Sony CDP-C265 - Page 31

ELECTRICAL BLOCK CHECKING (for BU-5BD23)
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.
Use an oscilloscope with more than 1OMQ impedance.
Clean the object lens by an applicator with neutral detergent
when the signal level is low than specified value with the
following checks.
ata
S Curve Check
oscilloscope
O
anaes +
O<——0 -
BD board
af
TP(FE)
TP(VC)
Procedure :
1. Connect oscilloscope to test point TP (FE) on BD board.
2. Connect between test point TP (FEI) and TP (VC) by lead
wire.
3. Turned Power switch on.
4. Put disc (YEDS-18) in and turned Power switch on again
and actuate the focus search. (actuate the focus search when
disc table is moving in and out.)
5. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within
3+1 Vp-p.
S-curve waveform
symmetry
within 3£1 Vp-p
6. 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.
RF Level Check
oscilloscope
BD board
Procedure :
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turned Power switch on.
3. Put disc (YEDS-18) in to play the number five track.
4. Confirm that oscilloscope waveform is clear and check RF
signal level is correct or not.
Note :
A clear RF signal waveform means that the shape “()” can
be clearly distinguished at the center of the waveform.
RF signal waveform
VOLT/DIV : 200mV
TIME/DIV : 500nS
O70)
(4
WY
WRT
AR
MAMMA
1.2 +0.25
level : “920 VP-P
E-F Balance Check
oscilloscope
BD board
oT
TP(TE) O@——-oF
TP(VC) o«—lo-
Procedure :
Connect test point TP (ADJ) to ground with lead wire.
Connect oscilloscpe to test point TP (TE) on BD board.
Turned Power switch on.
Put disc (YEDS-18) in to play the number five track.
Press the “3” button. (The tracking servo and the sledding
servo are turned OFF.)
Check the level B of the oscilloscope’s waveform and the
A (DC voltage) of the center of the Traverse waveform.
Confirm the following :
A/B x 100 = less than + 20%.
hin salar ea
a
Traverse waveform
UU
IAT
{
Center of the waveform
|
A (DC voltage)
level : 1.5£0.7 Vp-p
7. Press the “8” button. (The tracking servo and sledding
servo are turned ON.) Confirm the C (DC voltage) is
almost equal to the A (DC voltage) in step 6.
Traverse waveform
AIM
C (DC
voitage)
Tracking servo
Sledding servo
ON
Tracking servo
Siedding servo +}.
OFF
8. Disconnect the laed wire of TP (ADJ) connected in step 1.