Sony HCD-GP5, Service Manual

Page: 15 / 52

15
HCD-GP5
RFDC signal waveform
Checking Location: CD board (Conductor side)
RFAC Level Check
Connection:
Procedure:
1.
Connect an oscilloscope to test point TP (RFAC) and TP (VC)
on the CD 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.
RFAC signal waveform
Checking Location: CD board (Conductor side)
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 an oscilloscope to test point TP (FE) and TP (DVC)
on the CD board.
2. Turn the power on.
3. Put the 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 2 ± 1
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.
Checking Location: CD board (Conductor side)
RFDC Level Check
Connection:
Procedure:
1.
Connect an oscilloscope to test point TP (RFDC) and TP (DVC)
on the CD 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 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.
+
–
CD board
TP (FE)
TP (DVC)
oscilloscope
A
B
symmetry
within 2
±
1 Vp-p
+
–
CD board
TP (RFDC)
TP (DVC)
oscilloscope
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 0.7
±
0.2 Vp-p
+
–
CD board
TP (RFAC)
TP (VC)
oscilloscope
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 0.9
±
0.4 Vp-p