Read Sony CMT-EH20DAB / HCD-EH20DAB Service Manual online
10
HCD-EH20DAB
SECTION 5
MECHANICAL ADJUSTMENTS
SECTION 6
ELECTRICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback head
pinch roller
erase head
rubber belts
capstan
idlers
2. Demagnetize the record/playback head with a head
demagnetizer. (Do not bring the head magnetizer close to the
erase head.)
erase head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, appiy suitable locking compound to
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
Torque Meter
Meter Reading
2.0 – 8.0 mN
⋅
m
FWD
CQ-102AS
(20 – 80 g
⋅
cm)
(0.28 – 1.12 oz
⋅
inch)
FWD
0.15 – 0.6 mN
⋅
m
Back Tension
CQ-102C
(1.5 – 6.0 g
⋅
cm)
(0.021 – 0.083 oz
⋅
inch)
5.0 – 17.7 mN
⋅
m
FF
CQ-201AS
(50 – 177 g
⋅
cm)
(0.7 – 2.48 oz
⋅
inch)
5.0 – 17.7 mN
⋅
m
REW
CQ-201B
(50 – 177 g
⋅
cm)
(0.7 – 2.48 oz
⋅
inch)
TAPE TENSION MEASUREMENT
Mode
Tension Meter
Meter Reading
FWD
CQ-403A
more than 80 g
(more than 2.82 oz)
0 dB=0.775 V
DECK SECTION
1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
TEST TAPE
Tape
Signal
Used for
P-4-A063
6.3 kHz, -10 dB
Azimuth Adjustment
RECORD/PLAYBACK HEAD AZIMUTH ADJUSTMENT
Note:
Remove the sheet (azimuth) before this adjustment.
After the end of adjustment, try to paste sheet (azimuth) peeled off
to be the same position.
After the end of adjustment, try to paste sheet (azimuth) peeled off
to be the same position.
Procedure:
1. Mode: Playback
2. Turn the adjustment screw and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
so that outputs match within 1dB of peak.
3. Mode: Playback
set
test tape
P-4-A063
(6.3 kHz, –10 dB)
P-4-A063
(6.3 kHz, –10 dB)
oscilloscope
V
H
waveform of oscilloscope
in phase 45
°
90
°
135
°
180
°
good
wrong
MAIN board
PHONES jack
(J102)
PHONES jack
(J102)
Screw
position
position
L-CH
peak
peak
within
1dB
1dB
Output
level
level
L-CH
peak
peak
R-CH
peak
peak
within
1dB
1dB
Screw
position
position
R-CH
peak
peak
set
MAIN board
PHONES jack
(J102)
PHONES jack
(J102)
+
–
–
level meter
test tape
P-4-A063
(6.3 kHz, –10 dB)
P-4-A063
(6.3 kHz, –10 dB)
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