CD-BA1700 (serv.man9). Part 4 - Voltage table, Troubleshooting tables, IC tables - Sharp Audio Service Manual (repair manual). Page 4

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– 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)
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.
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.
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.
2. Does the focus (lens) move up and down?
    (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
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
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
Vp-p=1.0V~1.3V
0.5mV/div,0.5
µ
sec/div
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