Sharp CD-SW200 Service Manual page 75

(1) Focus-HF system check.
Although a CD is inserted and the cover is closed, "NO DISC" is
displayed.
Press the Tray1 CD Eject Button without inserting a disc, and try
starting the playback operation.
1. Does the pickup move to the PICKUP-IN Switch (NSW1) posi-
tion ?
2. Does the focus (lens) move up and down ?
(Waveform drawing Figure 1)
3. Is the laser lit ?
4. Is the turntable rotating ?
When a disc is loaded, start playback operation.
1. Is focus servo activated ?
(Waveform drawing Figure 2)
2. Is the HF waveform normal ?
(Waveform drawing Figure 3)
Stopped
CH1=500 mV CH2=10 V
DC 10:1 DC 10:1
FDO
1
T
2
TE
3
CH Position To
-3 div -1 div 0 div
=Filter= =Offset=
Smoothing : ON CH1 : 0.000 V
BW : FULL CH2 : 0.0 V
CH3 : 0.00 V
CH4 : 0.00 V
Figure 2
Yes
Yes
Yes
Yes
CH3=1 V 500 ms/div
DC 10:1 (500 ms/div)
NORM:20 kS/s
CH2
Position
0.20 div
+1 div +3 div
=Record Length= =Trigger=
Main : 100 K Mode : AUTO
Zoom : 2 K Type : EDGE CH1
Delay : 0.0 ns
Hold off : 0.2 µs
Stopped
CH1=500 mV
DC 10:1
T
FDO
1
TDO
3
=Filter= =Offset=
Smoothing : ON CH1 :
BW : FULL
CH2 :
CH3 :
CH4 :
No Sled motor (NM2).
No Check the focus peripheral circuit.
No Check the laser diode driver Q1 peripheral circuit.
No Spindle motor (NM1).
No Pins 5~9, 11, 18 and 19 on IC1
Check the laser diode driver Q1 peripheral circuit.
No If the level is not normal.
7 – 2
CD-SW200
CH3=500 mV 500 ms/div
DC 10:1 (500 ms/div)
NORM:20 kS/s
CH1
v/DIV
500 mV
=Record Length= =Trigger=
0.000 V Main : 100 K Mode : AUTO
0.0 V Zoom : 2 K Type : EDGE CH1
0.000 V Delay : 0.0 ns
0.00 V Hold off : 0.2 µs
Figure 1
Vp-p=1.0 V~1.3 V
0.5 mV/div,0.5 µsec/div
Figure 3