Sony CDP-791 - SECTION 3 ELECTRICAL BLOCK CHECKING; RF Level and S Curve Diagnostic Checks; E-F Balance and Frequency Checks

SECTION
3
ELECTRICAL
BLOCK
CHECKING
CDP-791/X1
1
1ES
Note
:
1.
CD Block basically constructed to operate with-
out adjustment. Therefore,
check
each
item
in
order given.
2. Use
YEDS-18 disc
(3-702-101-01)
unless
otherwise
indicated.
3. Use the oscilloscope
with more than 10MJ? 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.
RF Level Check
S
Curve
Check
BD board
TP
(FEO)
TP (VC)
oscilloscope
JP
Procedure :
1
1
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 3±lVp-p.
S
curve waveform
symmetry
within 3±lVp-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.
BO board
Tp"(RF)
O
TP
(VC)
O
oscilloscope
-P
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
oscilloscope
waveform
is
clear and
check
RF
signal level
is correct
or not.
Note
:
Clear
RF signal waveform
means that the
shape
“0”
can
be ^clearly
distinguished at the
center of the wave-
form.
RF signal
waveform
VOLT/DIV
: 200mV
TIME/DIV
:500nS
T
level
:
v
p-p
E-F
Balance
Check
BD board
oscilloscope
TP
(TEO)
TP (VC)
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 0V,
and
check
this level;
Traverse
oscilloscope
,v
—drntewfHr
— —
L symmetry
level:
2±lVp-p
6.
Remove
the
lead
wire
connected
in step 1.
-
5
-