Read Sony BM-575 / BM-577 (serv.man3) Service Manual online
2
BM-575/577
1. MECHANICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured alcohol moistened
swab:
record/playback/erase head
record/playback/erase head
pinch roller
rubber belts
capstan idlers
2. Demagnetize the record/playback/erase head with a head
demagnetizer.
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
supply voltage (dc 2.5 V) unless otherwise noted.
• Switches and control should be set as follows unless otherwise
specified.
MIC SENS selector
: CONF
TAPE SPEED selector : 2.4 cm
FAST PB switch
FAST PB switch
: OFF
VOR switch
: OFF
VOL control
: mechanical center
Torque Measurement
Mode
Torque meter
Meter reading
(Cassette type)
LISTEN
CQ-103M
5 to 12 g•cm
(0.069 to 0.167 oz•inch)
FF/CUE
CQ-201M
more than 5 g•cm
(more than 0.069 oz•inch)
B. SPACE
CQ-201M
more than 14 g•cm
(more than 0.194 oz•inch)
Tape Tension Measurement
Mode
Tension meter
Meter reading
(Cassette type)
LISTEN
CQ-403M
25 to 55 g
(0.88 to 1.94 oz)
Timing Adjustment
1. Take-up reel spindle should rotate at the same time as pinch
roller or earlier than pinch roller in STOP to LISTEN/DICT
mode.
Confirm that the pinch roller presses to capstan and they rotate.
mode.
Confirm that the pinch roller presses to capstan and they rotate.
2. When they are not correctly rotate, adjust the place of adjustment
plate so that it is wide.
2. ELECTRICAL ADJUSTMENTS
PRECAUTION
1. Demagnetize the record/playback/erase head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
3. After the adjustments, apply suitable locking compound to the
parts adjusted.
4. The adjustments should be performed with the rated power
supply voltage (dc 2.5 V) unless otherwise noted.
5. The adjustments should be performed in the order given in this
service manual. (As a general rule, playback circuit adjustment
should be completed before performing recording circuit
adjustment.)
should be completed before performing recording circuit
adjustment.)
• Switches and control should be set as follows unless otherwise
specified.
MIC SENS selector
: CONF
TAPE SPEED selector : 2.4 cm
FAST PB switch
FAST PB switch
: OFF
VOR switch
: OFF
VOL control
: mechanical center
Test Tape
Type
Signal
Used for
WS-24
3 kHz, –10 dB
Tape Speed (2.4 cm) Adjustment
WS-12
3 kHz, –10 dB
Tape Speed (1.2 cm) Adjustment
S-2-A030A 3 kHz, –20 dB
Head Azimuth Adjustment
Tape Speed (2.4 cm) Adjustment
Setting:
TAPE SPEED selector: 2.4 cm
Procedure:
1. Mode: LISTEN
1. Mode: LISTEN
FWD idler
adjustment plate
screw fixing the
adjustment plate
adjustment plate
0.3 to 0.6mm
2. Adjust VR102 so that the frequency counter reads 2,990 to 3,010
Hz.
Adjustment Location: See page 3.
Tape Speed (1.2 cm) Adjustment
Setting:
TAPE SPEED selector: 1.2 cm
Procedure:
1. Mode: LISTEN
1. Mode: LISTEN
2. Adjust VR103 so that the frequency counter reads 2,990 to 3,010
Hz.
Adjustment Location: See page 3.
set
test tape
WS-24
(3 kHz,
WS-24
(3 kHz,
−
10 dB)
frequency counter
EAR jack
set
test tape
WS-12
(3 kHz,
WS-12
(3 kHz,
−
10 dB)
frequency counter
EAR jack
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