Icom IC-M304 Service Manual
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Icom IC-M304 Service Manual

Vhf marine transceiver
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VHF MARINE TRANSCEIVER
iC-m304
S-14311XZ-C1
Dec. 2006

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Summary of Contents for Icom IC-M304

  • Page 1 VHF MARINE TRANSCEIVER iC-m304 S-14311XZ-C1 Dec. 2006...
  • Page 2 8. READ the instructions of test equipment thoroughly before connecting equipment to the transceiver. Icom, Icom Inc. and logo are registered trademarks of Icom Incorporated (Japan) in the United States, the United Kingdom, Germany, France, Spain, Russia and/or other countries.

  • Page 3: Table Of Contents

    CONTENTS SECTION SPECIFICATIONS SECTION INSIDE VIEWS SECTION DISASSEMBLY INSTRUCTIONS SECTION CIRCUIT DESCRIPITON RECEIVER CIRCUITS............4-1 TRANSMITTER CIRCUITS .

  • Page 4: Specifications

    SECTION 1 SPECIFICATIONS GENERAL • Frequency coverage : TX 156.025–157.425 MHz 156.050–163.275 MHz • Type of emission : 16K0G3E (FM), 16K0G2B (DSC) • Channel spacing : 25 kHz : 50 Ω (Nominal) • Antenna impedance • Operating temperature range : –20˚C to +60˚C; –4˚F to +140˚F •...

  • Page 5: Channel List

    • CHANNEL LIST . y l . y l , s l y l l c i l 1 - 2...
  • Page 6 SECTION 2 INSIDE VIEWS • MAIN UNIT TX POWER MODULE (IC4: S-AV35A) DSC DECODER (IC3: NJM2211M) IDC/LPF (IC10: NJM4558M) MIC MUTE SWITCH (IC7: TC7W66EU) 2nd IF filter (FI3: LT450EW) IF IC 1st IF filters PLL IC (IC1: TA31136FN) (FI1: FL-368, (IC8: uPD3140GS) FI2: FL-399A) •...
  • Page 7 SECTION 3 DISASSEMBLY INSTRUCTION 1. Removing the front panel 3. Removing the LOGIC UNIT q Unscrew 8 screws A, as shown below, and then remove q Disconnect 2 cables I and K. w Unsolder 2 points H. the case in the direction of the arrow. e Unscrew 4 screws J, to remove the LOGIC UNIT.

  • Page 8: Receiver Circuits

    Hz alert tone from an NOAA weather radio broadcast is desired frequency will be passed through two crystal filters received, the IC-M304 emits beep tones and indicates at the next stage of the mixer. flashing “ALT” on the display to inform of an emergency weather report on the air.

  • Page 9: Transmitter Circuits

    4-1-5 AF AMPLIFIER CIRCUIT 4-2 TRANSMITTER CIRCUITS (MAIN AND FRONT UNITS) 4-2-1 MICROPHONE AMPLIFIER CIRCUIT The AF amplifier circuit amplifies the detected signals to (MAIN UNIT) drive a speaker. The AF circuit includes an AF mute circuit The microphone amplifier circuit amplifies audio signals with for the squelch.

  • Page 10: Pll Circuits

    4-2-5 APC CIRCUIT (MAIN UNIT) applied voltage controls the differential amplifier output (Q21, The APC circuit stabilizes transmit output power. pin 1) and the bias voltage control (Q23). Thus the APC circuit maintains a constant output power. The RF output signal from the power amplifier (IC4) is detected at the power detector circuit (D21, D22, L31) and is then applied to one of the differential amplifier inputs (Q21, pin 3) via the High/Low control circuit (Q22, R137).

  • Page 11: Dsc Circuits

    4 steps LCD backlight (DS2–DS7). • UART PORT IC-M304 has the UART port which is used for cloning data and NMEA interface. The signals pass through the photo coupler circuit (IC2), and are then applied to the buffer amplifier (IC3, pin 2).

  • Page 12: Port Allocations

    4-7 CPU PORT ALLOCATIONS Port name Description Port name Description Input port for the [DISTRESS] key (LOGIC DTRS BOARD; S9). Input port for keys on HM-150B/SW. Low: [DISTRESS] key is pushed. Approx. 2.02 V: [Y] key is pushed. KEYM Outputs AF (Public Address) mute signal to Approx.

