Read Sharp CD-BA1700 (serv.man9) Service Manual online
– 41 –
CD-BA160H/1700H
If the level is not normal, check around pins 27~29 on IC1.
1. Is focus servo activated? (Waveform drawing 41-2)
Pins 1~11 on IC1
Check the laser diode driver Q3 peripheral circuit.
Focus error circuit (pins 20 and 21 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 41-3)
Check the spin system.
If the disc is spinning and a HF waveform is generated,
DRF will go H.
DRF will go H.
Figure 41-1
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.
DISC" is displayed.
1. Did 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.
disc, and try starting the playback operation.
2. Does the focus (lens) move up and down?
(Waveform drawing 41-1).
(Waveform drawing 41-1).
Check the focus peripheral circuit.
3. Is the laser lit?
Spindle motor (M1).
4. Is the turntable rotating?
Figure 41-2
Figure 41-3
Yes
Yes
Yes
No
No
No
No
No
No
No
Yes
Yes
No
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
CH2 : 0.0V
Main : 100K
Zoom : 2K
Zoom : 2K
Mode : AUTO
Type : EDGE CH1
Delay : 0.0ns
Hold off : 0.2us
Type : EDGE CH1
Delay : 0.0ns
Hold off : 0.2us
CH3 : 0.000V
CH4 : 0.00V
CH4 : 0.00V
BW : FULL
=Trigger=
=Filter=
=Offset=
CH1
v/DIV
500mV
v/DIV
500mV
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
CH2 : 0.0V
Main : 100K
Zoom : 2K
Zoom : 2K
Mode : AUTO
Type : EDGE CH1
Delay : 0.0ns
Hold off : 0.2us
Type : EDGE CH1
Delay : 0.0ns
Hold off : 0.2us
CH3 : 0.00V
CH4 : 0.00V
CH4 : 0.00V
BW : FULL
=Trigger=
=Filter=
=Offset=
-3div
-1div
0div
+1div
+3div
CH Position To
CH2
Position
0.20div
Position
0.20div
Vp-p=1.0V~1.3V
0.5mV/div,0.5
µ
sec/div
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