Sony HCD-GR3 Service Manual page 11

2. Turn the adjustment screw and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw so
that outputs match within 1 dB of peak.
L-CH
peak
output
within
level
1dB
R-CH
peak
screw
position
3. Mode : Playback
test tape
main board
P-4-A100
CN307
(10kHz, –10dB)
Pin 1 (L-CH)
set
Pin 3 (R-CH)
Waveform of oscilloscope
in phase 45˚
good
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Adjustment Location :
Adjustment screws
REC/PB head (deck B)
or PB hear (deck A)
within 1dB
screw
L-CH R-CH
position
peak
peak
oscilloscope
Pin 2 (GND)
L
R
135˚ 180˚
90˚
wrong
Tape Speed Adjustment (Deck A, Deck B)
Procedure :
Mode : Playback
test tape
WS-48B
(3kHz, 0dB)
set
1. Insert the WS-48B into the deck B, and playback.
2. Adjust the RV380 so that the frequency counter reading becomes
3000 ± 10 Hz.
3. Stop the deck B. Insert the WS-48B into the deck A to playback.
Be sure to check that the difference of the frequency compared
with the deck B becomes within +2% and –0.5%.
4. Insert the CS-123 (blank tape) into the deck A and insert the
WS-48B into the deck B, then playback them simultaneously.
Be sure to check that the deck B's frequency counter reading
becomes 3000 ± 50 Hz.
Adjustment Location : MAIN board
Playback Level Adjustment (Deck A, Deck B)
Procedure :
Mode : Playback
test tape
P-4-L300
(315Hz, 0dB)
set
Deck A is RV301 (L-CH) and RV401 (R-CH),
Deck B is RV302 (L-CH) and RV402 (R-CH)
so that adjustment within the following adjustment level.
Adjustment level :
CN307 playback level: 301.5 to 338.3 mV (–8.2 to –7.2 dB)
level difference between the channels: within ±0.5 dB
Adjustment Location : MAIN board
— 11 —
frequency counter
+
–
main board
CN307 Pin 1 (L-CH)
Pin 3 (R-CH)
level meter
main board
CN307 Pin 1 (L-CH)
Pin 3 (R-CH)