Mechanical Adjustments; Electrical Adjustments - Sony PMC-DR50 Service Manual

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4-1. MECHANICAL ADJUSTMENTS

TAPE RECORDER SECTION
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback/erase head
rubber belts
2. Demagnetize the record/playback/erase head with a head demag-
netizer.
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 sup-
ply voltage unless otherwise noted.
Torque Measurement
Torque Torque Meter
Forward CQ-102C
Forward
CQ-102C
Back Tension
Reverse CQ-102RC
Reverse
CQ-102RC
Back Tension
FF/REW CQ-201B
TE
L 13942296513
Tape Tension Measurement
Mode Tension Meter
FWD CQ-403A
REV CQ-403A

4-2. ELECTRICAL ADJUSTMENTS

TAPE RECORDER SECTION
1. The adjustnemts should be performed in the order in the service
manual. (As a general rule playback circuit adjustment should
be completed beforeming recording circuit adjustment.)
2. The adjustments should be performed for bothe L-CH and R-
CH unless otherwise indicated.
Standard Intput Level
Input terminal
source impedance
input signal level
Standard Output Level
Output terminal
www
load impedance
output signal level
Test Tape
.
Type Signal
P-4-A100 10kHz, –10dB
WS-48B 3kHz, 0dB
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SECTION 4
ADJUSTMENTS
pinch roller
capstan
Meter Reading
36 to 61 g • cm
(0.5 to 0.84 oz • inch)
2 to 6 g • cm
(0.028 to 0.083 oz • inch)
36 to 61 g • cm
(0.5 to 0.84 oz • inch)
2 to 6 g • cm
(0.028 to 0.083 oz • inch)
61 to 143 g • cm
(0.85 to 1.98 oz • inch)
Meter Reading
more than 100g
(more than 3.53 oz)
more than 100g
(more than 3.53 oz)
0dB = 0.775V
LINE IN
10kΩ
0.5V (–3.8dB)
LINE OUT
47kΩ
0.5V (–3.8dB)
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Used for
Azimuth Adjustment
Tape Speed Adjustment
– 16 –
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2 9
8
Record/Playback/Erase Head Azimuth Adjustment
Procedure :
1. Mode : FWD playback
test tape
P-4-A100
(10kHz, –10dB)
set
2. Turn the adjustment screw for the maximum output levels. If
these levels do not match, turn the adjustment screw until both
of output levels match together within 1dB.
L-CH
peak
within
output
1 dB
level
R-CH
peak
Screw
position
Q Q
3 6 7 1 3 1 5
3. Phase Check
Mode : FWD playback
test tape
P-4-A100
(10kHz, –10dB)
L-CH
set
R-CH
in phase 45°
good
4. Change the reverse playback mode and repeat the step 1 to 3.
5. After the adjustment, lock the adjustment screw with suitable
locking compound.
Adjustment Location : – record/playback/erase head –
co
.
FWD side
adjustment screw
9 4 2 8
level meter
47K Ω
LINE OUT (JK301)
within
1 dB
screw position
L-CH R-CH
peak
peak
0 5 8 2 9 9 4 2 8
Osilloscope
47K Ω
V H
47K Ω
LINE OUT (JK301)
screen pattern
90° 135° 180°
wrong
m
REV side
9 9
9 9