Mechanical Adjustments; Electrical Adjustments - Sony WM-EX402 Service Manual

SECTION 3

MECHANICAL ADJUSTMENTS

PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
playback head
capstan
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
pinch roller
rubber belt
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)
SECTION 4

ELECTRICAL ADJUSTMENTS

• Supplied voltage : 2.5 V
• Switches and control position
TAPE switch : NORM
GROOVE/MEGA BASS/
NORMAL switch : NORMAL (EX402/EX404)
SOUND switch : NORMAL (EX405/EX406)
VOL control : maximum
AVLS switch : NORM
DOLBY NR switch : OFF (Except EX402)
Test Tape
Type Signal
WS-48A 3 kHz, 0 dB
Tape Speed Adjustment
Procedure :
test tape
WS-48A
(3 kHz, 0 dB)
set
1. Playback WS-48A (tape center part) in the REV state and
adjust RV601 so that the frequency counter reading becomes
3,000 Hz.
2. Playback WS-48A (tape center part) in the FWD state.
Check that frequency counter reading is within ± 1.5% of the
reading of step 1.
Adjustment Location :
RV601
– 8 –
PRECAUTION
Used for
Tape Speed Adjustment
frequency counter
16 Ω
2
jack