Read Sony CMT-NEZ7DAB / HCD-NEZ7 Service Manual online
HCD-NEZ7
13
13
HCD-NEZ7
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
2.95 – 6.86 mN
⋅
m
FWD
CQ-102C
(30 – 70 g
⋅
cm)
(0.42 – 0.97 oz
⋅
inch)
FWD
0.15 – 5.39 mN
⋅
m
Back Tension
CQ-102C
(1.5 – 5.5 g
⋅
cm)
(0.021 – 0.076 oz
⋅
inch)
more than 5.89 mN
⋅
m
FF
CQ-201B
(more than 60 g
⋅
cm)
(more than 0.83 oz
⋅
inch)
more than 5.89 mN
⋅
m
REW
CQ-201B
(more than 60 g
⋅
cm)
(more than 0.83 oz
⋅
inch)
•
Tape Tension Measurement
Mode
Tension Meter
Meter Reading
FWD
CQ-403A
more than 100 g
(more than 3.53 oz)
0 dB=0.775 V
DECK SECTION
Procedure:
1. Mode: Playback
set
HEAD PHONE board
PHONES jack
(J500)
PHONES jack
(J500)
+
–
–
level meter
test tape
P-4-A063
(6.3 kHz, –10 dB)
P-4-A063
(6.3 kHz, –10 dB)
1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
•
Test Tape
RECORD/PLAYBACK HEAD AZIMUTH ADJUSTMENT
Note:
Remove the cover (azimuth) before this adjustment.
Tape
Signal
Used for
P-4-A063
6.3 kHz, -10 dB
Azimuth Adjustment
3. Mode: Playback
4. After the adjustments, apply suitable locking compound to
the pats adjusted.
Adjustment Location: Record/Playback/Erase Head
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
HEAD PHONE board
PHONES jack
(J500)
PHONES jack
(J500)
Note:
1.
CD Block is basically constructed to operate without adjustment.
2.
Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3.
Use an oscilloscope with more than 10 M
Ω
impedance.
4.
Clean the object lens by an applicator with neutral detergent when the
signal level is low than specified value with the following checks.
signal level is low than specified value with the following checks.
5.
Check the focus bias check when optical block is replaced.
FOCUS BIAS CHECK
Procedure :
1. Connect the oscilloscope to TP (RFACO) and TP (VC) on the
CD board.
2. Insert the disc (YEDS-18). (Part No. : 3-702-101-01)
3. Press the
3. Press the
CD
u
button.
4. Confirm that the oscilloscope waveform is as shown in the
figure below. (eye pattern)
A good eye pattern means that the diamond shape (
A good eye pattern means that the diamond shape (
◊
) in the
center of the waveform can be clearly distinguished.
•
RF signal reference waveform (eye pattern)
Checking Location:
TP
(RFACO)
TP (VC)
– CD BOARD (Conductor Side) –
+
–
–
CD board
TP (RFACO)
TP (VC)
TP (VC)
oscilloscope
(DC range)
VOLT/DIV: 0.2 V (with the 10: 1 probe in use.)
TIME/DIV: 500 ns
TIME/DIV: 500 ns
1.1
When observing the eye pattern, set the oscilloscope
for AC range and raise vertical sensitivity.
for AC range and raise vertical sensitivity.
0.2 Vp-p
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.
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
CD SECTION
Click on the first or last page to see other CMT-NEZ7DAB / HCD-NEZ7 service manuals if exist.