Icom IC-M2A Service Manual
  1. Manuals
  2. Brands
  3. Icom Manuals
  4. Transceiver
  5. IC-M2A
  6. Service manual
Icom IC-M2A Service Manual

Icom IC-M2A Service Manual

Vhf marine transceiver
Hide thumbs Also See for IC-M2A:
Table of Contents

Advertisement

Quick Links

See also: Instruction Manual
SERVICE
MANUAL
VHF MARINE TRANSCEIVER

Advertisement

Table of Contents
loading

Related Manuals for Icom IC-M2A

Summary of Contents for Icom IC-M2A

  • Page 1 SERVICE MANUAL VHF MARINE TRANSCEIVER...
  • Page 2 INTRODUCTION This service manual describes the latest service information for the IC-M2A/IC-M21 VHF MARINE TRANSCEIVER at the time of publication. To upgrade quality, all electrical or mechanical parts and internal circuits are subject to change without notice or oblig- ation.

  • Page 3: Table Of Contents

    TABLE OF CONTENTS SECTION SPECIFICATIONS SECTION INSIDE VIEWS SECTION DISASSEMBLY INSTRUCTIONS SECTION CIRCUIT DESCRIPTION RECEIVER CIRCUITS ........... . .4-1 TRANSMITTER CIRCUITS .
  • Page 4 SECTION 1 SPECIFICATIONS IC-M2A IC-M21 Tx: 156.025 MHz–157.425 MHz Tx: 156.000 MHz–161.450 MHz Frequencycoverage Rx: 156.025 MHz–163.275 MHz Rx: 156.000 MHz–163.425 MHz Mode 16K0G3E (FM) Power supply requirement BP-224 (7.2 V DC) Usable temperature –20 ˚C to +60 ˚C (–4˚F to +140˚F) –15 ˚C to +55 ˚C (+5˚F to +131˚F)
  • Page 5 ‘ ‘ VHF MARINE CHANNEL LIST (For IC-M2A) Channel No. Frequency (MHz) Channel No. Frequency (MHz) Channel No. Frequency (MHz) Transmit Receive Transmit Receive Transmit Receive 156.050 160.650 157.050 157.050 156.675 156.675 156.050 156.050 157.100 161.700 156.725 156.725 156.100 160.700 157.100...
  • Page 6 ‘ ‘ VHF MARINE CHANNEL LIST (For IC-M21) Channel No. Frequency (MHz) Channel No. Frequency (MHz) Channel No. Frequency (MHz) Transmit Receive Transmit Receive Transmit Receive 156.050 160.650 157.100 161.700 156.725 156.725 156.050 156.050 157.100 157.100 156.875 156.875 156.100 160.700 157.150 161.750 156.925...
  • Page 7 SECTION 2 INSIDE VIEWS • MAIN UNIT TOP VIEW BOTTOM VIEW Antenna switching circuit Antenna switching circuit (D52: 1SV307) D90: 1SV307 D91: 1SS375 (IC50: NJM2125F) Power amplifier (Q54: 2SK2974) 1st mixer (Q150: 3SK272) IF amplifier IF DETECTOR IC (Q151: 2SC2714 Y) (IC170: TA31136FN) TX/RX switch VCO circuit...

  • Page 8: Section 3 Disassembly Instructions

    SECTION 3 DISASSEMBLY INSTRUCTIONS • Removing the Rear panel • Removing the Chassis unit VR unit Rear panel Chassis unit F (Speaker connector) Rubber Front panel Front panel ¡ Unscrew 1 screw, A (2 x 10 mm), and remove 1 washer, B. ¡...

  • Page 9: Section 4 Circuit Description

    SECTION 4 CIRCUIT DESCRIPTION 4-1 RECEIVER CIRCUITS 4-1-3 2ND IF AND DEMODULATOR CIRCUITS (MAIN UNIT) 4-1-1 ANTENNA SWITCHING CIRCUIT The 2nd mixer circuit converts the 1st IF signal to a 2nd IF (MAIN UNIT) signal. A double convertion superheterodyne system (which The antenna switching circuit functions as a low-pass filter converts receive signal twice) improves the image rejection while receiving and as resonator circuit while transmitting.

  • Page 10: Transmitter Circuits

    4-1-5 SQUELCH CIRCUIT (MAIN UNIT) 4-2-3 DRIVE/POWER AMPLIFIER CIRCUITS The noise squelch circuit cuts out AF signals when no RF (MAIN UNIT) signals are received. By detecting noise components in the The signal from the VCO circuit passes through the trans- AF signals, the squelch circuit switches the AF mute switch.

  • Page 11: Pll Circuit

    4-4 POWER SUPPLY CIRCUITS 4-3 PLL CIRCUIT (RF UNIT) VOLTAGE LINES A PLL circuit provides stable oscillation of the transmit fre- 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 attached battery pack.

