna connector Transmitting Operating channel 2 ch PWRADJ 136 975 MHz Transmitting Operating channel 2 ch PWRADJ 136 975 MHz Connect an audio generator to the MIC connector and set as 1 kHz 200 mV Set a modulation analyzer as HPF OFF LPF OFF De emphasis OFF Detector P P 2 Transmitting Connect an audio generator to MIC connector and set as 1 kHz 20 mV Transmitting...

Page 16: ... Connect a standard signal generator to the antenna connector and set as Frequency 118 200 MHz Level 0 5 µV 113 dBm Modulation OFF Receiving Same adjustment as step 1 for following channels 8 ch ASADJT 136 975 MHz 9 ch FSADJS 161 650 MHz 10 ch FSADJT 161 650 MHz NOTE Tune the SSG s frequency to adjustment frequencies Operating channel 11 ch VORADJ 113 000 MHz Connect a standard signal generator to...

Page 17: ... V 10 kΩ R21 7030003560 S RESISTOR ERJ3GEYJ 103 V 10 kΩ R22 7030003520 S RESISTOR ERJ3GEYJ 472 V 4 7 kΩ R23 7030003720 S RESISTOR ERJ3GEYJ 224 V 220 kΩ R24 7030003680 S RESISTOR ERJ3GEYJ 104 V 100 kΩ R25 7030003350 S RESISTOR ERJ3GEYJ 181 V 180 Ω R26 7030003350 S RESISTOR ERJ3GEYJ 181 V 180 Ω R27 7030003440 S RESISTOR ERJ3GEYJ 102 V 1 kΩ R28 7030003400 S RESISTOR ERJ3GEYJ 471 V 470 Ω R30 703000360...

Page 18: ...103K T A C49 4550005980 S TANTALUM TEMSVA 1A 475M 8L C50 4030008920 S CERAMIC C1608 JB 1C 473K T A C51 4030006860 S CERAMIC C1608 JB 1H 102K T A C52 4030006860 S CERAMIC C1608 JB 1H 102K T A C53 4030006860 S CERAMIC C1608 JB 1H 102K T A C59 4030006860 S CERAMIC C1608 JB 1H 102K T A C65 4030006860 S CERAMIC C1608 JB 1H 102K T A C66 4030006860 S CERAMIC C1608 JB 1H 102K T A C86 4030008860 S CERAMIC ...

Page 19: ...1 5TR 19 5N L7 6200008400 S COIL 0 35 1 6 6TL 36N L8 6200005710 S COIL ELJRE 27NG F L9 6200003590 S COIL EXCCL3225U1 L10 6200002370 S COIL LQN 1A 39NJ04 L11 6200006670 S COIL ELJRE 68NG F L12 6200008190 S COIL 0 25 1 9 8TL 80N L13 6200001630 S COIL ELJNC R10K F L14 6200002190 S COIL MLF2012A 4R7K T L15 6200008170 S COIL 0 35 1 6 8TL 54N L16 6200008280 S COIL 0 30 1 7 7TL 50N L18 6200007750 S COIL ...

Page 20: ... V 68 kΩ R125 7030003320 S RESISTOR ERJ3GEYJ 101 V 100 Ω R126 7030003360 S RESISTOR ERJ3GEYJ 221 V 220 Ω R127 7030003540 S RESISTOR ERJ3GEYJ 682 V 6 8 kΩ R128 7030003360 S RESISTOR ERJ3GEYJ 221 V 220 Ω R129 7030003540 S RESISTOR ERJ3GEYJ 682 V 6 8 kΩ R130 7030003480 S RESISTOR ERJ3GEYJ 222 V 2 2 kΩ R131 7030003560 S RESISTOR ERJ3GEYJ 103 V 10 kΩ R133 7030003600 S RESISTOR ERJ3GEYJ 223 V 22 kΩ R134...

Page 21: ...30006900 S CERAMIC C1608 JB 1E 103K T A C130 4510006220 S ELECTROLYTIC ECEV1CA101UP C140 4030006860 S CERAMIC C1608 JB 1H 102K T A C141 4030006860 S CERAMIC C1608 JB 1H 102K T A C142 4030006860 S CERAMIC C1608 JB 1H 102K T A C143 4030006860 S CERAMIC C1608 JB 1H 102K T A C144 4030006860 S CERAMIC C1608 JB 1H 102K T A C145 4030006860 S CERAMIC C1608 JB 1H 102K T A C146 4030006860 S CERAMIC C1608 JB...

