Sony PMC-DR50L / PMC-DR70L Service Manual ▷ View online
– 17 –
3-22. POWER TRANSFOMER BOARD
3-23. SP MAIN BOARD, SP AMP IC BOARD
2
Cabinet, Wood
1
Screws (+P 4x10)
Power transformer board
Bracket, Transfomer
Bracket, Transfomer
SP main board
SP AMP IC board
Cover
1
Screws (+BVTT 3x12)
1
Screws (+BVTT 3x8)
1
Screw
Cabinet (L) bottom
– 18 –
3-24. AC OUTLET BOARD, SP JACK BOARD
5
4
2
1
Screws
(+BVTT 3x8)
3
Screws (+BVTT 3x8)
6
Screw (+BVTT 3x8)
Cabinet (L) bottom
AC outlet board
SP jack board
Board (L) back
Stopper, cord
Airtight clipper
Bracket
Cord, AC
3-25. CABINET (SWF) BOTTOM, CONNECTOR BOARD
< SUPER WOOFER UNIT > (DR70L)
4
1
Screws (+P 4x16)
3
Screws (+BVTT 3x8)
Cabinet (SWF) wood
Cabinet (SWF) bottom
2
Screws
(+P 4x16)
6
Connector board
5
Screws (+BVTT 3x8)
– 19 –
3-26. SPEAKER (SP601), “CABINET, FRONT”
3-27. LED BOARD, VOLUME BOARD
2
5
Speaker (SP601)
1
Screws (+P 4x16)
4
Screws (+P 4x16)
4
Screws (+P 4x16)
3
Pull up a airtight
clipper.
Cabinet (SWF) wood
Cabinet, front
5
7
6
Screws (+BVTT 3x8)
3
Nut and waher
2
4
Screws (+PWH 3x10)
1
Hang thread in a circumuference of
“Knob ASSY, VOL”, and pull it up
LED board
Cabinet, front
Chassis (SWF) sub
Knob ASSY, VOL
Thread
Volume board
– 20 –
4-1. MECHANICAL ADJUSTMENTS
TAPE RECORDER SECTION
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback/erase head
pinch roller
rubber belts
capstan
2. Demagnetize the record/playback head with a head demagne-
tizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
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
Meter Reading
3.54 to 5.98 mN • m
Forward
CQ-102C
(36 to 61 g • cm)
(0.5 to 0.84 oz • inch)
Forward
0.197 to 0.588 mN • m
Back Tension
CQ-102C
(2 to 6 g • cm)
(0.028 to 0.083 oz • inch)
3.54 to 5.98 mN • m
Reverse
CQ-102RC
(36 to 61 g • cm)
(0.5 to 0.84 oz • inch)
Reverse
0.197 to 0.588 mN • m
Back Tension
CQ-102RC
(2 to 6 g • cm)
(0.028 to 0.083 oz • inch)
5.99 to 14.02 mN • m
FF/REW
CQ-201B
(61 to 143 g • cm)
(0.85 to 1.98 oz • inch)
Tape Tension Measurement
Mode
Tension Meter
Meter Reading
FWD
CQ-403A
more than 100g
(more than 3.53 oz)
REV
CQ-403A
more than 100g
(more than 3.53 oz)
SECTION 4
ADJUSTMENTS
4-2. ELECTRICAL ADJUSTMENTS
TAPE RECORDER SECTION
0dB = 0.775V
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.)
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
LINE IN
source impedance
10k
Ω
input signal level
0.5V (–3.8dB)
Record/Playback/Erase Head Azimuth Adjustment
Procedure :
1. Mode : FWD playback
1. Mode : FWD playback
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.
of output levels match together within 1dB.
3. Phase Check
Mode : FWD playback
set
LINE OUT (JK301)
47k
Ω
level meter
test tape
P-4-A100
(10kHz, –10dB)
P-4-A100
(10kHz, –10dB)
L-CH
peak
peak
R-CH
peak
peak
L-CH
peak
peak
R-CH
peak
peak
Screw
position
position
output
level
level
within
1 dB
within
1 dB
screw position
V
H
in phase
90
°
45
°
135
°
180
°
good
wrong
set
L-CH
R-CH
screen pattern
test tape
P-4-A100
(10kHz, –10dB)
P-4-A100
(10kHz, –10dB)
Osilloscope
LINE OUT (JK301)
47k
Ω
47k
Ω
Standard Output Level
Output terminal
LINE OUT
load impedance
47k
Ω
output signal level
0.5V (–3.8dB)
Test Tape
Type
Signal
Used for
P-4-A100
10kHz, –10dB
Azimuth Adjustment
WS-48B
3kHz,
0dB
Tape Speed Adjustment
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