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CD SECTION
Note:
1.
CD Block is basically constructed to operate without
adjustment. Therefore, check each item in order given.
2.
Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3.
Use an oscilloscope with more than 10MΩ 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.
Adjust the focus bias adjustment when optical block is replaced.
Focus Bias Adjustment
CD DECODER
board
CN12
FEO
VC
Procedure:
1.
Connect DC voltmeter to test point CN12 (FEO), (VC) on CD
DECODER board.
2.
Turned Power switch on.
3.
Put disc (YEDS-18) in and stop.
4.
Adjust VR01 so that the DC voitmeter reading is 0 ± 20 mV.
Adjustment Location: CD DECODER board
Focus Gain Adjustment (VR02)
This gain has a margin, so even if it is slightly off.
There is no problem.
Therfore, do not perform this adjusment.
Please note that it should be fixed to mechanical center position
when you moved and do not know original position.
Adjustment Location
[CD DECODER BOARD] — Component side —
DC voltmeter
+
–
Focus Gain
CN12
VR02
IC03
IC01
VR01
R07
Focus Bias
RF Level Check
CD DECODER
board
TP (RF)
CN12 (VC)
Procedure :
1.
Connect oscilloscope to test point TP (RF) on CD DECODER
board.
2.
Turned Power switch on.
3.
Put disc (YEDS-18) in and playback.
4.
Confirm that oscilloscope waveform is clear and check RF
signal level is correct or not.
Note: Clear RF signal waveform means that the shape "◊" can be
clearly distinguished at the center of the waveform.
Adjustment Location: CD DECODER board
RF Level
— 13 —
oscilloscope
VOLT/DIV: 200 mV
TIME/DIV: 500 nS
+0.3
level: 1.0
Vp-p
–0.2
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