Read Sharp XL-HP404 (serv.man10) Service Manual online
XL-HP404E/HP404H
7 – 3
Check the TE waveform at pin 17 on IC1.
(2) Focus-HF system check.
If the waveform shown in Figure 4 appears and soon after NO
DISC appears?
DISC appears?
Yes
The tracking servo is not activated.
Check the peripheral circuits at pins 16, 17 and 22 on IC1, and
FFC1.
Check the peripheral circuits at pins 16, 17 and 22 on IC1, and
FFC1.
No
"Initialization" is possible, but play is not possible?
Yes
A normal jump operation cannot be completed or the beginning
of the track cannot be found.
Check the around pin 22 on IC1.
of the track cannot be found.
Check the around pin 22 on IC1.
No
"Initialization" is not possible.
Data cannot be read. Check the VCO-PLL (Pin76~80 on IC1)
system.
system.
Figure 4
T
T
TE
DRF
Stopped
CH1=10 V
DC 10:1
CH2=1 V
DC 10:1
100 ms/div
(100 ms/div)
NORM:100 kS/s
2
1
=Record Length=
Smoothing : ON
CH1 :
0.0 V
CH2 :
0.00 V
Main :
100 K
Zoom :
2 K
Mode : NORMAL
Type : EDGE CH1
Delay :
Type : EDGE CH1
Delay :
2.924 ms
Hold off :
0.2 µs
CH3 :
0.00 V
CH4 :
0.00 V
BW : FULL
=Trigger=
=Filter=
=Offset=
(3) Spin system check.
Press the OPEN/CLOSE switch without inserting a disc, and
then try starting the play operation.
then try starting the play operation.
1. The turntable rotates a little?
(Waveform drawing Figure 5)
(Waveform drawing Figure 5)
Yes
The spin driver circuit is OK.
No
2. The turntable doesn't rotate.
Check around pin 24 on IC1, pins 3 and 4 on IC2, and CNW3.
Figure 5
T
T
FDO
SPDO
Stopped
CH1=200 mV
DC 10:1
CH2=500 mV
DC 10:1
500 ms/div
1999/04/07 09:51:15
(500 ms/div)
NORM:20 kS/s
2
1
=Record Length=
Smoothing : ON
CH1 :
0.000 V
CH2 :
0.000 V
Main :
100 K
Zoom :
2 K
Mode : NORMAL
Type : EDGE CH2
Delay :
Type : EDGE CH2
Delay :
2.924 ms
Hold off :
0.2 µs
CH3 :
0.00 V
CH4 :
0.00 V
BW : FULL
=Trigger=
=Filter=
=Offset=
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