Icom IC-M402 Service Manual
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Icom IC-M402 Service Manual

Vhf marine transceiver
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SERVICE
MANUAL
VHF MARINE TRANSCEIVER

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  • Page 1 SERVICE MANUAL VHF MARINE TRANSCEIVER...
  • Page 2 This service manual describes the latest service information NEVER connect the transceiver to an AC outlet or to a DC for the IC-M402 VHF MARINE TRANSCEIVER at the time of power supply that uses more than 16 V. This will ruin the publication.

  • Page 3: Table Of Contents

    IC-M402 ........

  • Page 4: Section 1 Specifications

    SECTION 1 SPECIFICATIONS ‘ ‘ GENERAL • Frequency coverage : 156.025–157.425 MHz (Tx) 156.050–163.275 MHz (Rx) • Mode : 16K0G3E (FM) 16K0G2B (DSC) • Usable channels : All USA, international and Canadian channels plus 10 weather channels • Power supply requirement : 13.8 V DC ±10 % (negative ground) •...
  • Page 5 ‘ ‘ VHF MARINE CHANNEL LIST Channel No. Frequency (MHz) Channel No. Frequency (MHz) Channel No. Frequency (MHz) Transmit Receive Transmit Receive Transmit Receive 156.050 160.650 157.050 157.050 156.675 156.675 156.050 156.050 157.100 161.700 156.725 156.725 156.100 160.700 157.100 157.100 156.875 156.875 156.150...

  • Page 6: Section 2 Inside Views

    SECTION 2 INSIDE VIEWS 2-1 IC-M402 • MAIN UNIT AF power amplifier Pre-driver (IC9: LA4425A) (Q10: 2SC3775 3) Reference oscillator (X2: CR-659) YGR amplifier Antenna switching circuit (Q11: 2SC3268) VCO circuit DSC decoder (IC6: NJM2211M) 1st mixer (Q1:3SK272) FM IF IC...

  • Page 7: Hm-127 (Optional Unit)

    2-2 HM-127 (OPTIONAL UNIT) • TOP VIEW (DS1: A0119) • BOTTOM VIEW System clock (X1: CSTCC4.91MG) (IC1: µPD789405AGK-A30-9EU) Dimmer circuit Data buffer circuit Reset IC 8V regulator (IC7: S-80928ANMP) (IC6: TA7808F) 5V regulator Volume IC (IC5: TA78L05F) (IC3: M62429FP) AF/MIC switch (IC9: TC4W53FU) AF amplifier MIC amplifier...

  • Page 8: Section 3 Disassembly Instructions

    SECTION 3 DISASSEMBLY INSTRUCTIONS • • REMOVING THE CASE REMOVING THE MAIN UNIT 1 Unscrew 6 screws, A. 1 Unsolder DC cable (4 points) and antenna connector, Note: When replacing the screw, 10–12 kg of torque MUST B (2 points), as shown below. be applied to ensure water resistance.

  • Page 9: Section 4 Circuit Description

    SECTION 4 CIRCUIT DESCRIPTION 4-1 RECEIVER CIRCUITS The signals from the RF circuit are mixed with the VCO sig- nals at the 1st mixer circuit (Q1) to produce a 21.7 MHz 1st 4-1-1 ANTENNA SWITCHING CIRCUIT IF signal. (MAIN UNIT) The antenna switching circuit functions as a low-pass filter The 1st IF signal is applied to two crystal filters (FI1, FI2) to while receiving and as resonator circuit while transmitting.

  • Page 10: Transmitter Circuits

    NOAA weather radio broadcast is The power amplifier circuit amplifies the driver signal to an received, the IC-M402 emits beep tones and indicates flash- output power level. ing “ALT” on the display to inform of an emergency weather report on the air.

  • Page 11: Pll Circuits

    4-2-5 APC CIRCUIT (MAIN UNIT) The PLL circuit , using a one chip PLL IC (MAIN unit; IC2), directly generates the transmit frequency and receive 1st IF The APC circuit stabilizes transmit output power. frequency with VCOs. The PLL sets the divided ratio based on serial data from the CPU on the LOGIC unit and com- The RF output signal from the power amplifier (IC3) is pares the phases of VCO signals with the reference oscilla-...

