Sharp CD-BA3000 - TROUBLESHOOTING; Focus-HF System Check

CD-BA3000
– 38 –
Vp-p=1.0V~1.3V
0.5mV/div,0.5µsec/div
5
IC1 27
T
FDO
DRF
TE
Stopped
CH1=500mV
DC 10:1
CH2=10V
DC 10:1
CH3=1V
DC 10:1
500ms/div
(500ms/div)
NORM:20kS/s
1
2
3
=Record Length=
Smoothing : ON CH1 : 0.000V
CH2 : 0.0V
Main : 100K
Zoom : 2K
Mode : AUTO
Type : EDGE CH1
Delay : 0.0ns
Hold off : 0.2us
CH3 : 0.00V
CH4 : 0.00V
BW : FULL
=Trigger==Filter= =Offset=
-3div -1div 0div +1div +3div
CH Position To
CH2
Position
0.20div
1
IC2 24
3
IC2 72
4
IC1 18 ,
IC2 16
T
FDO
TDO
Stopped
CH1=500mV
DC 10:1
CH3=500mV
DC 10:1
500ms/div
(500ms/div)
NORM:20kS/s
1
3
=Record Length=
Smoothing : ON CH1 : 0.000V
CH2 : 0.0V
Main : 100K
Zoom : 2K
Mode : AUTO
Type : EDGE CH1
Delay : 0.0ns
Hold off : 0.2us
CH3 : 0.000V
CH4 : 0.00V
BW : FULL
=Trigger==Filter= =Offset=
CH1
v/DIV
500mV
1
IC2 24
2
IC2 23
If the level is not normal, check around pins 27~29 on IC1.
1. Is focus servo activated? (Waveform drawing Figure 38-2)
Pins 1~11 on IC1
Check the laser diode driver Q3 peripheral circuit.
Focus error circuit (pins 20 and 21 on IC1)
When a disc is loaded, start playback operation.
2. Does DRF change from "L" to "H"?
Is the disc rotating?
3. Is the HF waveform normal? (Waveform drawing
Figure 38-3)
Check the spin system.
If the disc is spinning and a HF waveform is generated,
DRF will go H.
Figure 38-1
Check the laser diode driver Q3 peripheral circuit.
(1) Focus-HF system check
Although a CD is inserted and the cover is closed, "NO
DISC" is displayed.
1. Does the pickup move to the PICKUP-IN Switch (SW4)
position?
Sled motor (M2)
Press the OPEN/CLOSE switch (SW1) without inserting a
disc, and try starting the playback operation.
2. Does the focus (lens) move up and down?
(Waveform drawing Figure 38-1).
Check the focus peripheral circuit.
3. Is the laser lit?
Spindle motor (M1).
4. Is the turntable rotating?
Figure 38-2
Figure 38-3
Yes
Yes
Yes
No
No
No
No
No
No
No
Yes
Yes
No