Cd Section - Sony HCD-MD1EX - System Service Manual

CD SECTION

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.
3. Use an oscilloscope with more than 10 M impedance.
4. Clean the object lens by an applicator with lens cleaning liq-
uid when the signal level is low than specified value with the
following checks.
5. Adjust the focus bias adjustment when optical block is replaced.
Focus Bias Adjustment
Perform this adjustment when the optical pick-up has been re-
placed or repaired.
BD (CD) board
TP (RF)
TP (VC)
Procedure:
1. Connect oscilloscope to test point TP (RF).
2. Turn Power switch on.
3. Put disc (YEDS-18) in and playback.
4. Adjust RV101 so that the waveform is clear.
(Clear RF signal waveform means that the shape "≈" can be
clearly distinguished at the center of the waveform.)
5. After adjustment, check the RF signal level.
• RF signal
VOLT/DIV: 200 mV
TIME/DIV: 500 nS
oscilloscope
+
–
level : 1.3 0.3 Vp-p
S Curve Check
BD (CD) board
TP (FEO)
TP (VC)
Procedure :
1. Connect oscilloscope to test point TP (FEO).
2. Connect between test point TP (FOK) and Ground by lead
wire.
3. Turn 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 be-
tween A and B. And confirm peak to peak level within 2.4 ±
0.7 Vp-p.
S-curve waveform
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
BD (CD) board
TP (RF)
TP (VC)
Procedure :
1. Connect oscilloscope to test point TP (RF) on BD (CD) 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 "≈" can be clearly
distinguished at the center of the waveform.
RF signal waveform
– 31 –
oscilloscope
+
–
symmetry
A
within 2.4 0.7 Vp-p
B
oscilloscope
+
–
VOLT/DIV : 200 mV
TIME/DIV : 500 nS
level : 1.3 0.3 Vp-p