Service manual

VCO
VCOVCO
VCO (VOLTAGE CONTROL OSCILLATER)
(VOLTAGE CONTROL OSCILLATER)(VOLTAGE CONTROL OSCILLATER)
(VOLTAGE CONTROL OSCILLATER) CIRCUIT
CIRCUITCIRCUIT
CIRCUIT
OUTPUT FROM VCO (Q16) IS AMPLIFIED AT BUFFER AMPLIFIER (Q15). THEN IT IS SENT
TO Tx/Rx SWITCHED (D8, D6). Rx LO SIGNAL IS APPLIED TO THE 1ST MIXER CIRCUIT
(Q5) THROUGH LOW PASS FILTER, AND Tx SIGNAL IS APPLIED TO PRE-DRIVE
AMPLIFIER (Q19). A PART OF VCO OUTPUT IS USED AGAIN AT PLL IC (U5, PIN 6) VIA
C146.
DSC
DSCDSC
DSC (DIGITAL SELECTIVE CALLING) MODULATING CIRCUIT
(DIGITAL SELECTIVE CALLING) MODULATING CIRCUIT(DIGITAL SELECTIVE CALLING) MODULATING CIRCUIT
(DIGITAL SELECTIVE CALLING) MODULATING CIRCUIT
MODULATING SIGNAL FROM CPU IS DELIVERED THROUGH LOW PASS FILTER (U14/B)
WITH + 6 dB/OCTAVE FEATURE. SIGNAL FROM LOW BAND FILTER (U14/B) IS
DELIVERED THROUGH CROSSTALK FILTER (U15/B), IN ORDER TO REMOVE
UNNECESSARY SIGNALS OVER 3 kHz. FILTERED DSC SIGNAL IS APPLIED TO TX
MODULATING CIRCUIT VIA MODULATION FACTOR ADJUSTER (VR3).
12.
12. 12.
12. TROUBLE SHOOTING METHOD
TROUBLE SHOOTING METHODTROUBLE SHOOTING METHOD
TROUBLE SHOOTING METHOD
 WHEN POWER IS NOT TURNED ON
> FUSE IS BROKEN, OR VOLTAGE IS NOT SUPPLIED TO RADIO.
- CHECK BREAKING, CRUSH, SHORT CIRCUIT, POWER GROUNDING, ETC OF
POWER CABLE.
- AFTER CHECKING WIRE LOSS, CHANGE 10A FUSE (THERE ARE 2 SPARE
FUSES).
- CHECK BATTERY VOLTAGE. VOLTAGE SHOULD BE DC 13.6V (±10%).
> POWER IS NOT TURNED ON.
- CHANGE FCC DUE TO CONNECTING ERROE
 WHEN FUSE IS CUT, WHEN SWITCH IS TURNED ON
> WIRE OF POWER MAY BE CONNECTED CONVERSELY.
- CHECK IF RED LINE IS CONNECTING BATTERY'S (+) TERMINAL, AND
BLACK LINE IS CONNECTING BATTERY'S (-) TERMINAL.
 SOUND DEFECTS.
> WHEN NO SOUND IS HEARED FROM OUTER SPEAKER
- CHECK IF CABLES OF OUTER SPEAKER ARE CONNECTED CORRECTLY.