Mechanical Adjustments; Electrical Adjustments Tape Section - Sony PMC-107L Service Manual

SECTION 3

MECHANICAL ADJUSTMENTS

PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback head
erase head
capstan
2. Demagnetize the record/playback head with a head demagne-
tizer. (Do not bring the head magnetizer 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.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
Torque Measurement
Mode Torque meter
FWD CQ-102C
FWD
CQ-102C
Back Tension
FF CQ-201B
REW CQ-201B
Tape Tension Measurement
Mode Tension meter
FWD CQ-403A
pinch roller
rubber belts
idlers
Meter reading
30 – 70 g • cm
(0.42 – 0.97 oz • inch)
1.5 – 5.5 g • cm
(0.021 – 0.076 oz • inch)
more than 60 g • cm
(more than 0.83 oz • inch)
more than 60 g • cm
(more than 0.83 oz • inch)
Meter Reading
more than 100 g
(more than 3.53 oz)
ELECTRICAL ADJUSTMENTS
TAPE SECTION
• Standard Output Level
Output terminal
load impedance
output signal level
• Test Tape
Type
WS-48A 3 kHz, 0 dB
Tape Speed Adjustment
Procedure:
Mode: playback
test tape
WS-48A
(3 kHz, 0 dB)
set
1. Make sure that the value indicated on the frequency counter
falls into the specification.
2. If out of specification, adjust so that the value on the frequency
counter is 3 kHz.
Adjustment Value:
Digital frequency counter
2,985 to 3,015 Hz
Adjust so that the frequency at the beginning and that at the end of
tape winding are between 2,955 to 3,045 Hz.
Adjustment Location:
– 13 –
SECTION 4
0 dB = 0.775 V
HP OUT
32 Ω
0.25 V (–10 dB)
Signal Used for
tape speed adjustment
digital frequency
counter
32 Ω
phones jack
TAPE SPEED
Adjustment