Sony HCD-D90AV Service Manual page 14

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
CN403
(10kHz, –10dB)
Pin 3 (L-CH)
L
set
R
Pin 1 (R-CH)
Waveform of oscilloscope
in phase 45˚
good
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Adjustment Location: Playback Head (Deck A)
Record/Playback/Erase Head (Deck B)
foward
within 1dB
screw
L-CH position
R-CH
peak
peak
oscilloscope
Pin 2 (GND)
135˚ 180˚
90˚
wrong
reverse
Tape Speed Adjustment (Deck A)
Note: Set the test mode using the following method and begin tape
speed adjustment.
In the test mode, the tape will move at double speed while
the HIGH SPEED DUBBING button is pressed.
Procedure:
With the power turned ON, press the SPECTRUM ANALYZER
button, ENTER/NEXT button, and EFFECT ON/OFF button
simultaneously.
(The "VOLUME" on the fluorescent display tube will blink while
in the test mode.)
To exit the test mode, press the POWER button.
1. Load WS-48B into deck A and a recordable tape into deck B.
2. Press the r REC button, and press the · button of deck B to
set deck B into the recording state.
3. Play deck A.
4. While pressing the HIGH SPEED DUBBING button, set double
speed play.
5. Adjust RV652 of the AUDIO board so that the reading of the
frequency counter becomes 6000 ± 30 Hz.
6. Release the HIGH SPEED DUBBING button to set normal
speed play.
7. Adjust RV651 of the AUDIO board so that the reading of the
frequency counter becomes 3000 ± 15 Hz.
Adjustment Location: AUDIO board
Playback Level Adjustment (Deck A, Deck B)
Procedure:
Mode: Playback
test tape P-4-L300
(315Hz, 0dB)
Deck A is RV311 (L-CH) and RV411 (R-CH), deck B is RV301
(L-CH) and RV401 (R-CH)
so that adjustment within the following adjustment level.
Adjustment level:
CN403 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: AUDIO board
— 14 —
level meter
set
main board
CN403 Pin 3 (L-CH)
Pin 1 (R-CH)