Sony HCD-VX777 Service Manual page 15

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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.
L-CH
peak
Output
level
R-CH
peak
Screw
position
3. Mode: Playback
test tape
P-4-A100
(10 kHz, –10 dB)
L-CH
MAIN
board
CN301
set
R-CH
TE
L 13942296513
in phase 45 °
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Playback Head (Deck A).
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.
forward
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within
1dB
within
1dB
L-CH R-CH
peak peak
oscilloscope
pin 3
pin 2
L
V H
R
pin 1
waveform of oscilloscope
90 ° 135 ° 180 °
good wrong
Record/Playback/Erase Head (Deck B).
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i
reverse
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8
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
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
Screw
test tape
position
WS-48B
(3 kHz, 0 dB)
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.
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3 6 7 1 3
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)
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
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.
2 9 9 4 2 8
DECK B
button.
frequency counter
+
set
–
main board
CN301 (Pin 3
(Pin 1
1 5 0 5 8 2 9 9 4
DECK A
level meter
set
main board
CN301 (Pin 3 : L-CH)
(WS-48B)
m
co
HCD-VX777
9 9
: L-CH)
: R-CH)
2 8 9 9
DECK B
+
–
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