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This service manual describes the latest service information NEVER connect the transceiver to an AC outlet or to a DC for the IC-400PRO UHF TRANSCEIVER at the time of publi- power supply that uses more than 16 V. This will ruin the transceiver.
SECTION 3 DISASSEMBLY INSTRUCTIONS • Opening case and removing the front unit Unscrew 8 screws F. Unscrew 4 screws A, and remove the bottom cover. Remove the filter case G. Disconnect the flat cable B from J2. Unscrew the screw H. Disconnect the cable C from J7.
SECTION 4 CIRCUIT DESCRIPTION 4-1 RECEIVER CIRCUITS 4-1-3 1ST MIXER AND 1ST IF CIRCUITS (MAIN UNIT) 4-1-1 ANTENNA SWITCHING CIRCUIT The 1st mixer circuit converts the received signals to a fixed (MAIN UNIT) frequency of the 1st IF signal with the PLL output frequency. The antenna switching circuit functions as a low-pass filter By changing the PLL frequency, only the desired frequency while receiving and as resonator circuit while transmitting.
4-1-5 AF AMPLIFIER CIRCUIT (MAIN UNIT) 4-2 TRANSMITTER CIRCUITS The AF amplifier circuit amplifies the demodulated AF sig- 4-2-1 MICROPHONE AMPLIFIER CIRCUIT nals to drive a speaker. (MAIN AND FRONT UNITS) The microphone amplifier circuit amplifies audio signals The AF signals from the FM IF IC (IC1, pin 9) are applied to within +6 dB/octave pre-emphasis characteristics from the the active filter circuit (IC16).
4-2-4 POWER AMPLIFIER CIRCUIT (MAIN UNIT) 4-3 PLL CIRCUITS The power amplifier circuit amplifies the driver signal to an 4-3-1 PLL CIRCUIT (MAIN UNIT) output power level. A PLL circuit provides stable oscillation of the transmit fre- quency and receive 1st LO frequency. The PLL output com- The RF signal from the drive amplifier (Q8) is passed pares the phase of the divided VCO frequency to the refer- through the low-pass filter circuit (L18, L43, C89, C90, C92,...
4-4 POWER SUPPLY CIRCUITS 4-5 PORT ALLOCATIONS 4-4-1 VOLTAGE LINES (MAIN UNIT) 4-5-1 CPU (FRONT UNIT; IC1) Port Line Description Description number name The voltage from a DC power supply. TEMP Input port for the internal temperature. The same voltage as the HV line which is con- Input port for the low voltage detection trolled by the power switching circuit (Q23, Q24).
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CPU-Continued 4-5-2 OUTPUT EXPANDER (MAIN UNIT; IC17) Port Port Description Description number name number name I/O ports for the optional board control Outputs transmit/receive control signal. OPT3– 44–46 OPT1 signals. High: While receiving. Outputs audio output control signal. Input port for the clock signal from the AFON High: While receiving.
• At least 16 MB RAM and 10 MB of hard disk space I STARTING SOFTWARE ADJUSTMENT • 640×480 pixel display (800×600 pixel display recommend- q Connect IC-400PRO and PC with *OPC-1122 JIG CABLE w Turn the transceiver power ON.
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I 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 : 1–50 W Frequency range...
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• SCREEN DISPLAY EXAMPLE CS-400PRO ADJ Rev.1.0 File Option COM 1: OPEN Connect Reload (F5) Disp para [A / D] [D / A] : 178 : B2h : 19.96 V BPF T1 : 197 : 32h : 0.98 V TEMPS : 177 : B1h : 26.44 ’C T2/POW : 172 : 32h : 0.98 V LVIN...
5-2 PLL ADJUSTMENT MEASUREMENT ADJUSTMENT ADJUSTMENT ADJUSTMENT CONDITIONS VALUE UNIT LOCATION UNIT ADJUST PLL LOCK • Operating freq. : 450.000 MHz MAIN Connect a digital multi- 1.0 V MAIN C133 VOLTAGE • Receiving meter or an oscillo- scope to the check point, “LV”.
5-3 SOFTWARE ADJUSTMENT Select an operation using [↑] / [↓] keys, then set specified value using [←] / [→] keys on the connected computer keyboard. MEASUREMENT ADJUSTMENT ADJUSTMENT CONDITION VALUE UNIT LOCATION REFERENCE • Operating freq. : 500.000 MHz Rear Loosely couple a frequency 500.0000 MHz FREQUENCY...
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SOFTWARE ADJUSTMENT – continued Select an operation using [↑] / [↓] keys, then set specified value using [←] / [→] keys on the connected computer keyboard. MEASUREMENT ADJUSTMENT ADJUSTMENT CONDITION VALUE UNIT LOCATION • Operating freq. : 450.000 MHz MAIN Connect a SINAD meter with a Minimum distortion 4 Ω...
5-4 TRIMMER ADJUSTMENT • Make this adjustment if necessary (For example, when beep sound is too loud or too soft). • BE CAREFUL!: 5-tone calling beep sound becomes loud or soft when beep volume adjusts to loud or soft. MEASUREMENT ADJUSTMENT ADJUSTMENT ADJUSTMENT CONDITIONS...
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SECTION 11 VOLTAGE DIAGRAMS 11-1 FRONT UNIT DS11 FRONT UNIT L2-0607TAY 5.0V Explanatory notes R51 100k HANG VOLTAGE LINE TX LINE MA2S111 RX LINE C79 0.1 COM3 SEG22 COM3 COM4 SEG21 COM4 CPU5V SEG20 S-80942CNMC-G9C 5.0V TEMP P86/AN6 P70/SCK3_2 CPU5V SEG19 BATV CPU5V...
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