Read Sony CMT-NEZ3 / CMT-NEZ5 / HCD-NEZ3 / HCD-NEZ5 Service Manual online
14
HCD-NEZ3/NEZ5
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
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