— 13 —
IC03
VR02
VR01
R07
IC01
CN12
Focus Gain
Focus Bias
RF Level
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 10M
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.
Adjust the focus bias adjustment when optical block is replaced.
Focus Bias Adjustment
RF Level Check
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.
oscilloscope
level: 1.0 Vp-p
VOLT/DIV: 200 mV
TIME/DIV: 500 nS
+0.3
–0.2
Adjustment Location: CD DECODER board
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 voltmeter 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.
Therefore, do not perform this adjustment.
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 —
CD DECODER
board
CN12
FEO
VC
DC voltmeter
+
–
CD DECODER
board
TP (RF)
CN12 (VC)
