Cd Section - Sony MXD-D5C 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 10MΩ 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.
5. Level doesn't change whichever with normal speed or with four times
speed.
S Curve Check
Connection:
BD (CD) board
TP (FE)
TP (VC)
Procedure:
1. Connect oscilloscope to test point TP (FE) and TP (VC) on BD
(CD) board.
2. Turn ON the power.
3. 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.)
4. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within 3.6 ±
0.5 Vp-p.
S-curve waveform
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.
Check Location: BD (CD) board
RF Level Check
Connection:
BD (CD) board
TP (RF)
TP (VC)
Procedure:
1. Connect oscilloscope to test point TP (RF) and TP (VC) on BD
(CD) board.
2. Turn ON the power.
3. Put disc (YEDS-18) in to play the number five track.
4. Confirm that oscilloscope waveform is clear and check RF sig-
nal level is correct or not.
46
oscilloscope
(DC range)
+
–
symmetry
A
within 3.6 ± 0.5 Vp-p
B
oscilloscope
(AC range)
+
–
Note: A clear RF signal waveform means that the shape "◊" can be clearly
distinguished at the center of the waveform.
RF signal waveform
Check Location: BD (CD) board
E-F Balance Check
Connection:
BD (CD) board
TP4 (TE)
TP (VC)
Procedure:
1. Connect oscilloscpe to test point TP (TE) and TP (VC) on BD
(CD) board.
2. Turn ON the power.
3. Put disc (YEDS-18) in to play the number five track.
[ AMS ]
4. Press the l L
at the service mode. (The tracking servo and the sledding servo
are turned OFF)
5. Check the level B of the oscilliscope's waveform and the A (DC
voltage) of the center of the Traverse waveform.
Confirm the following :
A/B x 100 = less than ± 22%
Traverse Waveform
0V
[ AMS ]
6. Press the
l L
sledding servo are turned ON)
Confirm the C (DC voltage) is almost equal to the A (DC volt-
age) is step 5.
Traverse Waveform
0V
Tracking servo
Sled servo
Check Location: BD (CD) board
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
(normal speed)
level: 1.2 ± 0.2 Vp-p
oscilloscope
(DC range)
+
–
(MD) knob to display "9> TRK ON"
Center of
the waveform
B
A (DC
level: 1.3 ± 0.6 Vp-p
(MD) knob. (The tracking servo and
Tracking servo
Sled servo
OFF ON
voltage)
C (DC
voltage)