Icom IC-A23 Service Manual
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Icom IC-A23 Service Manual

Air band fm transceiver
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AIR BAND FM TRANSCEIVER
iC-a23
iC-a5

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  • Page 1 AIR BAND FM TRANSCEIVER iC-a23 iC-a5...
  • Page 2 INTRODUCTION This service manual describes the latest service information for the IC-A23/IC-A5 FM TRANSCEIVER at the time of publication. MODEL VERSION SYMBOL A23-USA IC-A23 USA-1 A5-USA IC-A5 USA-1 To upgrade quality, all electrical or mechanical parts and inter- nal circuits are subject to change without notice or obligation.

  • Page 3: Table Of Contents

    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 CIRCUITS ......................4 – 2 4 – 3 PLL CIRCUIT ..........................4 – 3 4 –...
  • Page 4 • Frequency coverage : TX 118.000–136.975 MHz RX 108.000–136.975 MHz * WX 161.650–163.275 MHz * : IC-A23 only, IC-A5; 118.000–136.975 MHz : U.S.A version only • Type of emission : 6K00A3E, 16K0G3E (Weather channel; [USA] version only) • Channel spacing : 25 kHz •...
  • Page 5 Electric volume (IC505: M52429FP) RF amplifier (Q11: 3SK230) Power amplifier VOR switching (Q2: 2SK2994) (Q19: UN9210) IF amplifier [IC-A23] only YGR amplifier (Q13, Q15, Q16, (Q3: 2SK2973) Q17: 2SC4215) 1st mixer IF discreminator 2nd mixer, (Q12: 3SK151 crystal IF amplifier, 30.05 MHz)
  • Page 6 SECTION 3 DISASSEMBLY INSTRUCTIONS REMOVING THE CHASSIS PANEL REMOVING THE SHIELD PLATE q Remove 1 knob, q Unsolder 3 points, , and unscrew 1 nut, , to separate the shield plate w Unscrew 2 screws 10 mm, black). and RF unit. e Remove the chassis panel in the direction of the arrow.

  • Page 7: Circuit Description

    SECTION 4 CIRCUIT DESCRIPTION 4-1 RECEIVER CIRCUITS The 1st IF signal is applied to a crystal filter (FI1) to sup- press out-of-band signals. The filtered 1st IF signal is 4-1-1 ANTENNA SWITCHING CIRCUIT (RF UNIT) applied to the 1st IF amplifier (Q13), then applied to the 2nd The antenna switching circuit functions as a low-pass filter mixer circuit (IC1, pin 16).
  • Page 8 4-1-5 AF CIRCUIT (RF UNIT) 4-1-7 AGC CIRCUIT (RF UNIT) The AF amplifier circuit amplifies the demodulated AF sig- The AGC (Automatic Gain Control) circuit reduce signal fad- nals to drive a speaker. ing and keeps the audio output level constant. AF signals from the AM detector (Q18;...
  • Page 9 Q13 cannot be turned ON, then IC1 (pin 2) receives “HIGH” to indicate “OFF FLAG” indicator. 4-1-9 VOR NAVIGATION CIRCUIT (LOGIC UNIT) (IC-A23 ONLY) From the AF signal, the VOR circuit detects a variable signal (VORC) and reference signal (VORS) from a VOR station.

  • Page 10: Transmitter Circuits

    4-2 TRANSMITTER CIRCUITS The modulated RF signal from the buffer amplifier (Q6) is applied to the pre-drive amplifier (Q4) after being passed 4-2-1 MICROPHONE AMPLIFIER CIRCUIT through the ALC attenuator (D4). The signal is amplified at (LOGIC AND RF UNITS) the YGR (Q3) and power amplifier (Q2) to obtain 5 W of RF The microphone amplifier circuit amplifies audio signals with power (at 9.6 V DC).

  • Page 11: Pll Circuit

    4-3 PLL CIRCUIT (RF UNIT) 4-4 POWER SUPPLY CIRCUITS A PLL circuit provides stable oscillation of the transmit fre- VOLTAGE LINE quency and receive 1st LO frequency. The PLL output com- LINE DESCRIPTION pares the phase of the divided VCO frequency to the refer- The voltage from the external power supply.

  • Page 12: Port Allocations

    4-5 PORT ALLOCATIONS 4-5-2 SHIFT RESISTOR (RF UNIT; IC5) 4-5-1 CPU (LOGIC UNIT; IC1) Port Port Description Description number name number name Input port for the battely voltage Outputs detector mute signal to the DETMITE AM/FM select switch (IC2, pin 2). detection.

  • Page 13: Adjustment Procedures

    SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION Most of adjustments must be adjusted on the adjustment mode after programmed adjustment frequency data into the transceiv- er’s memory channel. When program adjustment frequency data into memory channels, the optional CS-A23 CLONING SOFTWARE (Rev.
  • Page 14 • CS-A23 SCREEN DISPLAY EXAMPLE When entering adjustment mode, Click the ’View’ ’Common Setting’ check the ’Adjust Mode Enable’ check box. on the menu bar. Untitled CS-A23 ADJUSTMENT FREQUENCY LIST File Edit View COM Port Clone Help Common Setting CHANNEL FREQUENCY (MHz) Toolbar 136.975...

