Electrical Checking - Sony CDP-CE245 Service Manual

Note:
1. CD Block is basically designed to operate without adjustment. There-
fore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10 MΩ impedance.
4. Clean the object lens by an applicator with neutral detergent when the
signal level is low than specified value with the following checks.
S-Curve Check
BD board
TP (FE)
TP (VC)
Procedure:
1. Connect oscilloscope to TP (FE) and TP (VC) on the BD board.
2. Connect between TP (FE1) and TP (VC) with lead wire.
3. Connect between TP (AGCCON) and TP (GND) with lead
wire.
[POWER]
4. Turned power switch (
5. Load a disc (YEDS-18) and actuate the focus search. (In con-
sequence of open and close the disc tray, actuate the focus
search)
6. Cofirm that the oscilloscope waveform (S-curve) is symmetri-
cal between A and B. And confirm peak to peak level within
4 ± 1 Vp-p.
S-curve waveform
7. After check, remove the lead wire connected in step 2 and 3.
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
BD board
TP (RF)
TP (VC)
Procedure:
1. Connect oscilloscope to TP (RF) and TP (VC) on BD board.
2. Connect between TP (AGCCON) and TP (GND) with lead
wire.
[POWER]
3. Turned power switch (
4. Load a disc (YEDS-18) and playback.
5. Confirm that the oscilloscope waveform is clear and check RF
signal level is correct or not.
6. After check, remove the lead wire connected in step 2.
Note: Clear RF signal waveform means that the shape "◊" can be clearly
distinguished at the center of the waveform.
14
SECTION 5

ELECTRICAL CHECKING

oscilloscope
+
–
button) on.
symmetry
A
within 4 ± 1 Vp-p
B
oscilloscope
+
–
button) on.
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.45 ± 0.3 Vp-p
E-F Balance (1 Track Jump) Check
BD board
TP (TE)
TP (VC)
Procedure :
1. Connect oscilloscope to TP (TE) and TP (VC) on BD board.
[POWER]
2. Turned power switch (
3. Load a disc (YEDS-18) and playback the number five track.
4. Press the button. (Becomes the 1 track jump mode)
H
5. Confirm that the level B and A (DC voltage) on the oscillo-
scope waveform.
1 track jump waveform
0V
level = 1.3 ± 0.6 Vp-p
A
× 100 = less than ± 22%
Specified level:
B
6. After check, remove the lead wire connected in step 1.
RF PLL Free-run Frequency Check
Procedure :
1. Connect frequency counter to TP (PLCK) with lead wire.
BD board
TP (PLCK)
[POWER]
2. Turned power switch (
3. Put the disc (YEDS-18) in to play the number five track.
Confirm that reading on frequency counter is 4.3218 MHz.
oscilloscope
+
–
button) on.
center of
waveform
B
A (DC voltage)
symmetry
frequency counter
+
–
button) on.