Mechanical Adjustments; Electrical Adjustments Tape Section - Sony PHC-ZW770L Service Manual
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Also See for PHC-ZW770L:
- Operating instructions manual (72 pages) ,
- Service manual (10 pages) ,
- Service manual (10 pages)
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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 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.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
6. Power supply voltage: 9 V dc.
Torque Measurement DECK A
Mode
Torque meter
Forward
CQ-102C
Forward
CQ-102C
back tension
Fast Forward
and
CQ-201B
Rewind
Tape Tension Measurement DECK A
Mode
Tension meter
Forward
CQ-403A
pinch roller
rubber belts
idlers
DECK B
Meter reading
22.5 to 55 g • cm
(0.31 to 0.76 oz • inch)
2 to 5 g • cm
(0.03 to 0.07 oz • inch)
60 to 120 g • cm
(0.83 to 1.67 oz • inch)
DECK B
Meter reading
more than 150 g
(more than 5.29 oz)
ELECTRICAL ADJUSTMENTS
TAPE SECTION
Standard Output Level
Output terminal
load impedance
output signal level
Test Tape
Tape
WS-48A
3 kHz, 0 dB
Tape Speed Adjustment DECK A
Procedure:
• Perform normal speed adjustment before high speed check.
Mode: playback (deck A)
record (deck B)
test tape
WS-48A
(3 kHz, 0 dB)
set
Adjust RV301 so that reading on digital frequency counter
becomes 3,000 Hz.
Specification Value:
Tape
Deck
speed
A
Normal (playback)
A
HI-SPEED DUBBING
(playback)
B
HI-SPEED DUBBING
(record)
Frequency difference between the beginning and the end of the
tape should be within ± 1.5% (both Normal and Hi-speed).
Adjustment Location: – main board (component side) –
– 12 –
SECTION 4
0 dB = 0.775 V
SP OUT
PHONES OUT
6 Ω
0.775 V (0 dB)
0.25 V (–10 dB)
Signal
Used for
tape speed adjustment
DECK B
digital frequency
counter
0000
32 Ω
PHONES jack (J301)
Adjustment
Frequency
point
RV301
2,985 to 3,015 Hz
(confirmation) 5,700 to 6,500 Hz
———
32 Ω
counter
———
RV301
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