Mechanical Adjustments; Electrical Adjustments - Sony WM-EX372 Service Manual

SECTION 3

MECHANICAL ADJUSTMENTS

3-1. MECHANICAL ADJUSTMENTS
Precaution
1. Clean the following parts with a denatured-alcohol-moistened
swab:
playback head pinch roller
capstan rubber belt
2. Demagnetize the 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 (2.5 V) unless otherwise noted.
Torque Measurement
Mode
Torque meter
FWD
CQ-102C
FWD
Back Tension
REV
CQ-102RC
REV
Back Tension
FF, REW CQ-201B
Tape Pulling Force Measurement
Mode Torque meter
FWD CQ-403A
REV CQ-403R
Meter reading
20 – 42 g•cm
(0.28 – 0.58 oz•inch)
less than 2 g•cm
(less than 0.03 oz•inch)
20 – 42 g•cm
(0.28 – 0.58 oz•inch)
less than 2 g•cm
(less than 0.03 oz•inch)
more than 50 g•cm
(more than 0.69 oz•inch)
Meter reading
more than 30 g
(more than 0.41 oz)
– 8 –
SECTION 4

ELECTRICAL ADJUSTMENTS

Precaution
• Supplied voltage: 2.5 V
• Switch and control position
NORM CrO /METAL switch: NORM
2
VOLUME CONTROL: maximum
TONE CONTROL HIGH and LOW: mechanical center
AVLS switch: NORM
MEGA BASS switch: OFF
DOLBY NR switch: OFF
Test tape
Type Signal
WS-48A 3 kHz, 0 dB
0 dB = 0.775 V
Tape Speed Adjustment
Procedure:
test tape
WS-48A
(3 kHz, 0 dB)
set
1. Playback WS-48A (tape end part) in the REV mode and adjust
RV601 so that the frequency counter reading becomes 2,980
Hz ± 1%.
2. Playback WS-48A (tape top part) in the FWD mode and check
that the frequency counter reading becomes 2,980 ± 45 Hz.
3. Playback WS-48A (tape end part) in the FWD mode and check
that the frequency counter reading recomes 2,980 ± 45 Hz.
4. Playback WS-48A (tape top part) in the REV mode and check
that the frequency counter reading becomes 2,980 ± 45 Hz.
Adjustment Location:
RV601
Used for
Tape Speed Adjustment
frequency counter
16 Ω
+
–
2
jack
label (model)