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16 V. This will ruin the at the time of publication. transceiver. 2 versions of the IC-M45/IC-M45EURO have been designed. DO NOT expose the transceiver to rain, snow or any liquids. This service manual covers each version.
TABLE OF CONTENTS SECTION SPECIFICATIONS VHF MARINE CHANNEL LIST ..........1-2 SECTION DISASSEMBLY INSTRUCTIONS SECTION...
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• Mode : 16K0G3E (FM) • Usable channels Channel Model Version USA CAN [USA] IC-M45 [USA-1] [ITA] IC-M45EURO [FRA] • Power supply requirement : 13.8 V DC ±15% (negative ground) • Usable temperature range : –20˚C to +60˚C; –4˚F to +140˚F •...
SECTION 2 DISASSEMBLY INSTRUCTIONS • • REMOVING THE CASE REMOVING THE MAIN UNIT 1 Unscrew the 4 screws, A. 1 Unsolder DC cable (2 points) and antenna connector, B (3 points), as shown below. Note: When replacing the screw, 10–12 kg of torque MUST 2 Unscrew 2 screws, C, and 7 screws, D, to remove the be applied to ensure water resistance.
SECTION 3 CIRCUIT DESCRIPTION 3-1 RECEIVER CIRCUITS 3-1-4 2ND IF AND DEMODULATOR CIRCUITS The 2nd mixer circuit converts the 1st IF signal to a 2nd IF 3-1-1 ANTENNA SWITCHING CIRCUIT signal. A double superheterodyne system (which converts The antenna switching circuit functions as a low-pass filter receive signals twice) improves the image rejection ratio and while receiving and as resonator circuit while transmitting.
When the weather alert function is activated and a 1050 Hz amplifier (IC2). alert tone from an NOAA weather radio broadcast is received, the IC-M45 emits beep tones and indicates flash- ing “ALT” on the display to inform of an emergency weather 3-2-4 POWER AMPLIFIER CIRCUIT report on the air.
3-3 PLL CIRCUITS The phase detector compares the input signal with a refer- ence frequency, and then outputs the out-of-phase signal 3-3-1 GENERAL (pulse-type signal) from pin 13. The PLL circuit provides stable oscillation of the transmit fre- quency and receive 1st LO frequency. The PLL circuit com- The pulse-type signal is converted into DC voltage (lock pares the phase of the divided VCO frequency to the refer- voltage) at the loop filter (R34, R37, R38, C64, C73), and...
3-5 PORT ALLOCATIONS 3-5-1 CPU (LOGIC unit; IC1) 3-5-2 OUTPUT EXPANDER (MAIN unit; IC7) Port Port Description Description number name number name Input port for the connected power Outputs the R5 regulator (Q19, Q20) LBATT supply voltage detection (low voltage control signal.
SECTION 4 ADJUSTMENT PROCEDURES 4-1 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...
4-2 PLL ADJUSTMENTS ADJUSTMENT MEASUREMENT POINT ADJUSTMENT ADJUSTMENT CONDITION VALUE UNIT LOCATION UNIT ADJUST LOCK • Operating channel : ch16 MAIN Connect a digital 2.6 V MAIN • Receiving multi-meter or oscil- VOLTAGE loscope check point CP1. • Operating channel : ch16 Connect a digital 2.8 V •...
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DC power supply – 13.8 V /15 A to DC cable Black Output power adjustment for [Low] Output power adjustment for [High] Sensitivity R130 adjustment Frequency deviation adjustment C117 Reference frequency PLL lock voltage adjustment check point for [RX] PLL lock voltage check point for [TX] Sensitivity check point...
SECTION 8 BOARD LAYOUTS 8-1 LOGIC, VR-A AND VR-B UNITS 8-1-1 TOP VIEW • LOGIC UNIT SP— SP— BEEP ICF3 HANG TXDET OEX. OE P. STB OEX.STB TONE S.METER PTT. S UNLK DATA KEY.M DATAM DATAS FROM SQLV MICROPHONE BUSY F.
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8-1-2 BOTTOM VIEW • LOGIC UNIT • • VR-B UNIT VR-A UNIT 8 - 2...
10-2 MAIN UNIT Rx: 2.2V TONE 1.5 k 0.001 100 k 0.47 H X2 CDBCA450CX24 C42 100 P 0.001 0.22 D5 1SS321 100 k FI1b FL-202 FI1a FL-202 R157 C199 68 P 0.001 0.001 0.01 L6 LS-491 0.001 22 k 820 k LA-253 C201...
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