Mechanical Adjustment; Electrical Adjustment - Sony WM-FS421 Service Manual

SECTION 4

MECHANICAL ADJUSTMENT

PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab:
playback head
rubber belts
2. Do not use a magnetized screwdriver for the adjustments.
Torque Measurement
Mode Torque Meter
FWD CQ-102C
FWD
CQ-102C
Back Tension
FF, REW CQ-201B
pinch roller
capstan
Meter Reading
2.0 to 4.1 N•m
(20 to 42 g•cm)
(0.27 to 0.58 oz•inch)
More tham 0.20 N•m
(More than 2.0 g•cm)
(More than 0.027 oz•inch)
More tham 4.9 N•m
(More than 50 g•cm)
(More than 0.69 oz•inch)
SECTION 5

ELECTRICAL ADJUSTMENT

TAPE SECTION
Test Tape
Tape Signal
WS-48A 3 kHz, 0 dB
Tape Speed Adjustment
Procedure:
Mode: Playback
Test tape
WS-48A
(3 kHz, 0 dB)
Set
Adjustment Value: normal tape speed
Adjust the tape speed adjustment RV601, so that the freqency counter
reading becomes 3,000Hz.
Specification Value:
Digital frequency counter
2,970 to 3,030 Hz
Frequency difference between the beginning and the end of the tape
should be within 1.5 % (45 Hz).
Adjustment Location:
WM-FS421
0 dB = 0.775 V
Used for
Tape speed adjustment
digital frequency
counter
16 Ω
+
–
J301 ( i )
RV601
7