Page 22: ...010 J3 6510019870 S CONNECTOR AXK5S40045P J4 6510021900 S CONNECTOR BM02B ASRS TF S1 2230001070 S SWITCH JPM1990 2711R S2 2230001070 S SWITCH JPM1990 2711R W12 7030003860 S JUMPER ERJ3GE JPW V W14 7030003860 S JUMPER ERJ3GE JPW V W15 7030000010 S JUMPER MCR10EZHJ JPW 000 W16 7030003860 S JUMPER ERJ3GE JPW V W17 7030003860 S JUMPER ERJ3GE JPW V EP1 6910012350 S BEAD MMZ1608Y 102BT EP2 0910052893 PC...

Page 23: ...duct Battery BP 200L ACC A5 USA A23 USA only 1 EP3 Optional product Chager BC 110A A5 USA A23 USA only 1 MP1 8930044450 1903 belt clip 1 MP2 8010011960 Strap belt HK 005 1 W1 8900009980 Cable OPC 967 ACC A23 USA only 1 ZP1 0800005690 Lazer case LC 147 ACC A23 USA only 1 7 1 Screw abbreviations PH Pan head FH Flat head NI Nickel ZK Black SECTION 7 MECHANICAL PARTS AND DISASSEMBLY 7 1 CABINET PARTS ...

Page 24: ...MP2 C MP6 C MP21 C MP21 C MP5 L MP4 L MP3 R MP7 R MP4 R MP9 R MP8 R MP6 R MP5 R J1 C MP2 L MP20 C MP16 C MP17 C MP28 C MP21 C MP11 C MP27 C MP4 C W1 C MP13 C MP14 C SP1 C MP1 C MP25 C MP21 C LOGIC UNIT RF UNIT Note C CHASSIS PARTS R RF UNIT L LOGIC UNIT IC A5 A23 chg 00 8 23 4 33 PM Page 7 2 ...

Page 25: ...H 3SK230 U1B U1B 2SK2974 K2974 DTB123EK T147 F12 DTC144EE TL 24 HAT1024R EL 1024 UMS1 TL S1 UN9115 6E UN9210 8L UN9211 8A UN9213 8C C1 C2 E B1 B2 XP1201 AI 2SC3357 RF RF 2SC4116 BL LL 2SC4211 6 TL L6 2SC4215 O QO 2SC4226 R25 R25 2SC4403 3 TL LY3 2SD1819A R LG 2SD2216 S Y 8 1 8 2 DIODES NAME SYMBOL INSIDE VIEW A C HVU17TRF E A C MA304 7R A C MA8024 2 4 MA8036 L 3_6 MA8051 H 5 1 MA8100 10 A C MA111 ...

Page 26: ... MR DOWN UP PWR SQL ANL BANK F 9 1 9 1 LOGIC UNIT TOP VIEW The combination of this page and the next page shows the unit layout in the same configuration as the actual P C Board SECTION 9 BOARD LAYOUTS IC A5 A23 chg 00 8 23 5 31 PM Page 9 1 ...

Page 27: ...ORON RSSI JACKDET VOLCK RFSTB SCK VOLDATA GND GND PTT EXTPTT LIGHT DASTB GND GND GND VREC GND BEEP MOD GND GND to RF unit J3 UP E DOWN CHANNEL CHASSIS S1 BOTTOM VIEW The combination of this page and the previous page shows the unit layout in the same configuration as the actual P C Board IC A5 A23 chg 00 8 23 5 29 PM Page 9 3 ...

Page 28: ...JACKDET VOLCK RFSTB SCK VOLDATA GND GND PTT EXTPTT LIGHT DASTB GND GND GND VREC GND BEEP MOD GND GND to RF unit J3 J1 DC IN 9 12 V CHG 1 2 P1 SP1 3 1 2 PTT LIGHT 1 2 3 MP1 2 7 6 1 4 5 9 2 RF UNIT TOP VIEW The combination of this page and the next page shows the unit layout in the same configuration as the actual P C Board IC A5 A23 chg 00 8 23 5 31 PM Page 9 5 ...

Page 29: ... 1 2 3 MP1 Battery BP 200L 9 9 6 V EXT SP MIC J2 BOTTOM VIEW The combination of this page and the previous page shows the unit layout in the same configuration as the actual P C Board IC A5 A23 chg 00 8 23 5 35 PM Page 9 7 ...

Page 30: ...32 Q2 2SC4116 LED DRV Q8 XP1201 LED DRV Q9 XP1201 LED DRV DS4 LT1EP53A Q7 2SB1132 Q8 2SC4211 TX CTRL D7 MA111 S5 POWER SW D4 DA112 D3 DAP202U INITIAL SET Q10 2SB1462 D14 MA2S111 PTT DET IC9 BA3308F MIC ANL AMP R41 IC8 BU4094BCFV SHIFT RESISTOR Q19 UN9210 VOR SW CMP BUFF AMP BPF BPF IC15 ISD1420SI VOICE REC PLAY Q11 XP4315 ALC CTRL Q15 XP4315 VOR CTRL Q25 2SB1132 Q26 UN9211 D23 MA133 D27 MA111 EXT ...

