Sharp CD-XP500 Service Manual page 44

CD-XP500/CD-XP5500
(4) PLL system check.
When a disc is loaded, start play operation.
The HF waveform is normal, but the TOC data cannot be
read.
Check the PDO waveform. (Figure 44-1)
Check around pins 73~78 on IC1.
(5) Others.
The HF waveform is normal and the time is displayed
normally, but no sound is produced. Or the sound
has dropouts.
Is pin 52 (C2F) on IC1 "L" ?
1. When playing at normal speed
Check the peripheral circuit at pin 39 (DOUT) on IC1 and
the waveform (Figure 44-2).
If OK, Check the unit.
Yes
Stopped
CH1=500 mV
DC 10:1
PDO1
3
4
PDO2
T
FDO
1
=Filter=
Smoothing : ON
BW : FULL
No
There are too many error flags on a damaged disc which
makes error correction impossible.
Check again using a known good disc.
Stopped
CH1=2 V
DC 10:1
T
1
DOUT
=Filter=
Smoothing : ON
BW : FULL
– 44 –
1999/04/05 17:33:17
CH3=1 V CH4=1 V
DC 10:1 DC 10:1
=Offset= =Record Length=
CH1 : 0.000 V Main : 100 K Mode : AUTO
CH2 : 0.0 V Zoom : 2 K Type : EDGE CH2
CH3 : 0.00 V Delay :
CH4 : 0.00 V Hold off :
Figure 44-1
T
1999/04/07 09:25:28
=Offset= =Record Length= =Trigger=
CH1 : 0.00 V Main : 1 K Mode : NORMAL
CH2 : 0.00 V Zoom : 100 Type : EDGE CH1
CH3 : 0.00 V Delay :
CH4 : 0.00 V Hold off :
Figure 44-2
500 ms/div
(500 ms/div)
NORM:20 kS/s
CH1
v/DIV
500 mV
=Trigger=
0.0 ns
0.2 µs
500 ns/div
(500 ns/div)
NORM:200 MS/s
2.887 ms
0.2 µs