Focus-Hf System Check - Sharp XL-MP130 Service Manual

XL-MP130

(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 (SW1A) 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)
Figure 2
Yes
Yes
Yes
Yes
No Sled motor (M2A).
No Check the focus peripheral circuit.
No Check the laser diode driver Q1 peripheral circuit.
No Spindle motor (M1A).
No Pins 8~11, 14 and 18,19 on IC1
Check the laser diode driver Q1 peripheral circuit.
No If the level is not normal.
7 – 2
Figure 1
Vp-p=1.0 V~1.3 V
0.5 mV/div,0.5 µsec/div
Figure 3