Read Sony CMT-EH20DAB / HCD-EH20DAB Service Manual online
11
HCD-EH20DAB
4. After the adjustments, apply suitable locking compound to
the pats adjusted.
Adjustment Location: Record/Playback/Erase Head
CD SECTION
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.
5.
Check the focus bias check when optical pick-up block is replaced.
FOCUS BIAS CHECK
Procedure :
1. Connect oscilloscope to TP (RFACI) and TP (VC) on the CD
board.
2. Press the
I/
1 button to turn the power ON.
3. Set disc (YEDS-18) on the tray and press the
CD
u button
to playback.
4. Confirm that oscilloscope waveform is as shown in the figure
below. (eye pattern)
A good eye pattern means that the diamond shape (
◊
) in the
center of the waveform can be clearly distinguished.
Checking Location:
+
–
–
CD board
TP (RFACI)
TP (VC)
TP (VC)
oscilloscope
(DC range)
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
TIME/DIV: 500 ns
level:
0.9
0.9
±
0.4 Vp-p
TP
(VC)
TP
(RFACI)
IC201
– CD Board (Conductor Side) –
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