Mechanical Adjustments; Electrical Adjustments - Sony HCD-EC70 Service Manual

MECHANICAL ADJUSTMENTS

• Precaution
1. Clean the following parts with a denatured-alcohol-moistened
swab :
2. Demagnetize the record/playback head with a head
demagnetizer. (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, appiy 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
FWD
FWD
back tension
FF
REW
• Tape Tension Measurement
Mode
FWD
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SECTION 4
record/playback head pinch roller
erase head rubber belts
capstan idlers
Torque meter
2.0 – 8.0 mN • m
CQ-102AS
(0.28 – 1.12 oz • inch)
0.15 – 0.6 mN • m
CQ-102C
(0.021 – 0.083 oz • inch)
CQ-201AS (50 to 177 g • cm)
(0.7 – 2.48 oz • inch)
CQ-201B (50 to 177 g • cm)
(0.7 – 2.48 oz • inch)
Tension Meter Meter Reading
CQ-403A
(more than 2.82 oz)
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DECK SECTION
1. Demagnetize the record/playback head with a head
2. Do not use a magnetized screwdriver for the adjustments.
• Test Tape
P-4-A063
RECORD/PLAYBACK HEAD AZIMUTH ADJUSTMENT
Procedure:
1. Mode: Playback
Meter reading
(20 to 80 g • cm)
(1.5 to 6 g • cm)
5 – 17.7 mN • m
5 – 17.7 mN • m
2. Turn the adjustment screw and check output peaks. If the peaks
more than 80 g
Screw
position
3. Mode: Playback
4. After the adjustments, apply suitable locking compound to
SECTION 5

ELECTRICAL ADJUSTMENTS

0 dB=0.775 V
demagnetizer.
Tape Signal
6.3 kHz, -10 dB
test tape
JACK board
P-4-A063
PHONES jack
(6.3 kHz, − 10 dB)
(J102)
set
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
within
L-CH
1dB
peak
Output
level
R-CH
peak
L-CH R-CH
peak peak
test tape
JACK board
P-4-A063
(6.3 kHz, − 10 dB)
PHONES jack
(J102)
set
waveform of oscilloscope
in phase 45 ° 90 ° 135 ° 180 °
good
the pats adjusted.
HCD-EC70
Used for
Azimuth Adjustment
level meter
+
–
within
1dB
Screw
position
oscilloscope
V H
wrong
17