HCD-ZX70DVD - Sony Audio Service Manual (repair manual). Page 17

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17
5.
ELECTRICAL  ADJUSTMENTS
DECK SECTION
0 dB=0.775V
1. Demagnetize the record/playback head with a head demagne-
tizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
parts adjusted.
4. The adjustments should be performed with the rated power sup-
ply voltage unless otherwise noted.
5. The adjustments should be performed in the order given in this
service manual. (As a general rule, playback circuit adjustment
should be completed before performing recording circuit adjust-
ment.)
6. The adjustments should be performed for both L-CH and R-CH.
7. Switches and controls should be set as follows unless otherwise
specified.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Adjustment Location: Playback Head (Deck A)
Record/Playback/Erase Head (Deck B)
3. Mode: Playback
Test tape
P-4-A100
(10kHz, –10dB)
Oscilloscope
MAIN 
board 
CN301 
Set
Waveform of oscilloscope
in phase
45
°
90
°
135
°
180
°
Good
Wrong
2
1
3
L
R
R-CH
V
H
Reverse
Forward
Record/Playback Head Azimuth Adjustment
(Deck A, Deck B)
Note:
Perform this adjustments for both decks.
Procedure:
1. Mode : Playback
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.
Test tape
P-4-A100
(10kHz, –10dB)
MAIN board
CN301 
1
 (L-CH),
CN301 
3
 (R-ch)
Level meter
Set
+
MAIN board
CN301 
2
 (GND)
L-CH
peak
R-CH
peak
Screw
position
Output
level
Within
1 dB
L-CH
peak
R-CH
peak
Screw
position
Within 1dB
Signal
Used for
Tape
P-4-A100
WS-48B
P-4-L300
10 kHz, –10 dB
3 kHz, 0 dB
315 Hz, 0 dB
Azimuth Adjustment
Tape Speed Adjustment
Level Adjustment
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