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SECTION
3
ELECTRICAL BLOCK CHECKING
Note:
1.
CD Block basically constructed
to operate with-
out
adjustment.
Therefore,
check
each
item in
order given.
Use YEDS-18 disc (3-702-101-01) unless otherwise
indicated.
bw
3.
Use the oscilloscope
with
more
than
10M/2
im-
pedance.
4.
Clean an object lens by an applicator with neutral
detergent
when
the
signal
level
is low
than
specified value with the following checks.
S Curve Check
oscilloscope
BD
board
ae,
TP (FEO)
O———oF
TP (VC)
ow—lo-
Procedure :
1.
Connect oscilloscope to test point TP (FEO) on
BD board.
2.
Connect
between
test point TP
(FES)
and TP
(VC) by lead wire.
3.
Turned
Power
switch
on and actuate
the focus
serch. (actuate the focus serch when disc table is
moving in and out.)
4.
Check
the
oscilloscope
waveform
(S curve)
is
symmetrical between A and B. And confirm peak
to peak level within 341Vp-p.
S curve waveform
symmetry
oe
within
3+1Vp-p
5.
After check, remove
the lead wire connected
in
step 2.
Note:
+ Try to mesure
several
times
to make
sure
that 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
oscilloscope
BD
board
oo.
|O
TP (RF) O<t—0F
TP (VC) O=—0 -
Procedure :
1.
Connect
oscilloscope to test point TP
(RF) on
BD board.
Turn Power switch on.
Put disc (YEDS-18) in and playback.
Confirm that oscilloscope waveform
is clear and
aw
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 wave-
form.
VOLT/DIV
: 200mV
TIME/DIV
:500nS
+0.2
—o.4 VP-P
RF signal waveform
VAXARAAXKXAKK)
\
es
WAIN
IE
E-F Balance Check
oscilloscope
©
CDN
TP(TEO)
O~—-—oF
TP (VC)
O=—t—0 -
BD
board
Procedure :
1.
Connect test point TP (ADJ) to ground and TP
(TES) to TP (VC) with lead wire.
2.
Connect oscilloscope to test point TP (TEO) on
BD board.
3.
Turn Power switch on.
4.
Put disc (YEDS-18) in and playback.
5.
Confirm
that
the osilloscope
waveform
is sym-
metrical on the top and bottom in relation to OV,
and check this level.
Traverse oscilloscope
symmetry
level: 2+1Vp-p
6.
Remove the lead wire connected in step 1.
—7T—
RF PLL Free-run Frequency Check
4-1.
CIRCUIT BOARDS
Procedure :
Adjustment Locations :
{BD board)
1.
Connect
frequency counter
to test point (PCK)
L Jcansuciercde=
with lead wire.
frequency
counter
Main board
ie
J
Fibs ot
TP (PCK) re
Turn Power switch on.
3.
Confirm that reading on frequency counter is
4, 3218MHz.
Focus/Tracking Gain
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 cen-
DISPLAY BOAR
ter position when you
moved and do not know
original position.
{Main board)
CXA1291P
12
10
J
7
CXD2500AQ
CXP50116-213Q
MARKING SIDE VIEW
CXD2560M
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