44
MXD-D400
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 10M
Ω
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
Connection:
Procedure:
1. Connect oscilloscope to test point TP (FE) and TP (VC) on
BD (CD) board.
2. Turn the power on.
3. Put disc (YEDS-18) in.
4. Enter the test mode , select the BU Test and press
the
l
AMS
L
(CD) knob to display “bdt S CURVED”.
5. Press the
l
AMS
L
(CD) knob. “LD AL” is displayed
and playback starts automatically.
6. 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.
7. Press the
[MENU/NO]
button to stop playback.
8. Exit from the test mode.
(Refer to the TEST MODE Section)
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 (see page 45)
RF Level Check
Connection:
Procedure:
1. Connect oscilloscope to test point TP (RFDC) 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.
+
–
BD (CD) board
TP (FE)
TP (VC)
oscilloscope
(DC range)
A
B
symmetry
within 3.6
±
0.5 Vp-p
+
–
BD (CD) board
TP (RFDC)
TP (VC)
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
Checking Location: BD (CD) board (see page 45)
E-F Balance (1 Track Jump) Check
Connection:
Procedure:
1. Connect oscilloscope to test point TP (TE) and TP (VC) on
BD (CD) board.
2. Press the
?
/
1
button to turn the power on.
3. Put disc (YEDS-18) in to play the number five track.
4. Enter the service mode, press the
[INPUT]
button until “TRV
ON” is displayed. (The tracking servo and the sledding servo
are turned OFF)
5. Rotate RV101 on BD (CD) board to adjust A (DC voltage) of
the center of the oscilloscope waveform becomes 0 V.
6. Enter the service mode, press the
[INPUT]
button until “TRV
ON” is displayed (The tracking servo and the sledding servo
are turned OFF), confirm A (DC voltage) at that time is 0 V.
Traverse Waveform
Checking Location: BD (CD) board (see page 45)
Adjustment after CD Base Unit (BU-30BBD61B) is Replaced
Perform the “E-F Balance (1 track jump) check”.
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
(normal speed)
level: 1.1
±
0.3 Vp-p
+
–
BD (CD) board
TP (TE)
TP (VC)
oscilloscope
(DC range)
0V
Center of
waveform
B
Symmetry
A (DC voltage)
level=1.1
±
0.6Vp-p
