Electrical Block Checking - Sony CDP-2700 Service Manual

| CDP-2700
SECTION 2
ELECTRICAL BLOCK CHECKING
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 10M22 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
A
TP (FEO) o«—o}
TP (VC) oO——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
within 31Vp-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
asm
TP (RFO) O=t-—~o +
TP (VC) ow—lo-
Procedure :
1. Connect oscilloscope to test point TP (RF) on
BD board.
2. Turn Power switch on.
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 "©"
can be clearly distinguished at the center of the wave-
form.
VOLT/DIV : 200mV
RF signal waveform TIME/DIV : 500nS
)
Wii
\AK?
Ny
V
level :
+0.2
i 1204 Vp-p
\ AN
AVY)
N00 N
\\ N \A}
\WX HNN
y NAN WW
i
E-F Balance Check
oscilloscope
BD board
©
TP (TEO) oa—;° +
TP (VC) O=t——0 -
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.
Put disc (YEDS-18) in and playback.
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.