  • Page 12: Dsc Circuits

    4-3-4 VCO CIRCUIT (MAIN UNIT) 4-6 POWER SUPPLY CIRCUITS The VCO outputs from Q4–Q6 are buffer-amplified at the buffer amplifiers (Q7 and Q9), and are then sent to the Tx/Rx LINE DESCRIPTION switch (D5 and D6). The receive LO signal is applied to the 1st mixer circuit (Q1) through a low-pass filter, and the trans- The voltage from the connected DC power sup- mit signal is applied to the pre-drive amplifier (Q10).

  • Page 13: Port Allocations

    4-7 PORT ALLOCATIONS 4-7-1 CPU (LOGIC BOARD; IC1) Port Port Description Description number name number name Outputs control signal for the LCD TXDET Input port for TX LED control signal. contrast. Input port for the smart mic functions. CONT1 CONT2 CONT1 CONTRAST 2.02 V: [UP] is pushed.

  • Page 14: Section 5 Adjustment Procedures

    SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION REQUIRED TEST EQUIPMENT EQUIPMENT GRADE AND RANGE EQUIPMENT GRADE AND RANGE Output voltage : 13.8 V DC Frequency range : 300–3000 Hz DC power supply Audio generator Current capacity : 10 A or more Measuring range : 1–500 mV Measuring range...

  • Page 15: Pll Adjustments

    5-2 PLL 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. • Operating channel : ch16 1.6 V •...

  • Page 16: Transmitter Adjustments

    5-3 TRANSMITTER ADJUSTMENTS ADJUSTMENT MEASUREMENT POINT ADJUSTMENT ADJUSTMENT CONDITION VALUE UNIT LOCATION UNIT ADJUST OUTPUT • Operating channel : ch16 Rear Connect 26 W MAIN POWER • Output power : High Panel power meter to the • Transmitting antenna connector. FREQUENCY •...
  • Page 17 Output power adjustment R138 Frequency deviation adjustment Squelch level adjustment Squelch level check point Audio generator [PTT] 300 Hz to 3 kHz AC millivoltmeter 2 200 mV 5 - 4...

  • Page 18: Section 6 Parts List

    SECTION 6 PARTS LIST 6-1 IC-M402 [LOGIC BOARD] [LOGIC BOARD] ORDER ORDER DESCRIPTION DESCRIPTION 1140009410 S.IC HD6433847RA29H (FX-2438A) 7030003560 S.RESISTOR ERJ3GEYJ 103 V (10 kΩ) 1130009680 S.IC HN58X2432TI 7030004120 S.RESISTOR ERJ3GEYJ 203 V (20 kΩ) 1130007570 S.IC BU4094BCFV-E2 7030004120 S.RESISTOR ERJ3GEYJ 203 V (20 kΩ)
  • Page 19 [LOGIC BOARD] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 0910053453 PCB B 5584C 1790000620 S.DIODE MA77 (TX) 8930054970 LCD CONTACT SRCN-2438-SP-N-W 1790000620 S.DIODE MA77 (TX) 1720000370 S.VARICAP HVU350TRF 1720000370 S.VARICAP HVU350TRF 1790000620 S.DIODE MA77 (TX) 1790000620 S.DIODE MA77 (TX) 1750000550 S.DIODE 1SS355 TE-17 1790000690 S.DIODE HSM88ASR-TR...
  • Page 20 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION ERJ3GEYJ 331 V (330 Ω) 7030003380 S.RESISTOR R112 7030003480 S.RESISTOR ERJ3GEYJ 222 V (2.2 kΩ) 7030003440 S.RESISTOR ERJ3GEYJ 102 V (1 kΩ) R113 7030003680 S.RESISTOR ERJ3GEYJ 104 V (100 kΩ) ERJ3GEYJ 100 V (10 Ω) 7030003200 S.RESISTOR R121 7030003480 S.RESISTOR...
  • Page 21 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 4510004630 S.ELECTROLYTIC ECEV1CA100SR C105 4010007630 CERAMIC HM60SJ CH 270J 500V 4030011810 S.CERAMIC C1608 JB 1A 224K-T-N C106 4010005790 CERAMIC HM60SJ YB 102K 500V 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A C107 4010005500 CERAMIC HM60SJ CH 150J 500V 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A...

