Sony HCD-GNZ55D Service Manual page 25

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DECK SECTION
1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
parts adjust.
4. The adjustments should be performed with the rated power
supply 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
adjustment.)
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.
• Test Tape
Tape
P-4-A063 6.3 kHz, –10 dB
Record/Playback Head Azimuth Adjustment
DECK A DECK B
Note: Perform this adjustments for both decks
Procedure:
1. Mode: Playback
test tape
TE P-4-A063
L 13942296513
(6.3 kHz, –10 dB)
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
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0 dB=0.775 V
Signal Used for
Azimuth Adjustment
MAIN board
IC101
Pin 28 (L-CH)
level meter
Pin 37 (R-CH)
set
+
–
MAIN board
IC101
Pin 36 (GND)
within
1dB
within
1dB
L-CH
R-CH
peak peak
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2 9
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3. Mode: Playback
test tape
P-4-A063
(6.3 kHz, –10 dB)
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Playback Head (Deck A).
Q Q
3 6 7 1 3
forward
screw
position
.
HCD-GNZ55D
9 4 2 8
oscilloscope
pin 28
L-CH
pin 36
L
MAIN
V
board
IC101 R
R-CH
pin 37
waveform of oscilloscope
in phase 45 ° 90 ° 135 ° 180 °
good wrong
Record/Playback/Erase Head (Deck B).
1 5 0 5 8 2 9 9 4
reverse
m
co
9 9
H
2 8 9 9
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