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VHF MARINE TRANSCEIVER
iC-m88
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INTRODUCTION This service manual describes the latest service information for the IC-M88 VHF MARINE TRANSCEIVER at the time of publication. Model Version Symbol Battery pack FM I / S USA NO BP-227 U.S.A. IC-M88 USA-1 YES BP-227FM NO BP-227 S.E. Asia SEA To upgrade quality, all electrical or mechanical parts and inter- nal circuits are subject to change without notice or obligation. DANGER NEVER connect the transceiver to an AC outlet or a DC power supply that uses more than 8.3 V. This will
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TABLE OF CONTENTS SECTION 1 SPECIFICATIONS SECTION 2 INSIDE VIEWS SECTION3 DISASSEMBLYINSTRUCTIONS SECTION 4 CIRCUIT DESCRIPTION 4 - 1 RECEIVER CIRCUITS ................................................................................................... 4 - 1 4 - 2 TRANSMITTER CIRCUITS ............................................................................................ 4 - 2 4 - 3 PLL CIRCUITS................................................................................................
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SECTION 1 SPECIFICATIONS GENERAL Frequency coverage : TX: 156.025–157.425 MHz, RX: 156.050–163.275 MHz [MARINE] TX/RX: 146.000–174.000 MHz [LMR] Number of free channels : 22 channels Type of emission : 16K0G3E (Wide; 25 kHz) [MARINE] 16K0F3E (Wide; 25 kHz), 8K50F3E (Narrow; 12.5 kHz) [LMR] Antenna connector : SMA (50 Ω) Power supply requirement : BP-227/FM (7.2 V DC, negative ground) Current drain (approx.) : Transmit at High (5.0 W) 1.6 A at Middle (3.0 W) 1.
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VHF MARINE CHANNEL LIST Channel No. Frequency (MHz) Channel No. Frequency (MHz) Channel No. Frequency (MHz) USA INT CAN Transmit Receive USA INT CAN Transmit Receive USA INT Transmit Receive 01 01 156.050 160.650 21A 21A 157.050 157.050 73 73 156.675 156.675 01A 156.050 156.050 22 157.100 161.700 74 74 156.725 156.725 1 02 02 156.100 160.700 22A 22A 157.100 157.100 77* 77 156.875 156.875 03 03 156.150 160.750 23 23 157.150 161.750 78 156.925 161.525 03A 156.150 156.150 23A 157.150 157.150 78A 1
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SECTION 2 INSIDE VIEWS • LOGIC UNIT Bottom view *: Located in another side of this point. AF mute circuit Q441* : 2SC4116 Q442* : CPH3403 Q443 : CPH3403 IN/EXT microphone switch Q444 : DTC144EU (Q461, Q462: UN911H) EEPROM (IC591*: HN58X2416TI) Microphone amplifier (IC471: NJM2904V) CPU AF mute (IC661: µPD780316GC-511-9EB) (IC481: TC4W66FU) S5V regulator (Q561: 2SA1588) M5V regulator Q551: 2SB1132 Q552: XP6501 Q553: DTC144EU • MAIN UNIT Bottom view Top view Antenna switching circuit D13
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SECTION 3 DISASSEMBLY INSTRUCTIONS 1. Removing the chassis panel q Remove nut A. w Unscrew 2 screws B (2 × 8 mm, black) and 3 screws C C (2 × 4 mm, black) from the chassis. e Take off the chassis in the direction of the arrow. B y NOTE:* Tighten the screws in order of a number (q–y) e when assembling. C r w q A Chassis C t 2. Removing the LOGIC unit. 3. Removing the MAIN unit q Unplug the cable from J281 on the MAIN unit to separate q Unsolder 4 leads of contact spring and antenna connector the
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SECTION 4 CIRCUIT DESCRIPTION The 1st IF signal is applied to a 2nd mixer section of the 4-1 RECEIVER CIRCUITS FM IF IC (IC231, pin 16). The signal is then mixed with a 4-1-1 ANTENNA SWITCHING CIRCUIT 2nd LO signal for conversion into a 450 kHz 2nd IF signal. (MAIN UNIT) The antenna switching circuit functions as a low-pass filter IC231 contains the 2nd mixer, limiter amplifier, quadrature while receiving and as resonator circuit while transmitting. detector and active filter circuits. A
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4-1-5 SQUELCH CIRCUIT 4-2-2 MODULATION CIRCUIT (MAIN UNIT) The modulation circuit modulates the VCO oscillating signal (MAIN AND LOGIC UNITS) (RF signal) using the microphone audio signals. The noise squelch circuit cuts out AF signals when no RF signals are received. By detecting noise components in the The audio signals “MOCON” change the reactance of D39 AF signals, the squelch circuit switches the AF mute switch. to modulate an oscillated signal at the TX VCO circuit (Q51, D35–D38,
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4-4 POWER SUPPLY CIRCUITS 4-3 PLL CIRCUIT (MAIN UNIT) VOLTAGE LINES 4-3-1 GENERAL The PLL circuit provides stable oscillation of the transmit LINE DESCRIPTION frequency and receive 1st LO frequency. The PLL output HV The voltage from the attached battery pack. compares the phase of the divided VCO frequency to the reference frequency. The PLL output frequency is controlled The same voltage as the HV line (battery by the divided ratio (N-data) of a programmable divider. IC1 voltage) which is
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4-5 PORT ALLOCATIONS 4-5-1 CPU (LOGIC UNIT; IC661) Pin Port Pin Port Description Description number name number name 1 BEEP Outputs beep audio signals. Outputs scrambler mute signal for the STXMS 79 AF mute circuit (IC481, pin 3). Outputs strobe signals for the scrambler 2 VSSTB Low : While scrambler is muting. IC (MAIN unit; IC381, pin 10). Outputs mic mute signal for the AF Outputs strobe signals for the 3 EXSTB mute circuit (IC481, pin 7). expander IC (MAIN unit; IC341, pin 1). MICMS
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4-5-2 EXPANDER IC (MAIN UNIT; IC341) CPU–Continued Pin Port Pin Port Description Description name number name number Input port for the [DOWN] key. Outputs the AF mute switch (IC281, 111 DOWN Low : While [DOWN] key is pushed. pin 3) control signal. 5 SRXMS Low : While the scrambler decording Input port for the [CH/WX] key. signal is muted. 112 CH/WX Low : While [CH/WX] key is pushed. Outputs the AF mute swtich (IC281, Input port for the [16/9] key. 6 DETMS pin 7) control signal.signal.