  • Page 15: Pll And Transmitter Adjustments

    5-2 PLL AND TRANSMITTER ADJUSTMENTS • The “PLL LOCK VOLTAGE” adjustment must be performed at the “NORMAL” mode. • “REFERENCE FREQUENCY”, “IDLING CURRENT”, “OUTPUT POWER” AND ‘AM MODULATION” adjustments must be per- formed at the “ADJUSTMENT” mode. MEASUREMENT ADJUSTMENT ADJUSTMENT ADJUSTMENT CONDITIONS VALUE UNIT...

  • Page 16: Receiver Adjustment

    NOTE: Tune the SSG’s frequency to adjustment frequencies. VOR PHASE • Operating channel : 11 ch [VORADJ] (113.000 MHz) [DIAL] (IC-A23 only) • Connect a standard signal generator to the antenna connector and set as: panel Frequency : 113.000 MHz Level : 0.22 mV* (–60 dBm)

  • Page 17: Parts List

    SECTION 6 PARTS LIST [LOGIC UNIT] [LOGIC UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 1140009230 S.IC M38267M8L-266GP 7030003720 S.RESISTOR ERJ3GEYJ 224 V (220 kΩ) 1110004750 S.IC S-80945ALMP-DA9-T2 7030003680 S.RESISTOR ERJ3GEYJ 104 V (100 kΩ) ERJ3GEYJ 181 V (180 Ω) 1180000800 S.IC S-81350HG-KD-T1 7030003350 S.RESISTOR ERJ3GEYJ 181 V (180 Ω) 1130009680 S.IC...
  • Page 18 [LOGIC UNIT] [LOGIC UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 7030003520 S.RESISTOR ERJ3GEYJ 472 V (4.7 kΩ) 4030008920 S.CERAMIC C1608 JB 1C 473K-T-A [A23] only 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A 7030003590 S.RESISTOR ERJ3GEYJ 183 V (18 kΩ) 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A [A23] only 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A...

  • Page 19: Rf Unit

    [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 1110003490 S.IC TA31136FN (D,EL) 6200008280 S.COIL 0.30-1.7-7TL 50N 1130006220 S.IC TC4W53FU (TE12L) 6200008300 S.COIL 0.35-1.6-9TL 65N 1130008830 S.IC TB31207AFN (EL) 6200008300 S.COIL 0.35-1.6-9TL 65N 1110003690 S.IC M62354GP 75EC 6200001520 S.COIL MLF2012D R82K-T 1130007570 S.IC BU4094BCFV-E2 6200008260 S.COIL...
  • Page 20 [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION ERJ3GEYJ 221 V (220 Ω) 7030003720 S.RESISTOR ERJ3GEYJ 224 V (220 kΩ) R128 7030003360 S.RESISTOR 7030003700 S.RESISTOR ERJ3GEYJ 154 V (150 kΩ) R129 7030003540 S.RESISTOR ERJ3GEYJ 682 V (6.8 kΩ) 7030003640 S.RESISTOR ERJ3GEYJ 473 V (47 kΩ) R130 7030003480 S.RESISTOR...
  • Page 21 [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A C140 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A C141 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A C142 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A...
  • Page 22 [RF UNIT] ORDER DESCRIPTION C597 4030006900 S.CERAMIC C1608 JB 1E 103K-T-A C598 4030006850 S.CERAMIC C1608 JB 1H 471K-T-A C599 4030006850 S.CERAMIC C1608 JB 1H 471K-T-A 6450000870 CONNECTOR HEC2711-01-020 6450002150 CONNECTOR HSJ1594-010010 6510019870 S.CONNECTOR AXK5S40045P 6510021900 S.CONNECTOR BM02B-ASRS-TF 2230001070 S.SWITCH JPM1990-2711R 2230001070 S.SWITCH JPM1990-2711R 7030003860 S.JUMPER...

