Sharp QT-CD111H Service Manual page 21

• Checking the spin system.
Play operation is performed without disc.
Yes
The turntable rotates a little.
No
The turntable fails to rotate or rotates at high speed.
• Checking the VCO-PLL system
Play operation is performed when disc exits.
Yes
Although HF waveform is normal, TOC data cannot be read.
0.5s
1.00 V
IC802 3 PDO
0.5s
1.00 V
IC801 16 FD
Figure 21
• Although HF waveform is normal and the time
indication is normal, no sound is emitted.
Check IC802 pin 48 (EFLG).
Yes
Check IC802 pins 37and 40.
Abnomal
Check the periphery of IC803 (OPAMP).
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Yes
Yes
Yes
Stop --> Play
As VCO freque-
ncy is locked at
4.32 M Hz,
voltage of PDO
2
rises and stabili-
zes.
3
No
– 21 –
The spin driver circuit is normal.
Check the periphery of IC801 pins 23 to 27, pin 39 and pin 40,
IC802 pin 12 and pin 13, IC804 to BI803/CNS803.
Check PDO waveform (Fig. 21).
Error
Check the IC801 pins 43 and 44, IC802 pins 3, 5, 7, 9 and 10.
Usually, the number of pulses of flawless disc is 100 pulses/sec
or less.
QT-CD111H/110H