  • Page 22: Front Unit

    [MAIN UNIT] [FRONT UNIT] ORDER ORDER DESCRIPTION DESCRIPTION C196 4030006900 S.CERAMIC C1608 JB 1E 103K-T-A 0800005970 MICROPHONE HM-129B ACC <KN> C197 4010007630 CERAMIC HM60SJ CH 270J 500V 0800005980 MICROPHONE HM-129W ACC <KN> C198 4010008530 CERAMIC HM74SJ CH 360J 500V C199 4030007090 S.CERAMIC C1608 CH 1H 470J-T-A C200...
  • Page 23 6-2 MH-127 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 1140009280 S.IC µPD78F9418AGK-9EU (FX-2345D) 7030003440 S.RESISTOR ERJ3GEYJ 102 V (1 kΩ) 1110001810 S.IC TA7368F (TP1) 7030003640 S.RESISTOR ERJ3GEYJ 473 V (47 kΩ) 1110004490 S.IC M62429FP 700C 7030003440 S.RESISTOR ERJ3GEYJ 102 V (1 kΩ) 1120002830 S.IC NJM2125F-TE1 7030003520 S.RESISTOR...
  • Page 24 6-3 MH-129 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION R20J 12 K Ω 5040002310 S.LED SML-311YTT86 7010006890 RESISTOR R20J 6.8K Ω 5040002310 S.LED SML-311YTT86 7010006880 RESISTOR R20J 15 K Ω 5040002310 S.LED SML-311YTT86 7010006900 RESISTOR R20J 33 K Ω DS10 5040002310 S.LED SML-311YTT86...

  • Page 25: Ic-M402

    SECTION 7 MECHANICAL PARTS AND DISASSEMBLY 7-1 IC-M402 [VR-A BOARD] [CHASSIS PARTS] REF. NO. ORDER NO. QTY. DESCRIPTION REF. NO. ORDER NO. QTY. DESCRIPTION 7210002350 TP96N97N15F-10KA-1301 (incl. nut) 6510004880 Connector MR-DSE-01 8900010470 Cable OPC-1029 (incl. nut, packing) 8900010480 Cable OPC-1040...
  • Page 26 MP17 (C) MP13 (C) MP7 (C) J1 (C) MP19 (C) MP18 (C) MP5 (C) MP11 (C) MP18 (C) MP8 (C) MP18 (C) MP14 (C) MP4 (C) W2 (C) MP18 (C) MP18 (C) MP20 (C) MP13 (C) MP19 (C) MP6 (F) W1 (C) W3 (F) MP18 (C)
  • Page 27 MP10 8930039000 1757 sheet Screw FT B0 M2 × 5 NI-ZU BiH: Bind head MP12 8820001150 2352 screw MP11 8810009180 MP13 8850001850 ICOM washer (Y) MP12 8930053750 2417 plate MP14 8930052340 O-ring (AE) MP13 8210017250 2417 rear panel [BLACK] MP15...
  • Page 28 SECTION 8 SEMI-CONDUCTOR INFORMATION • • TRANSISTOR AND FET’S DIODES 2SA1576 R 2SA1588 2SB1132 R 2SB1143 S 2SC2714 Y 1SS355 1SS375 DA204 U DAN202 U HSM88ASR (Symbol: A) (Symbol: FH) (Symbol: K) (Symbol: N) (Symbol: FR) (Symbol: ZG) (Symbol: BAR) (Symbol: B1143) (Symbol: QY) (Symbol: C3)
  • Page 29 SECTION 9 BOARD LAYOUTS 9-1 VR-A BOARD 9-3 HM-129 to Main unit J5 • TOP VIEW B-5585B 9-2 VR-B BOARD • BOTTOM VIEW to Main unit J5 B-5586B 9 - 1...
  • Page 30 9-4 LOGIC BOARD • TOP VIEW B5584B ICOM SP— to Front unit SP1 to Front unit SP1 From Smart Mic HM-129 From/to Remoto Mic HM-127 From External GPS From/to Main unit J6 9 - 2...
  • Page 31 • BOTTOM VIEW 9 - 3...

