17
HCD-VM330AV
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 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.
S-Curve Check
Procedure :
1. Connect an oscilloscope to TP (FEO) and TP (DVC).
2. Connect between TP (FEI) and TP (VC) by lead wire.
3. Turn Power switch on.
4. Load the disc (YEDS-18) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
5. 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.
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.
Procedure :
1. Connect an oscilloscope to TP (RFAC) and TP (DVC).
2. Turn Power switch on.
3. Load the disc (YEDS-18) and playback.
4. Confirm that the oscilloscope waveform is clear and check RF
signal level is correct or not.
5. Measure the RFDC in the same way.
BD board
Oscilloscope
TP(FEO)
TP(DVC)
symmetry
S-curve waveform
within 4
±
1Vp-p
A
B
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 an oscilloscope to TP (TEO) and TP (DVC).
2.
Turn Power switch on.
3.
Load the disc (YEDS-18) and playback the number five track.
4.
Press the
X
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 Check
Procedure :
1.
Connect a frequency counter to TP (XPCK) and GND.
2.
Turn Power switch on.
3.
Load the disc (YEDS-18) and playback the number five track.
4.
Confirm that the reading on frequency counter is 4.3218MHz.
oscilloscope
BD board
TP (TEO)
TP (DVC)
+
–
A
B
+
–
frequency counter
BD board
TP (XPCK)
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.1
±
0.3Vp-p
0V
Center of
waveform
B
Symmetry
A (DC voltage)
level=1.3
±
0.6Vp-p
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