  • Page 13: Preparation

    RF power meter Blue: Speaker (+) 0.1–30 W/50 SINAD meter Gray: Speaker (−) Frequency counter Speaker (4 Ω) − Red: Positive (+) Power supply 13.8 V/10 A − Attenuator Black: Negative (−) 40 dB deviation meter IC-M304 5 - 1...

  • Page 14: Frequency Adjustment

    5-2 FREQUENCY ADJUSTMENT ADJUSTMENT ADJUSTMENT OPERATION VALUE CONDITION LOCK 1 • Channel : CH16 (156.800 MHz) Connect a DC voltmeter to the check point ‘LV.’ 1.3–2.3 V VOLTAGE • Receiving (Verify) (Verify) 2 • Channel : CH16 (156.800 MHz) 1.4–2.4 V •...

  • Page 15: Transmit Adjustment

    5-3 TRANSMIT ADJUSTMENT ADJUSTMENT ADJUSTMENT CONDITION OPERATION VALUE TRANSMIT 1 • Channel : CH16 (156.800 MHz) Adjust R135 (PWR). 23.5 W OUTPUT • Output power : High POWER • Connect an RF power meter to the ant- enna connector. • Transmitting DEVIATION 1 •...

  • Page 16: Receive Adjustment

    5-4 RECEIVE ADJUSTMENT VALUE ADJUSTMENT ADJUSTMENT CONDITION CONNECTION RECEIVE 1 • Channel : CH16 (156.800 MHz) 1) Connect a DC voltmeter to the check point ‘RSSI.’ Maximum SENSITIVITY • [SQUELCH] : Open 2) Adjust in sequence L6, L7, L8 and L9. voltage (Max.

  • Page 17: Main Unit

    SECTION 6 PARTS LIST [LOGIC UNIT] [REPLACEMENT UNITS] ORDER DESCRIPTION ORDER NO. UNIT NAME LOCATION 0329890101 U M304 #01 FRONT (FRONT+LOGIC+VR+SQL) [Black] 4030006850 S.CER C1608 JB 1H 471K-T 9/38.2 4030006860 S.CER C1608 JB 1H 102K-T 41.8/13.3 0329890201 U M304 #02 FRONT (FRONT+LOGIC+VR+SQL) 4030006850 S.CER C1608 JB 1H 471K-T 51.7/12.1 [Super White]...
  • Page 18 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION 6110001600 COL LA-243 R111 7030003560 S.RES ERJ3GEYJ 103 V (10 k) 47/64 6150003821 COL LS-440-LF R112 7030003580 S.RES ERJ3GEYJ 153 V (15 k) 49.6/60.2 6150003821 COL LS-440-LF R113 7030003370 S.RES ERJ3GEYJ 271 V (270) 50.9/64 6150003821 COL LS-440-LF...
  • Page 19 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION 4030006860 S.CER C1608 JB 1H 102K-T 100.3/38.7 C194 4030007130 S.CER C1608 CH 1H 101J-T 41.3/70.7 4030009350 S.CER C1608 CH 1H 3R5B-T 91.6/26.5 C198 4030007130 S.CER C1608 CH 1H 101J-T 26.1/60.9 4030006860 S.CER C1608 JB 1H 102K-T 92.1/32.1 C199...

