
I
sEcTtoN
3
ELECTRICAL
BLOCK
CHECKING
Note :
1. CD Block basically constructedto operatewithout adjus.
tment. Therefore, check each item in order given.
2. UseYEDS-18
disc
(3-702.101-01)
unlessotherwiseindicat-
ed.
3. Use the oscilloscopewith more than 10MO impedance.
4. Clean an object lens by an applicator with neutral deter-
gent when the signal level is low than specified value
with the following checks.
SCurveCheck
BDboarcl
rP(FEO)
rP(vc)
Procedure :
l. Connect oscilloscope to test point TP (FEO) on BD
board.
2. Connect between test point TP (FES) and TP (VC) bv
leadwire.
Turned Power switch on and actuate the focus serch.
(actuatethe focus serchwhen disctable is moving in and
out.)
Check the oscilloscopewaveform (S curve) is symmetri.
cal between A and B. And confirm peak to peak level
within 3+ 1Vp-p.
S curve
wavelorm symm€try
within
3 tlVÈp
5. After check, remove the lead wire connectedin step 2.
Note : o Try to mesure several times to make sure that the
ratio of A : B or B : A is more than 10: 7.
o Take sweep
time aslong aspossible
and light up the
brightness to obtain best waveform.
RFLevelCheck
BD board
TP(RFO)
rP(vc)
Procedure :
1. Connect oscilloscope
to test point Tp (RFO) on BD
board
2. Turn Power switch on.
3. Put disc (YEDS.l8) in and playback.
4. Confirm that oscilloscopewaveform is clear and check
RF signal level is correct or not.
Note:
Clear RF signal waveform meansthat the shape"O" can be
clearly distinguished at the center of the waveform.
RF
signalwaveform VOLT/DlV:
20OmV
TIME/O|V:
5O0nS
level :
I 2:3:lVtp
E-F
Balance
Check
BP-
rP(TEO)
TP(VC)
l. Connect test point TP (ADJ) to ground and Tp (TES) to
TP (VC) with leadwire.
2. Connect oscilloscope
to test point TP (TEO) on BD
board.
3. Turn Power switch on.
4. Put disc (YEDS-l8)in and playback.
5 Confirm that the osilloscope
waveform issymmetrical on
the top and
bottom in relation
to 0V,and
checkthislevel
Traverse
oscilloscope
symrnetry
T
1
À
oscilloscope
oscilloscope
oscilloscooe
6. Remove the lead wire connected in step I
2+
lVpp