Page 31: ...NLK CHGC COM0 COM1 COM2 COM3 R2 100k R3 100k R4 100k C138 0 1 C139 0 1 C140 10 R1 47k C2 0 1 P76 P75 P74 P73 P72 P71 P70 INT0 RESET XCIN XCOUT XIN XOUT VSS P27 P26 P25 P24 P23 P22 P21 P20 P17 P16 P15 SEG39 P14 SEG38 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 SEG38 SEG39 EDATA VOLCK SDATA DASTB VOLDATA SCK RFSTB UNLK UNLK KR0 KR1 KR2 KR3 MASTB RESET RESET DCC DCC KR4...

Page 32: ...111 3 3 C103 10 R74 220k R73 4 7k R75 56k R76 33k R79 6 8k C105 10 R81 1 8k C108 0 001 R80 150k C109 0 001 C106 0 001 R77 220k 0 R84 4 7k C113 0 1 R87 TBPS1S333K460H5Q R85 18k C112 0 1 R83 220k R78 4 7k R91 39k R88 33k R82 4 7k 1 2 3 4 5 6 7 8 9 10 11 12 13 14 R64 4 7k R63 15k R62 220k R61 47k C102 470p C115 0 1 C114 0 1 R66 220k 1 2 3 4 5 6 7 8 IC13 NJM2904V C125 10 R68 270k R67 10k C119 0 001 R8...

Page 33: ...8 22 R22 4 7k R20 10k IC16 S 81250SG QD Q6 UN9213 R98 1M 4 5 1 2 3 4 5 OUT VDD VSS CD NC C25 0 01 C26 47 R18 10k C22 0 001 R17 10k Q3 2SD2216 C20 0 001 C6 0 001 R16 100k R5 100k UNLK CHGC COM0 COM1 COM2 COM3 R2 100k R3 100k R4 100k C138 0 1 C139 0 1 C140 10 R1 47k C2 0 1 P76 P75 P74 P73 P72 P71 P70 INT0 RESET XCIN XCOUT XIN XOUT VSS P27 P26 P25 P24 P23 P22 P21 P20 P17 P16 P15 SEG39 P14 SEG38 26 27...

Page 34: ... EXTPTT EXTMIC STDET R160 47k 3 1 4 R162 100k C540 4 7 R163 100k R161 270k IC14 NJM2107F 5 2 R556 47k R550 100k C597 0 01 R158 22k WXC WXC EMBI AFC EMBI AFC SBATT VCC MOD BEEP 5V CHGC HV EMBI SBATT VCC CHGC HV UNLK VOLDATA JACKDET VOLCK EXTMIC EXTPTT VREC R159 100k R549 120k R28 100 C41 0 001 R29 15k R30 220 R31 33k R32 100 C37 10 R26 100k C38 0 001 C39 0 001 R25 1k R27 1k C40 8p R24 10k R23 10k R...

Page 35: ...C126 0 01 C195 100 R139 10 C181 0 1 C182 22p R140 180 C183 4 7 C196 0 001 C184 100 C185 4 7 R147 12k R145 10k R141 10k R146 10k R148 1k C340 100 R110 1k C140 0 001 R109 10k EXTSP EXTPTT EXTPTT EXTMIC STDET EXTMIC STDET C565 0 001 C567 0 001 C572 12p R107 150 R108 18 C130 100 C142 0 001 C143 0 001 C144 0 001 C145 0 001 C146 0 001 C141 0 001 SPE MICE R55 270k R56 TBPS1R154K475H5Q C58 7p C76 5p C75 3...

Page 36: ...7 0 001 C572 12p R107 150 R108 18 C130 100 C142 0 001 C143 0 001 C144 0 001 C145 0 001 C146 0 001 C141 0 001 SPE MICE R55 270k R56 TBPS1R154K475H5Q C58 7p C76 5p C75 33p R112 150 C171 0 001 R113 27k R111 10k C129 0 01 R106 100k R160 47k 3 1 4 R162 100k C540 4 7 R163 100k R161 270k IC14 NJM2107F 5 2 R556 47k R550 100k C597 0 01 R158 22k WXC WXC EMBI AFC EMBI AFC SBATT VCC VCC MOD BEEP 5V CHGC CHGC ...

Page 37: ...L http www icom france com Crta de Gracia a Manresa Km 14 750 08190 Sant Cugat del Valles Barcelona SPAIN Phone 93 590 26 70 Fax 93 589 04 46 URL http www icomspain 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 Glenwood Centre 150 6165 Highway 17 Delta B C V4K 5B8 Canada ...

Page 38: ...Count on us iC a23 iC a5 ...

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