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SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION When adjusting IC-M88, optional OPC-966 CLONING CABLE, optional RS-232C CABLE and optional CS-M88 adj ADJUSTMENT SOFTWARE are required. EQUIPMENT GRADE AND RANGE EQUIPMENT GRADE AND RANGE Output voltage : 7.2 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 Frequency range : 300–3000 Hz Audio generator RF power meter Frequency range : 100–
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CONNECTION Standard signal generator to the antenna connector 0.1 V to 32 mV ( 127 dBm to 17 dBm) FM Attenuator deviation meter 40 dB or 50 dB CAUTION: DO NOT transmit while RF power meter SSG is connected to the 0.1 10 W/50 antenna connector. Frequency counter Personal computer to an RS-232C port Audio generator SINAD meter DB9 female plug *OPC-966 RS-232C cable (straight) (JIG CABLE) Speaker (8 ) Add a jumper wire here OPC-966 (Cloning cable) PTTE PTT MIC + MICE Audio generator
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SCREEN EXAMPLE CS-M88 ADJ Rev.1.0 File Option 2 COM 1: OPEN Connect Reload (F5) Disp para 1 [A / D] [D / A] 4 BATT : 120 : 78h : 7.53 V FRQCON : 127 : 7Fh : 2.49 V NOIS : 59 : 3Bh : 1.16 V T1/POW : 92 : 5Ch : 1.80 V SD : 44 : 2Ch : 0.86 V T2 : 127 : 7Fh : 2.49 V 3 5 LVIN : 119 : 77h : 2.33 V T3 : 86 : 56h : 1.69 V TEMPS : 178 : B2h : 26.86 ’C T4 : 117 : 75h : 2.29 V TXDET : 0 : 00h : 0.00 V Dev : 0 : 00h : 0.00 V WET : 255 : FFh : 5.00 V CTCS BL : 0 : 00h : 0.00 V SQL LEV : 76 : 4Ch : 1.49 V
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5-2 SOFTWARE ADJUSTMENT Select an operation using [ ] / [ ] keys, then set specified value using [←] / [→] keys on the connected computer keyboard. ↓ ↑ MEASUREMENT ADJUSTMENT ADJUSTMENT CONDITION VALUE ADJUSTMENT UNIT ADJUSTMENT CONDITION UNIT LOCATION PLL LOCK 1 Operating channel : center frequency MAIN Connect the digital multimeter to 1.5–3.0 V (Verify) VOLTAGE Receiving the check point LV. 2 Operating channel : center frequency 1.8–3.3 V (Verify) Connect the RF power met
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MAIN UNIT TOP VIEW LV PLL lock voltage check point 5 - 5
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SOFTWARE ADJUSTMENT – continued Select an operation using [ ] / [ ] keys, then set specified value using [←] / [→] keys on the connected computer keyboard. ↓ ↑ “SQUELCH LEVEL ADJUSTMENT” must be performed after “RX SENSITIVITY ADJUSTMENT” is finished. “SQUELCH LEVEL ADJUSTMENT” must be performed when “RX SENSITIVITY ADJUSTMENT” is adjusted. MEASUREMENT ADJUSTMENT ADJUSTMENT CONDITION VA VALUE LUE ADJUSTMENT CONDITION ADJUSTMENT UNIT LOCATION RX 1 Operating frequency : center f
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SECTION 6 PARTS LIST [VR UNIT] [LOGIC UNIT] REF ORDER H/V REF ORDER H/V DESCRIPTION M. DESCRIPTION M. NO. NO. LOCATION NO. NO. LOCATION Q552 1590001190 S.TR XP6501-(TX) .AB B 13.3/23.7 R801 7210003130 VAR TP76N97N-13F-10KA-2497 Q553 1590000430 S.TR DTC144EUA T106 B 20.1/20.1 Q561 1510000670 S.TR 2SA1588-GR (TE85R) B 22/16 Q651 1590001770 S.TR XP1213 (TX) B 27.4/16.9 W801 8900011900 CBL OPC-1192 W802 8900011910 CBL OPC-1193 [US], [SEA] 8900012
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[LOGIC UNIT] [LOGIC UNIT] REF ORDER H/V REF ORDER H/V DESCRIPTION M. DESCRIPTION M. NO. NO. LOCATION NO. NO. LOCATION R553 7030003600 S.RES ERJ3GEYJ 223 V (22 kΩ ) B 12.4/19.4 C602 4030006980 S.CER C1608 CH 1H 070D-T B 42.8/37.5 R561 7030003560 S.RES ERJ3GEYJ 103 V (10 kΩ ) B 20.1/16.1 C603 4030007070 S.CER C1608 CH 1H 330J-T B 44.1/36.1 R562 7030003520 S.RES ERJ3GEYJ 472 V (4.7 kΩ ) B 22.3/20.1 C604 4030006900 S.CER C1608 JB 1H 103K-T B 47/34.5 R571 7030005930 S.RES ERJ3GE
