Adjustments; Mechanical Adjustments; Electrical Adjustments - Sony Walkman WM-FX491 Service Manual

3-1. 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.
Do not use a magnetized screwdriver for the adjustments.
3. These measurement and adjustment 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
SECTION 3

ADJUSTMENTS

pinch roller
rubber belt
Meter reading
20 – 42 g • cm
(0.28 – 0.58 oz• inch)
less than 2 g • cm
(less than 0.027 oz• inch)
20 – 42 g • cm
(0.28 – 0.58 oz• inch)
less than 2 g • cm
(less than 0.027 oz• inch)
more than 60 g • cm
(more than 0.84 oz• inch)
– 8 –

3-2. ELECTRICAL ADJUSTMENTS

PRECAUTION
• Supplied voltage : 2.5V.
• Switch and control position
MEGA BASS : OFF
VOLUME control : maximum
AVLS : NORM
TAPE SECTION 0 dB = 0.775V
Test Tape
Type Signal
WS-48A 3kHz, 0dB
Tape Speed Adjustment
Procedure :
test tape
WS-48A
(3kHz, 0dB)
set
1. Playback WS-48A (tape center part) in the FWD state and ad-
just RV601 so that the frequency counter reading becomes
3,000Hz.
Standard value : 2,985–3,015Hz
2. Playback WS-48A (tape center part) in the REV state.
Check that frequency counter reading is within ±1.0% of the
reading of step 1.
Adjustment Location :
Used for
Tape Speed Adjustment
frequency counter
32 Ω
phones jack (J301)
RV601