Read Sony HCD-ZX70DVD Service Manual online
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
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.)
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
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)
P-4-A100
(10kHz, –10dB)
Oscilloscope
MAIN
board
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)
(Deck A, Deck B)
Note:
Perform this adjustments for both decks.
Procedure:
1. Mode : Playback
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.
that outputs match within 1 dB of peak.
Test tape
P-4-A100
(10kHz, –10dB)
P-4-A100
(10kHz, –10dB)
MAIN board
CN301
CN301
1
(L-CH),
CN301
3
(R-ch)
Level meter
Set
+
–
MAIN board
CN301
CN301
2
(GND)
L-CH
peak
peak
R-CH
peak
peak
Screw
position
position
Output
level
level
Within
1 dB
1 dB
L-CH
peak
peak
R-CH
peak
peak
Screw
position
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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