Mechanical Adjustments; Electrical Adjustments - Sony HCD-D90AV Service Manual

SECTION 5

MECHANICAL ADJUSTMENTS

Precaution
1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback heads
erase head
capstan
2. Demagnetize the record/playback head with a head demagne-
tizer.
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 sup-
ply voltage unless otherwise noted.
Torque Measurement
Torque meter
Torque
FWD CQ-102C
FWD
CQ-102C
back tension
REV CQ-102RC
REV
CQ-102RC
back tension
FF/REW CQ-201B
FWD tension CQ-403A
CQ-403R
REV tension
pinch rollers
rubber belts
idlers
Meter reading
36 to 61 g • cm
(0.5 - 0.84 oz • inch)
2 to 6 g • cm
(0.02 - 0.08 oz • inch)
36 to 61 g • cm
(0.5 - 0.84 oz • inch)
2 to 6 g • cm
(0.02 - 0.08 oz • inch)
61 to 143 g • cm
(0.85 - 1.99 oz • inch)
100 g or more
(3.53 oz or more)
100 g or more
(3.53 oz or more)
— 13 —
SECTION 6

ELECTRICAL ADJUSTMENTS

DECK SECTION 0 dB=0.775V
1. Demagnetize the record/playback head with a head damagnetizer.
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.
Tape Signal
P-4-A100
10 kHz, –10 dB
WS-48B 3 kHz, 0 dB
P-4-L300
315 Hz, 0 dB
Record/Playback Head Azimuth Adjustment
(Deck A, Deck B)
Note: Perform this adjustments for both decks.
Procedure:
1. Mode : Playback
test tape
P-4-A100 main board
(10kHz, –10dB)
CN403
Pin 3 (L-CH)
Pin 1 (R-CH)
set
main board
CN403
Pin 2 (GND)
Used for
Azimuth Adjustment
Tape Speed Adjustment
Level Adjustment
level meter
+
–