  • Page 23: Logic Unit

    8510013200 2378 VCO case 8510013190 2378 VCO cover 2510000840 Speaker CS028014-12 8930053580 2378 RF sheet 8510013340 2378 RF shield 8210016991 1903 front panel(C)-1 assembly [IC-A23] 8510013350 2378 VCO shield 8210017131 1903 front panel(C)-1 assembly [IC-A5] 8510013450 2378 shield plate 8010017151 1903 chassis-1...
  • Page 24 MP22 (C) MP3 (C) MP17 (C) MP16 (C) J1 (C) MP21 (C) MP8 (R) MP6 (R) MP5 (R) S1 (C) MP3 (L) MP21 (C) MP20 (C) MP19 (C) MP5 (C) DS1 (L) MP1 (L) G I C MP2 (L) MP2 (C) MC1 (L) MP28 (C) MP9 (C)
  • Page 25 SECTION SECTION 8 PARTS LIST SEMI-CONDUCTOR INFORMATION 8 - 1 TRANSISTORS NAME SYMBOL INSIDE VIEW NAME SYMBOL INSIDE VIEW NAME SYMBOL INSIDE VIEW NAME SYMBOL INSIDE VIEW MA111 MA2S111 3SK151-Y 2SB1132 R XP1501-AB MA2S728 3SK230-U1B RB060L-40 MA304 2SB1182 TL Q B1182 DTB123EK T147 XP4315...
  • Page 26 SECTION 9 BOARD LAYOUTS 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. BANK DOWN MICROPHONE 9 - 1...
  • Page 27 The combination of this page and the previous page • BOTTOM VIEW shows the unit layout in the same configuration as the actual P.C. Board. CHASSIS CHANNEL DOWN to RF unit J3 9 - 2...
  • Page 28 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. — DC IN 9 12 V ANTENNA EXT SP/MIC Battery BP-200L 9—9.6 V LIGHT...
  • Page 29 • 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. EXT SP/MIC Battery BP—200L 9—9.6 V 9 - 4...

  • Page 30: Rf Unit

    SECTION 10 BOARD LAYOUTS 2nd IF AMP (450 kHz) Q15: FI2: Q18: Q17: Q16: RF UNIT 2SC4215 2SC4215 2SC4215 CFWC450E 2SC4211 CERAMIC CHASSIS UNIT Q14: 2SD1819A 1st MIX FI1: D14, D15, D16: D1: MA77 IC1: TA31136FN D13: Q11: MA304 D8, D9: MA77 FL-325 Q12: MA304...
  • Page 31 LNJ310M6URA MA2S111 100k C4 0.1 C138 100k 0.015 100k XP1201 0.001 XP1201 C5 0.001 C128 0.1 Q12 UN9211 C129 0.1 IC-A23 only C130 0.1 CHASSIS C131 0.1 R107 LIGHTC IC8 BU4094BCFV BDET LIGHTC BUSYLED EM-140 RECC R108 PLAYC R101 100k...
  • Page 32 C100 0.001 0.015 100k R109 ANA IN 0.001 0.001 100k 100k 100k ANA OUT PLAYL PLAYE Q12 UN9211 OUT2 RECLED IC-A23 only XCLK VCCD C127 0.001 0.47 OUT1 MA8036L IC8 BU4094BCFV IC9 BA3308F LIGHTC RECC RECC PLAYC PLAYC VORON VORON...
  • Page 33 0.001 100k 0.001 XP1201 100k 100k ANA OUT C5 0.001 PLAYL C128 0.1 PLAYE Q12 UN9211 OUT2 RECLED C129 0.1 IC-A23 only XCLK C130 0.1 CHASSIS VCCD C131 0.1 C127 R107 LIGHTC 0.001 0.47 IC8 BU4094BCFV OUT1 MA8036L IC9 BA3308F...
  • Page 34 11 - 2 RF UNIT RX: 0.0V TX: 3.2V 0.001 EXCCL3225U RX: 0.0V 9.3V RX: 0.0V TX: 3.5V 2SB1132 TX: 4.9V 0.001 0.001 36nH 2SC4211 0.001 0.001 0.001 0.001 80nH 39nH 1SV246 2.2k 0.001 C402 0.001 0.1 H 1SV246 0.001 0.001 MA77 68nH...
  • Page 35 RX: 0.0V TX: 1.8V 100k EXCCL3225U 100k 0.001 36nH 0.001 0.001 0.001 0.001 39nH 0.001 0.82 H UMS1 0.001 ANTENNA 68nH 0.001 0.001 0.001 65nH 65nH 50nH 27nH 19.5nH 60nH 2SK2973 MA77 2SK2974 CHASSIS UNIT MA728 0.001 0.5p MA728 50nH 0.001 54nH MA77...
  • Page 36 11 - 2 RF UNIT RX: 0.0V RX: 0.0V TX: 1.8V TX: 3.2V 0.001 100k EXCCL3225U RX: 0.0V 9.3V RX: 0.0V TX: 3.5V 2SB1132 TX: 4.9V 0.001 100k 0.001 0.001 36nH 2SC4211 0.001 0.001 0.001 0.001 0.001 2.2k 80nH 39nH 1SV246 0.001 0.82 H...
  • Page 37 6-9-16, Kamihigashi, Hirano-ku, Osaka 547-0002, Japan Phone : 06 6793 5302 : 06 6793 0013 : http://www.icom.co.jp/world/index.html < > Corporate Headquarters Communication Equipment 2380 116th Avenue N.E., Bellevue, WA 98004, U.S.A. Himmelgeister Str. 100, D-40225 D sseldorf, Germany Phone : ( 425 ) 454-8155...
  • Page 38 Count on us! 13706MZ-CD 6-9-16, Kamihigashi, Hirano-ku, Osaka 547-0002, Japan ' 2000 Icom Inc.

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