  • Page 20: Logic Unit

    SECTION 7 MECHANICAL PARTS AND DISASSEMBLY [CHASSIS PARTS] [MAIN UNIT] ORDER ORDER DESCRIPTION QTY. DESCRIPTION QTY. 6510004880 MR-DSE-01 6510024601 S5B-PH-K-S (LF) (SN) 8900012331 OPC-1258A 8900012401 OPC-1264A 7120000470 ERDS2T0 8010019302 2685 CHASSIS-2 8930061050 2685 R-BUSH PLATE MP1* 8510011111 1922 VCO CASE-1 8510015570 2685 CASE [Black] 8510011101 1922 VCO COVER-1...
  • Page 21 137.0 (5 ⁄ MP16(C) MP4(C) MP16(C) MP16(C) MP6(F) LOGIC UNIT MP11(C) MP16(C) 153.0 (6 ⁄ 42.2 86.3 (3 ⁄ ⁄ Unit: mm (inch) EP2(L) MP1(L) MP14(C) MP3(L) DS1(L) MP16(C) MP2(L) J1(C) MP6(C) MP7(C) W1(C) NOTE 1 MP1(F) MP3(C) NOTE 2 MC1(F) NOTE 1 W1(C)
  • Page 22 SECTION 8 SEMICONDUCTOR INFORMATION • TRANSISTERS AND FETs • DIODES • DTC114TUA • KTA1664Y • 2SC4215 • 2SC4226 • 3SK131 • 1SS355 • KDS122 • 1SS321 • DSA3A1 • HSM88ASRTR (Marking: 04) (Marking: QO) (Marking: XX) (Marking: R24) (Marking: V13) (Marking: 5D) (Marking: C3) (Marking: F9)
  • Page 23 SECTION 9 BOARD LAYOUTS • MAIN UNIT (TOP VIEW) • LOGIC UNIT (TOP VIEW) UNLK PDATA PSTB • HM-164B/SW/G SQLC TXDET TMUTE KEYM • VR UNIT (TOP VIEW) SEND PTTC DSCDEC RMUTE WXDEC DSCENC VOL1 VOL2 MICG SQLV BPLVL BEEP SP−...
  • Page 24 • LOGIC UNIT (BOTTOM VIEW) • MAIN UNIT (BOTTOM VIEW) MP13 (FRONT UNIT) To J1 (MAIN UNIT) • VR UNIT (BOTTOM VIEW) • SQL UNIT (BOTTOM VIEW) SP− 9 - 2...
  • Page 25 SECTION 10 BLOCK DIAGRAM FRONT UNIT EXT SP HM-164B/SW/G Q5:KTC4075 Frequency range WXDEC T X:156.025–157.425MHz RX:156.050–163.275MHz IC6:LA4425A IC3:NJM2211M FI3:LT450EW I NT SP DSCDEC CERAMI C AM P DECODER I C1:TA31136FN VR UNIT Q4:KTC4080 FI1: FL-368 D1,D2: I C7B:TC7W66F U Q6,7:KTC4075x2 D 8:MA742 FI2: FL-399A...
  • Page 26 SECTION 11 VOLTAGE DIAGRAM • LOGIC UNIT SDT-DM2360 DIM MAX:12.27V CP10S KTA1664 CP10S KTC4075 KTC4075 3.31V BEE P BPLVL SQLV SEG6 DSCENC P67/AN7 SEG13 KEYM SEG18 WXDEC RMUTE P66/AN6 SEG14 TXDET SEG19 DSCDEC PTTC P65/AN5 SEG15 SQLV SEG20 P64/AN4 SEG16 SEG3 SEND KEYM...
  • Page 27 • MAIN UNIT RSSI MP 3 LS-440 R:2.14V R:7.55V R:3.48V 2685 KTC4075 LS-440 JTB450C24 0.5P 0.022 100P LS-440 0.01 1.5K C1 3 0.033 3SK131 LOCK 0.01 3SK13 1 C100 FL-399A FL-368 LOOP FI 2 FI 1 R:4.26V R:0.23V 100K C102 DATA R:3.62V R:0.42V...

  • Page 28: Hm-164B/Sw/G

    • VOLTAGE DIAGRAM • MAIN UNIT PARTS LIST SECTION 12 HM-164B/SW/G ORDER DESCRIPTION LOCATION 0.22u 6180003720 COL SP0203-R22K-PF 0.22U 6180003720 COL SP0203-R22K-PF 0.22U 0.22u • REPLACEMENT UNIT • DIMENTIONS W1 (CHASSIS) [PTT] MICG ORDER NO. UNIT NAME 7010007590 RES RD1/4S 123JTA 7010007600 RES RD1/4 682JTA KEYM...
  • Page 30 S-14311XZ-C1 1-1-32, Kamiminami, Hirano-ku, Osaka 547-0003, Japan © 2006 Icom Inc.
  • Page 31 • REPLACEMENT UNIT INFORMATION FOR IC-M304 HM-164 ORDER NO. UNIT NAME Optional product HM-164B [Black] Optional product HM-164SW [Super White] Optional product HM-164G [Gray] FRONT UNIT (Incl. LOGIC, VR, SQL UNITS and HM-164) ORDER NO. UNIT NAME 0329890101 U M304 #01 FRONT (FRONT+LOGIC+VR+SQL, and HM-164B)

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