Cd Section - Sony HCD-GRX9900 Service Manual

CD SECTION

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 M 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).
2. Connect between TP (FE1) and TP (VC) by lead wire.
3. Connect between TP (AGCCON) and TP (GND) by lead wire.
4. Turn the power ON.
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).
2. Connect between TP (AGCCON) and TP (GND) by lead wire.
3. Turn the power ON.
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.
oscilloscope
+
–
symmetry
A
within 4 1 Vp-p
B
oscilloscope
+
–
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 oscilloscpe to TP (TE) and TP (VC).
2. Turn the power ON.
3. Load a disc (YEDS-18) and playback the number five track.
4. Press the ^ (CD) button. (Becomes the 1 track jump mode)
5. Confirm that the level B and A (DC voltage) on the oscillo-
scope waveform.
1 track jump waveform
0V
level = 1.3
A
Specified level:
B
6. After check, remove the lead wire connected in step 1.
– 17 –
oscilloscope
+
–
B
0.6 Vp-p symmetry
100 = less than ± 22%
center of
waveform
A (DC voltage)