OK?..manual is complet and helpfull... for repairing such a old and rare boombox like JVC PCM it is necessary...
Text excerpt from page 12 (click to view)
SECTION 4 ELECTRICAL ADJUSTMENTS
BASE UNIT SECTION
Note: â¢ Apply 9V dc from regurated DC power supply. â¢ Perform the adjustment at T3CH (28CH : 49.910 MHz) as a rule. â¢ Set to base unit manual test mode. (Refer to page 7.) â¢ Switch position : S302 (DIAL MODE) : P (pulse) TX SECTION ADJUSTMENT â¢ The electrolytic capacitor (10 ÂµF/10 V) connected TP23 (DET OUT) to TP19 (GND). (Only TX section adjustment) TX VT Adjustment Setting :
TP2 TP3 (RX GND) Carrier frequency : 49.910 MHz Modulation Deviation Output level : 1 kHz : FM 3 kHz : 60 dBÂµV (1 mV) (EMF)
RX SECTION ADJUSTMENT RX LEVEL Adjustment Note: â¢ Perform the adjustment at T3CH (28CH : 49.910 MHz) as a rule. Setting :
FM RF signal generator
TP6 (TX VT) TP19 (GND)
Procedure : 1. The digital voltmeter connected TP6 (TX VT) to TP19 (GND). 2. Adjust the L52 for 2.2 Â± 0.05 V reading on the digital voltmeter. RX VT Adjustment Setting :
TP105 TP104 600 â¦
PBX tester or DC 48V F.B.
TP5 (RX VT) TP3 (RX GND)
Procedure : 1. Adjust the FL101 for the maximam reading on the level meter. Also check that the output level is the specified values. Specified Value : â1.4 to â9.6 dBV RSSI Hi Adjustment Note: â¢ Perform the adjustment at T3CH (28CH : 49.910 MHz) as a rule. Setting :
AF oscillator FM RF signal generator
Procedure : 1. The digital voltmeter connected TP5 (RX VT) to TP3 (RX GND). 2. Adjust the L101 for 2.4 Â± 0.05 V reading on the digital voltmeter.
Procedure : 1. Use the oscilloscope to confirm the FM RF signal generator input (AF) signal waveform and RSSI signal, and use the RV101 so that they are synchronized (duty is synchronized).
RSSI output waveform 0V Adjust so that they synchronize at 0 V. RSSI WAVEFORM AF oscillator EXT signal 20 Hz
Adjustment Location : base main board (See page 13.)