Note :
1. CD Block is basically designed 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 impedance.
4. Clean the object lens by an applicatior 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
Procedure :
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turn Power switch on.
3. Put disc (YEDS-18) in and playback.
4. Confirm that osilloscope 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.
RF signal waveform
VOLT/DIV : 200mV
TIME/DIV : 500nS
Procedure :
1. Connect oscilloscope to test point TP (FEO).
2. Connect between test point TP (ADJ) on DISPLAY board to
Ground with a lead wire.
3. Turn Power switch on to set the ADJ mode.
4. Put disc (YEDS-18) in and set to the stop mode.
5. Press the “15” button and actuate the focus serach.
6. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within 2.4 ± 0.7
Vp-p.
S-curve waveform
level : 1.3 ± 0.3 Vp-p
Symmetry
within 2.4 ± 0.7 Vp-p
A
B
oscilloscope
BD board
TP(RF)
TP(VC)
7. After check, remove the lead wire connected in step 2.
Note : • Try to measure several times to make sure than the ratio of
A : B or B :A is more than 10 :7.
• Take sweep time as long as possible and light up the
brightness to obtain best waveform.
RF Level Check
SECTION 5
ELECTRICAL BLOCK ADJUSTMENTS
oscilloscope
(DC range)
BD board
TP(RF)
TP(VC)
Procedure :
1. Connect oscilloscope to test point TP (RF).
(Ground terminal : VC)
2. Turn Power switch on.
3. Put disc (YEDS-18) in and playback.
4. Adjust RV101 so that the waveform is clear.
(Clear RF signal waveform means that the shape “
◊
” can be clearly
distinguished at the center of the waveform.)
5. After adjustment, check the RF signal level.
• RF signal
VOLT/DIV : 200 mV
TIME/DIV : 500 nS
level
1.3 ± 0.3 Vp-p
TP(FEO)
TP(VC)
BD board
oscilloscope
S Curve Check
Note : Use the widely use remote commander with 20 keys for this
check.
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