  • Page 12: Port Allocations

    4-5 PORT ALLOCATIONS 4-5-1 CPU (IC360) Port Port Description Description number name number name LCDC1 Input port for the [Z] key. Outputs LCD contrast control signal. DOWN LCDC2 Low : While [Z] key is pushed. BEEP Outputs beep audio signals. Input port for the [16] key.

  • Page 13: Section 5 Adjustment Procedures

    SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION EQUIPMENT GRADE AND RANGE EQUIPMENT GRADE AND RANGE Output voltage : 7.5 V DC Frequency range : 30–300 MHz DC power supply FM deviation meter Current capacity : 3 A or more Measuring range : 0 to ±10 kHz Measuring range : 0.1–10 W...
  • Page 14 • CONNECTION Standard signal generator to the antenna connector CAUTION! 0.1 V to 32 mV ( 127 dBm to 17 dBm) DO NOT transmit while an SSG is connected to the antenna connector. Attenuator to [MIC] jack Audio generator FM deviation meter 40 dB or 50 dB RF power meter to [SP] jack...
  • Page 15 5-2 PLL AND RX SENSITIVITY ADJUSTMENTS ADJUSTMENT MEASUREMENT POINT ADJUSTMENT ADJUSTMENT CONDITION VALUE UNIT LOCATION UNIT ADJUST LOCK • Operating channel : ch16 MAIN Connect a digital 1.8 V Verify VOLTAGE • Receiving multi-meter or oscil- loscope check point CP1. •...
  • Page 16 5-3 ADJUSTMENT MODE ADJUSTMENTS Select an operation using [16] key, then set specified value using [Y] / [Z] keys on the transceiver’s front panel. MEASUREMENT ADJUSTMENT ADJUSTMENT CONDITION VALUE UNIT LOCATION REFERENCE • Operating channel : ch16 Loosely couple the frequency 156.8000 MHz FREQUENCY •...

  • Page 17: Section 6 Parts List

    SECTION 6 PARTS LIST [VR UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION R500 7210003130 VARIABLE TP76N97N-13F-10KA-2497 6050011350 S.XTAL CR-726 (21.250 MHz) X170 6070000190 S.DISCRIMINATOR CDBCB450KCAY24-R0 X360 6050010290 S.XTAL CR-610 (7.9872 MHz) EP500 0910055331 PCB B 5715A 6200008070 S.COIL MLF1608E 6R8K 6.8U 6200007000 S.COIL ELJRE 82NG-F 6200003090 S.COIL...
  • Page 18 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 7030003440 S.RESISTOR ERJ3GEYJ 102 V (1 kΩ) R245 7030003440 S.RESISTOR ERJ3GEYJ 102 V (1 kΩ) ERJ1WRSJR15U (0.15 Ω) 7030007330 S.RESISTOR R250 7030003680 S.RESISTOR ERJ3GEYJ 104 V (100 kΩ) ERJ3GEYJ 471 V (470 Ω) 7030003680 S.RESISTOR ERJ3GEYJ 104 V (100 kΩ) R251...
  • Page 19 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 4030009520 S.CERAMIC C1608 CH 1H 020B-T-A C110 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A 4030009520 S.CERAMIC C1608 CH 1H 020B-T-A C115 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A [M21] only 4030008920 S.CERAMIC C1608 JB 1H 473K-T-A C120 4030006900 S.CERAMIC C1608 JB 1H 103K-T-A...
  • Page 20 [MAIN UNIT] ORDER DESCRIPTION C284 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A C285 4030011600 S.CERAMIC C1608 JB 1E 104K-T-N C286 4550006200 S.TANTALUM ECST0JY106R C287 4030007150 S.CERAMIC C1608 CH 1H 151J-T-A C288 4030008920 S.CERAMIC C1608 JB 1H 473K-T-A C289 4510005370 S.ELECTROLYTIC ECEV1AA221P C300 4030008650 S.CERAMIC C1608 JB 1H 332K-T-A...
  • Page 21 SECTION 7 MECHANICAL PARTS AND DISASSEMBLY [MAIN UNIT] [CHASSIS PARTS] REF. NO. ORDER NO. DESCRIPTION QTY. REF. NO. ORDER NO. DESCRIPTION QTY. 6910014190 2497 ANT Connector DS360 5030002220 A0153A 2510001091 036D0801A EP360 8930057100 SRCN-2497-SP-N-W MP20 8510014330 2497 VCO case 8900009640 OPC-963 MP21 8510011101 1922 VCO cover-1...
  • Page 22 MP24 (C) MP25 (C) NOTE1 MP22 (C) MP34 (C) MP14 (C) MP23 (C) NOTE1 MP37 (C) MP40 (C) MP21 (C) MP32 (C) J31 (C) MP41 (C) NOTE1 MP360 (M) MP10 (C) NOTE1 MP35 (C) MP23 (C) DS360 (M) NOTE4 VR unit MP33 (C) R500 (V) MP361 (M)
  • Page 23 • BC-150 CHARGER PARTS LIST • BC-150 VOLTAGE DIAGRAM ELECTRICAL PARTS [CHARGE UNIT] 16.4V (No load) 13.0V (Charge) REF. NO. ORDER NO. DESCRIPTION MP1(C) 7070001130 RESISTOR 120 ERG2SJ R1 120 7070001140 RESISTOR 150 ERG2SJ 7010007100 RESISTOR 1K PSD1/4V 16.4V (No load) 8.0V (Charge) 6510023070 CONNECTOR HEC2305-01-250 R2 150...
  • Page 24 SECTION 8 SEMI-CONDUCTOR INFORMATION TRANSISTOR AND FETS 2SA1588 GR 2SB1132 Q 2SC2714 Y 2SC4081 R 2SC4213 B (Symbol: ZG) (Symbol: BAQ) (Symbol: QY) (Symbol: BR) (Symbol: AB) 2SC4215 O 2SC4226 R25 2SK2973 2SK2974 3SK272 (Symbol: QO) (Symbol: R25) (Symbol: K1) (Symbol: K2974) (Symbol: K) (top view)

