HCD-GRX50, HCD-R770, HCD-RXD7, MHC-GRX50, MHC-R770, MHC-RXD7 - Sony Audio Service Manual (repair manual). Page 15

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Screw
position
L-CH
peak
within
1dB
Output
level
L-CH
peak
R-CH
peak
within
1dB
Screw
position
R-CH
peak
MAIN
board
CN301
set
test tape
P-4-A100
(10 kHz, –10 dB)
R-CH
oscilloscope
L-CH
R-CH
V
H
waveform of oscilloscope
in phase 45
°
90
°
135
°
180
°
good
wrong
main board
MD OUT jack (J101)
L-CH
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 1dB of peak.
3. Mode: Playback
4. Repeat step 1 to 3 in playback (REV) mode.
5. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
Tape Speed Adjustment
DECK B
Mode: Playback
1. Insert the WS-48B into the deck B.
2. Press the
( button on the deck B.
3. Press the 
[HI-DUB]
 button in playback mode.
Then at HIGH speed mode.
4. Adjust RV1001 on the LEAF SW board do that frequency
counter reads 6,000 ± 180 Hz.
5. Press the 
[HI-DUB]
 button.
Then back to NORMAL speed mode.
6. Adjust RV1002 on the LEAF SW board so that frequency
counter reads 3,000 ± 90 Hz.
Adjustment Location: LEAF SW board
Sample value of Wow and Flutter: 0.3% or less W.RMS (JIS)
(WS-48B)
Playback level Adjustment
DECK A      DECK B
Procedure:
Mode: Playback
Deck A is RV311 (L-CH) and RV411 (R-CH), Deck B is RV301
(L-CH) and RV401 (R-CH) so that adjustment within adjustment
level as follows.
Adjustment Level:
J101 PB level: 301.5 to 338.3 mV (–8.2 to –7.2 dB) level
difference between the channels: within ±0.5 dB
Adjustment Location: AUDIO board
forward
reverse
+
set
test tape
WS-48B 
(3 kHz, 0 dB)
main board
MD OUT jack (J101)
L-CH, R-CH
frequency counter
+
set
test tape
P-4-L300
(315 Hz, 0 dB)
main board
MD OUT jack (J101)
L-CH, R-CH
level meter
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