Mechanical Adjustments; Tel 13942296513; Electrical Adjustments Deck Section - Sony HCD-GN77D Service Manual

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3 7 63 1515 0

MECHANICAL ADJUSTMENTS

Precaution
1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback heads
erase head rubber belts
capstan idlers
2. Demagnetize the record/playback head with a head
demagnetizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
Torque Measurement
Mode
FWD
FWD
back tension
REV
REV
back tension
TE
L 13942296513
FF/REW
FWD tension
REV tension
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SECTION 5
pinch rollers
Torque meter Meter reading
3.06 N • m to 6.96 N • m
31 to 71 g • cm
CQ-102C
(0.43 – 0.98 oz • inch)
0.19 N • m to 0.58 N • m
CQ-102C 2 to 6 g • cm
(0.02 – 0.08 oz • inch)
3.06 N • m to 6.96 N • m
CQ-102RC 31 to 71 g • cm
(0.43 – 0.98 oz • inch)
0.19 N • m to 0.58 N • m
CQ-102RC 2 to 6 g • cm
(0.02 – 0.08 oz • inch)
6.96 N • m to 14.02 N • m
CQ-201B 71 to 143 g • cm
(0.98 – 1.99 oz • inch)
9.80 N • m
CQ-403A 100 g or more
(3.53 oz or more)
9.80 N • m
CQ-403R 100 g or more
(3.53 oz or more)
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8
ELECTRICAL ADJUSTMENTS
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-A100
WS-48B
RECORD/PLAYBACK HEAD AZIMUTH ADJUST-
MENT
DECK A
Note: Perform this adjustments for both decks
Q Q
Procedure:
3 6 7 1 3
1. Mode: Playback
test tape
P-4-A100
(10 kHz, –10 dB)
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SECTION 6
2 9 9 4 2 8
0 dB=0.775 V
Signal
10 kHz, –10 dB Azimuth Adjustment
3kHz, 0dB Tape Speed Adjustment
DECK B
1 5 0 5 8 2 9 9 4
MAIN board
CN301
Pin 1 (L-CH)
Pin 3 (R-CH)
set
MAIN board
CN301
Pin 2 (GND)
m
co
HCD-GN77D
9 9
Used for
2 8 9 9
level meter
+
–
19