23
CD SECTION
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 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.
S-Curve Check
Procedure :
1. Connect oscilloscope to TP (FEO).
2. Connect between TP (FEI) and TP (VC) by lead wire.
3. Connect between TP (AGCCON) and TP (GND) by lead wire.
4. Press the "/1 button to turn ON the power.
5. Load a disc (YEDS-18) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
6. Confirm that the oscilloscope waveform (S-curve) is
symmetrical between A and B. And confirm peak to peak level
within 4 ±1 Vp-p.
7. After check, remove the lead wire connected in step 2 and 3.
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
Procedure :
1. Connect oscilloscope to TP (RF).
2. Connect between TP (AGCCON) and TP (GND) by lead wire.
3. Press the "/1 button to turn ON the power.
4. Load a disc (YEDS-18) and playback.
5. Confirm that oscilloscope waveform is clear and check RF signal
level is correct or not.
6. After check, remove the lead wire connected in step 2.
BD board
Oscilloscope
TP(FEO)
TP(VC)
symmetry
S-curve waveform
within 4 ±1Vp-p
A
B
TP(RF)
TP(VC)
BD board
oscilloscope
Note: Clear RF signal waveform means that the shape “◊” can be
clearly distinguished at the center of the waveform.
RF signal waveform
E-F Balance (1 Track jump) Check
Procedure:
1. Connect oscilloscope to TP (TEO) and TP (VC) board.
2. Press the "/1 button to turn ON the power.
3. Load a disc (YEDS-18) and playback the number five track.
4. Press the u button. (Becomes the 1track jump mode.)
5. Confirm that the level B and A (DC voltage) on the oscilloscope
waveform.
1 track jump waveform
Specification level: x 100=less than ±22%
6. After check, remove the lead wire connected in step 1.
RF PLL Free-run Frequency
Procedure :
1. Connect frequency counter to test point (XPCK) with lead wire.
2. Press the "/1 button to turn ON the power.
3. Put the disc (YEDS-18) in to play the number five track.
Confirm that reading on frequency counter is 4.3218MHz.
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.45 ± 0.3Vp-p
oscilloscope
BD board
TP (TEO)
TP (VC)
+
–
0V
Center of
waveform
B
Symmetry
A (DC voltage)
level=1.3±0.6Vp-p
A
B
+
–
frequency counte
BD board
TP (XPCK)
w
w
w
.
x
i
a
o
y
u
1
6
3
.
c
o
m
Q
Q
3
7
6
3
1
5
1
5
0
9
9
2
8
9
4
2
9
8
T
E
L
1
3
9
4
2
2
9
6
5
1
3
9
9
2
8
9
4
2
9
8
0
5
1
5
1
3
6
7
3
Q
Q
TEL 13942296513 QQ 376315150 892498299
TEL 13942296513 QQ 376315150 892498299
http://www.xiaoyu163.com
http://www.xiaoyu163.com
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