Sony HCD-VX777 Service Manual page 15

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.
within
L-CH
1dB
peak
Output
level
R-CH
peak
Screw
position
L-CH
peak
3. Mode: Playback
test tape
P-4-A100
(10 kHz, –10 dB)
pin 3
L-CH
MAIN
L
board
CN301
R
set
R-CH
pin 1
waveform of oscilloscope
in phase 45
good
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
forward
reverse
within
1dB
Screw
position
R-CH
peak
oscilloscope
pin 2
V H
90 135 180
wrong
Tape Speed Adjustment
Note: Start the Tape Speed adjustment as below after setting to the test
mode.
In the test mode, the tape speed is high during pressing the
CD SYNC HI-DUB
button.
Procedure:
1. Turn the power switch on.
2. Press the x button, ENTER button and DISC 3 button
simultaneously.
(The "TEST MODE" on the fluorescent indicator tube display
while in the test mode.)
To exit from the test mode, press the ?/1 button.
Mode: Playback
test tape
WS-48B
(3 kHz, 0 dB)
set
main board
CN301 (Pin 3
1. Insert the WS-48B into the deck B.
2. Press the gG button on the deck B.
3. Press the CD SYNC 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 ± 30 Hz.
5. Press the CD SYNC HI-DUB button.
Then back to NORMAL speed mode.
6. Adjust RV1002 on the LEAF SW board so that frequency
counter reads 3,000 ± 15 Hz.
Adjustment Location: LEAF SW board
Playback level Adjustment
Procedure:
Mode: Playback
test tape
P-4-L300J
(315 Hz, 0 dB)
set
main board
CN301 (Pin 3 : L-CH)
Deck A is RV302 (L-CH), Deck B is RV303 (L-CH) so that
adjustment within adjustment level as follows.
Adjustment Level:
CN301 PB level: 334.4 to 748.7 mV (–7.3 to –0.3 dB) level
difference between the channels: within ±0.5 dB
Adjustment Location: MAIN board
Sample Volue of Wow and Flutter: 0.3% or less W. RMS
HCD-VX777
DECK B
frequency counter
+
–
: L-CH)
(Pin 1 : R-CH)
DECK A DECK B
level meter
+
–
(WS-48B)
15