Sony HCD-D890AV Service Manual page 13

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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 1 dB of peak.
L-CH
output
peak
level
R-CH
peak
screw
position
3. Mode: Playback
test tape
P-4-A100
(10kHz, –10dB)
TE
L 13942296513
in phase
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Adjustment Location: Playback Head (Deck A)
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within
1 dB
L-CH R-CH
peak peak
main board
CN403
Pin 3 (L-CH)
oscilloscope
Pin 2 (GND)
L
set
R
Pin 1 (R-CH)
Waveform of oscilloscope
45 ° 90 ° 135 ° 180 °
wrong
good
Record/Playback/Erase Head (Deck B)
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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 or normal
speed each time the H SPEED DUB. button is pressed.
Procedure :
With the power turned ON, press the SPECTRUM ANALYZER
button, ENTER button, and EFFECT button simultaneously.
within 1dB (The "VOLUME" on the fluorescent display tube will blink while
in the test mode.)
To exit the test mode, press the 1/u button.
1. Load WS-48B into deck B.
2. Play deck B.
3. Press the H SPEED DUB. button and play the tape at double
speed.
screw
position 4. Adjust RV652 of the AUDIO board so that the reading of the
frequency counter becomes 6000 ± 180 Hz.
5. Press the H SPEED DUB. button and play the tape at normal
speed.
6. Adjust RV651 of the AUDIO board so that the reading of the
frequency counter becomes 3000 ± 90 Hz.
Adjustment Location: AUDIO board
Sample Value of Wow and flutter
W.RMS (JIS) less than 0.3%
(test tape: WS-48B)
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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
reverse
co
.
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9 4 2 8
0 5 8 2 9 9 4 2 8
level meter
set
main board
Pin 3 (L-CH)
CN403
Pin 1 (R-CH)
m
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