  • Page 32: Main Unit

    9-5 MAIN UNIT • TOP VIEW ICOM C111 C186 C102 C107 C175 C174 [TX-PWR] C173 C172 C185 C106 R192 C198 C197 R144 [ MOD ] R138 [ REF ] VR-A/B R139 C203 C204 EXT-MIC C123 C127 C125 from/to Optional unit...
  • Page 33 • BOTTOM VIEW to LOGIC board J2 C271 C115 C118 C187 C116 SP + SP - C104 R134 C272 C255 C159 C217 C262 R121 C261 R122 R113 R201 R195 R196 C222 R194 C155 R193 R168 9 - 5...

  • Page 34: Hm-127 (Optional Unit)

    9-6 HM-127 (OPTIONAL UNIT) • TOP VIEW 9 - 6...
  • Page 35 • BOTTOM VIEW PWRC RRXDA RTXDA PTTC MICG AF/MIC to IC-M402 MAIN unit J2 and LOGIC board J1 9 - 7...

  • Page 36: Block Diagram

    SECTION 10 BLOCK DIAGRAM FRONT UNIT MAIN UNIT FI3: ALFY450E CERAMIC BPFV IC1: EXT.SP OPTION TA31136FN Q17: 2SD1664 Q D10: XB15A308 Q28: 2SC2714 Y D15: XB15A308 EXTERNAL SPEAKER 2SC4116 BL FI1,2: FL310 3SK272 Q27: 2SC4226 R25 WXDEC 2nd IF XTAL D8, D9: HSM88ASR HM-129 Q10:...

  • Page 37: Voltage Diagram

    SECTION 11 VOLTAGE DIAGRAM 11-1 LOGIC BOARD DTRS DTRS R20 18 k DIM3 TTR5341 2SB1132 R CH16 CH16 10 k SEG26 CHWX CHWX SEG27 12 k SEG12 39 k 100 k 100 k 18 k 100 k 100 k SEG13 DIM2 BAND EXTENTION FY1101 F-TR...

  • Page 38: Main Unit

    11-2 MAIN UNIT 1.00V at 3dB RX R158 22 0.5Vp-p at 1kHz 3kHz DEV 3.55V L28 82 nH 0.001 100 P R25 100 1.5 k R14 1.2 k R165 C258 0.82 H IC2 UPD3140GS C226 0.10 H C252 C227 C228 R155 100 k 470 P...
  • Page 39 11-3 HM-127 (OPTIONAL UNIT) CHASSIS MAIN UNIT PWRSW TA7368F POUT 036D0801 PWGND 10KEY PREGND PHASE RIPPLE 0.047 SML-311YT SML-311YT 10KEY SML-311YT 2SJ144 10KEY SKQLLC SKQLLC SKQLLC DOWN M62429FP DS10 470k SML-311YT 10KEY VIN1 VIN2 VOUT1 VOUT2 100k 100k VRDAT SKB-2746 LPC DATA MICG FY1101F-TR...
  • Page 40 11-4 HM-129 470 P 12 k CHASSIS UNIT W1 MICG MICG to MAIN unit J4 PTTG 6.8 k KEYM to LOGIC board J3 15 k UP_ON 2.0V DN_ON 3.0V 16/9_ON 3.8V 33 k 16/9 11 - 4...
  • Page 42 S-13716IZ-CD 1-1-32, Kamiminami, Hirano-ku, Osaka, 547-0003, Japan © 2001 Icom Inc.

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