19
CX-JDS20/JDS50
CD SECTION
Note:
1. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
2. Use an oscilloscope with more than 10M
Ω
impedance.
3. 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 an oscilloscope to test point TP (FEO) and TP (VC)
on the BD board.
2. Set the FUNCTION to “CD”.
3. While depressing the
nN
button, insert an AC plug.
4. Put the disc (YEDS-18) in and press the
x
button 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
between A and B. And confirm peak to peak level within 2
±
1
Vp-p.
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.
Checking Location: BD board (Side B)(See page 20)
1. Connect an oscilloscope to test point (RFDCO) and TP (VC)
2. Turn the power on.
3. Put the disc (YEDS-18) in to playback the number five track.
4. Confirm that oscilloscope waveform is clear and check RFDC
signal level is correct or not.
Note:
A clear RFDC signal waveform means that the shape “
◊
” can
be clearly distinguished at the center of the waveform.
Checking Location: BD board (Side B)(See page 20)
RFAC Level Check
Connection:
Procedure:
1. Connect an oscilloscope to test point TP (RFACO) and TP
(VC) on the BD board.
2. Turn the power on.
3. Put the disc (YEDS-18) in to playback the number five track.
4. Confirm that oscilloscope waveform is clear and check RFAC
signal level is correct or not.
Note:
A clear RFAC signal waveform means that the shape “
◊
” can
be clearly distinguished at the center of the waveform.
Checking Location: BD board (Side B)(See page 20)
+
–
BD board
oscilloscope
TP (FED)
TP (VC)
S-curve waveform
symmetry
A
B
within 2
±
1 Vp-p
+
–
oscilloscope
RFDC signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 0.6
±
0.15 Vp-p
+
–
BD board
oscilloscope
TP (RFACO)
TP (VC)
RFAC signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.0
±
0.4 Vp-p
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