Read Sony HCD-EC68W / MHC-EC68W Service Manual online
HCD-EC68W
18
SECTION 5
MECHANICAL ADJUSTMENTS
SECTION 6
ELECTRICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
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 demag-
netizer. (Do not bring the head magnetizer close to the erase
head.)
head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, appiy suitable locking compound to the
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
FWD
CQ-102AS
2.0 – 8.0 mN • m
(20 to 80 g • cm)
(0.28 – 1.12 oz • inch)
FWD
Back Tension
Back Tension
CQ-102C
0.15 – 0.6 mN • m
(1.5 to 6 g • cm)
(0.021 – 0.083 oz • inch)
FF
CQ-201AS
5 – 17.7 mN • m
(50 to 177 g • cm)
(0.7 – 2.48 oz • inch)
REV
CQ-201B
5 – 17.7 mN • m
(50 to 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)
1. Demagnetize the record/playback head with a head demagne-
tizer.
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: Perform this adjustments for both decks.
Procedure:
1. Mode:
1. Mode:
Playback
set
JACK board
PHONES jack
(J492)
PHONES jack
(J492)
+
–
level meter
test tape
P-4-A063
(6.3 kHz,
P-4-A063
(6.3 kHz,
−10 dB)
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)
oscilloscope
V
H
waveform of oscilloscope
in phase 45
°
90
° 135° 180°
good
wrong
JACK board
PHONES jack
(J492)
PHONES jack
(J492)
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Screw
position
L-CH
peak
within
1 dB
Output
level
L-CH
peak
R-CH
peak
within
1 dB
Screw
position
R-CH
peak
DECK SECTION
0 dB = 0.775V
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