Adjustments - Sony CRF-230B Service Manual

CRF-230B
SECTION 3
CIRCUIT ADJUSTMENTS
3-1. PREPARATION
1. Power Supply
At circuit adjustment remove the cabinet and
front panel, and supply dc 9V across the red
and the black lead wires shown in Fig. 3-1.
2. Receiver Control Setting
Set control knobs as follows except noted in
each adjustment.
* VOLUME Control Maximum
* BASS Control FLAT
* TREBLE Control FLAT
*« SENSITIVITY Dx
x SELECTIVITY SHARP
* ANL OFF
* BFO OFF
* AFC OFF
* MUTING OFF
3. Test Equipment/Tools Required
Rf Signal Generator
10.7 MHz Sweep/Marker Generator
Loop Antenna
Oscilloscope
VTVM
0.01 uF ceramic capacitor
40. Resistor
Screwdriver For Alignment
* *© &£ & & & &
pvc wire
3-2. AM IF ALIGNMENT
Preparation:
Band Selector: MW
Rf Signal Generator Coupling:
Loop antenna (See Fig. 3-2)
Modulation:
1-kHz 30% amplitude-modulated signal
VTVM Connection:
To EXT SP jack in parallel with 42 resistor
rf signal loop antenna
Fig. 3-2 A-mi-f alignment setup
test set
CRF-230B
4Q resistor
Rf Signal
Generator Adjust Remarks |
Frequency
455 kHz IFT 401 Adjust for maximum
IFT 501 meter reading on
IFT 502 VTVM.
IFT 504
Note: IFT401 is on the cp circuit board.
See Fig. 3-13 on page 25.
3-3. SSB DETECTOR ADJUSTMENT
Preparation:
Band Selector: MW
SELECTIVITY switch: SHARP
BFO Switch: ON
BFO Knob: Mechanical mid position
Rf Signal Generator Coupling: Loop antema
Setup: See Fig. 3-3.
Note: Be sure that a-m i-f section is aligned
for the normal operating condition
before adjusting ssb detector.
rf signal loop antenna
generator
a test set
oO CRF-230B8
Fig. 3-3 Ssb detector adjustment setup
Rf Signal
Adjust Remarks
Generator
Frequency
455 kHz BFO osc coil | Adjust for zero beat
unmodu- LT 801 hearing
lated
signal
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