CMT-HP8V, HCD-HP8V - Sony Audio Service Manual (repair manual). Page 26

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26
HCD-HP8V
 CD SECTION
Note:
1.
CD Block is basically designed to operate without adjustment. Therefore,
check each item in order given.
2.
Use LUV-P01 (Part No. 4-999-032-01) 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
Procedure :
1. Connect an oscilloscope to TP68 (FE) and TP73 (DVC) on the
BD board.
2. Turn the power ON.
3. Load a disc (LUV-P01) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
4. Confirm that the oscilloscope waveform (S-curve) is
symmetrical between A and B. And confirm peak to peak level
within 2 ± 0.5 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.
RF  LEVEL  CHECK
Procedure :
1. Connect an oscilloscope CH1 to TP71 (RFDC), CH2 to TP72
(RFAC) and TP73 (DVC) on the BD board.
2. Turn the power ON.
3. Load a disc (LUV-P01) and playback the number nine track.
4. Confirm that oscilloscope waveform is clear and check if RF
signal level is correct or not.
– BD BOARD (Conductor Side) –
TP70
(TE)
TP68
(FE)
TP71
(RFDC)
TP73
(DVC)
TP72
(RFAC)
Note:
Clear RF signal waveform means that the shape “ 
◊ ” can be clearly
distinguished at the center of the waveform.
TRAVERSE LEVEL CHECK
Procedure :
1. Connect an oscilloscope to TP70 (TE) and TP73 (DVC) on the
BD board.
2. Turn the power ON.
3. Load a disc (LUV-P01) and playback the number nine track.
4. Press the  
CD
 N  button. (Becomes the 1 track jump mode.)
5. Confirm that the level B and A (DC voltage) on the oscilloscope
waveform.
Connecting Location:
level=1.2 
±
0.55Vp-p symmetry
A (DC voltage)
center of
waveform
B
DVC
1 track jump waveform
TP70 (TE)
TP73 (DVC)
BD board
+
oscilloscope
RF signal waveform
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 0.75 
±
0.1Vp-p (RFDC)
1.05 
±
0.3Vp-p (RFAC)
+
oscilloscope
TP71 (RFDC)
TP72 (RFAC)
BD board
TP73 (DVC)
symmetry
S-curve waveform
within 2 
±
0.5Vp-p
A
B
+
oscilloscope
BD board
TP68 (FE)
TP73 (DVC)
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