Mechanical Adjustments; Electrical Adjustments - Sony PMC-222V Service Manual

SECTION 3

MECHANICAL ADJUSTMENTS

PRECAUTION
1. Clean the following parts with a denatured-alchool-moistened
swab:
record/playback head
erase head
capstans
2. Demagnetize the record/playback head with a head
demagnetizer. (Do not bring the head demagnetizer close to the
erase head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Torque Measurement
Mode Torque Meter
FWD
CQ-102C
FWD
back tension
Fast Forward
CQ-201B
Rewind
Tape Tension Measurement
MODE Torque Meter
FWD CQ-403A
pinch roller
rubber belts
Meter Reading
30 – 80g•cm
(0.42 – 1.12 oz•inch)
1.5 – 5.5g•cm
(0.021 – 0.07 oz•inch)
50 – 130g•cm
(0.77 – 1.80 oz•inch)
50 – 130g•cm
(0.77 – 1.80 oz•inch)
Meter Reading
more than 100g
(more than 3.53 oz)
— 21 —
SECTION 4

ELECTRICAL ADJUSTMENTS

TAPE RECODER SECTION
1. The sdjustments should be perfomed in the order given in the
service manual. (As a general rule. Playback circuit adjustment
should be completed before performing recording circuit
adjustment.)
2. The adjustments should be performed for both L-ch and R-ch
unless otherwise indicated.
Standard output level
Output Pin
Load impedance
Output signal level 0.775 V (0dB)
Test tape
Test Tape Signal
WS-48A 3kHz, 0dB
P-4-A063 6.3kHz, –10dB
Tape Speed Adjustment
Procedure :
Mode : Playback
test tape
WS-48A
(3kHz, 0dB)
set
Adjustment Value : normal tape speed
Speed checker
–1.0 to 1.0%
Frequency difference between the beginning and the end of the tape
should be within 1% (30Hz).
Adjustment Location :
1dB = 0.775V
SP OUT HP OUT
6 Ω 32 Ω
0.25 V (–10dB)
Used for
Tape speed adjustment
Head azimuth adjustment.
digital frequency
counter
32 Ω
+
–
J303 (phones)
Digital frequency counter
2,970 – 3,030Hz