  • Page 25: Section 9 Board Layouts

    SECTION 9 BOARD LAYOUTS 9-1 CHARGE UNIT (BC-150) • TOP VIEW – B5787B • BOTTOM VIEW 9 - 1...

  • Page 26: Main Unit

    9-2 MAIN UNIT • TOP VIEW CP354 MC250 R236 R153 Q151 C159 C286 C158 R283 R156 C228 C285 C155 R289 R286 C283 DS242 C230 Q230 C281 C160 C284 R241 Q231 R281 R346 C231 C223 R288 CP255 C121 Q220 Q221 R220 R222 C123 L121...
  • Page 27 • BOTTOM VIEW CP355 B5714E FI170 C267 C250 R345 R253 R250 R315 R279 J240 R258 R265 R264 R303 R307 R255 C200 R272 R284 to the VR unit J240 R301 R305 R309 R311 R313 R257 R271 D350 C257 CP351 Q225 C264 R273 C170 R352...

  • Page 28: Vr Unit

    9-3 VR UNIT • TOP VIEW • BOTTOM VIEW to the MAIN unit J240 VOLIN VOLO 9 - 4...

  • Page 29: Block Diagram

    SECTION 10 BLOCK DIAGRAM BTYPE Q21, Q22: 2SC4226 R25 IC1: UPD3140GS D22, D23: HVU350B D52, D90: 1SV307 Q53: 2SK2973 Q54: 2SK2974 Q23: 2SC4215 O Q24: 2SC4215 O D50, D51: MA77 D91: 1SS375 X1: CR-726 D1: HVU17 LOOP TX/RX (21.25 MHz) BUFF PLL IC BUFF...

  • Page 30: Voltage Diagram

    SECTION 11 VOLTAGE DIAGRAM 11-1 MAIN UNIT RSSIV RSSIV RSSIV VOLIN VOLIN VOLIN C261 R207 R201 R203 BEPST BEPST BEPST 15 k 1.2 M 27 k R379 R377 R378 NOISV NOISV NOISV 82 k 82 k 82 k BEPO BEPO BEPO C202 R206...
  • Page 31 RSSIV VOLIN VCO CIRCUIT BEPST NOISV BEPO 3.6 V 473 k 47 k BEEP TEMPV MP20 VOLO 0.15 100 k 2.2 k 3216 0.001 0.001 3.3 k 3216 C191 0.01 100 k 0.047 0.001 0.001 0.001 68 k 0.001 0.001 39 k 2SC4081 R 80 nH...
  • Page 32 0.15 100 k 3216 3216 2SC4081 R 10 k 0.001 0.001 15 nH 470 P 470 P 47 P 15 k 31 nH 15 P XP6401 0.001 28 nH 28 nH 36 nH 12 nH 36 nH 1SV307 0.001 CP80 2SK2974 470 P from / to...
  • Page 33 SECTION 11 VOLTAGE DIAGRAM 11-1 MAIN UNIT RSSIV RSSIV RSSIV VOLIN VOLIN VOLIN C261 R201 R203 R207 BEPST VCO CIRCUIT 1.2 M 27 k BEPST BEPST 15 k R377 R378 R379 NOISV NOISV NOISV 82 k 82 k 82 k BEPO BEPO BEPO...

  • Page 34: Vr Unit

    11-2 VR UNIT CP506 CP505 R500 CP504 B-5715A CP503 VOLIN CP502 VOLO CP501 CP500 From BATTERY+ 11 - 2...

This manual is also suitable for:

Ic-m21

Table of Contents