QT-CD121
– 20 –
The turntable fails to rotate or rotates at high speed.
Yes
Check the periphery of IC801 pins 23 to 27, pin 39 and pin 40,
IC802 pin 12 and pin 13, IC804 to BI803/CNS803.
The turntable rotates a little.
Yes
The spin driver circuit is normal.
Play operation is performed without disc.
• Checking the spin system.
No
Yes
Check the IC801 pins 43 and 44, IC802 pins 3, 5, 7, 9 and 10.
Error
Yes
Check PDO waveform (Fig. 20).
• Checking the VCO-PLL system
Play operation is performed when disc exits.
Yes
Although HF waveform is normal, TOC data cannot be read.
Figure 20
2
3
0.5s
1.00 V
IC802 3 PDO
0.5s
1.00 V
IC801 16 FD
As VCO freque-
ncy is locked at
4.32 M Hz,
voltage of PDO
rises and stabili-
zes.
Stop --> Play
Check IC802 pins 37and 40.
Check the periphery of IC803 (OPAMP).
Abnomal
Usually, the number of pulses of flawless disc is 100 pulses/sec
or less.
No
Yes
Check IC802 pin 48 (EFLG).
• Although HF waveform is normal and the time
indication is normal, no sound is emitted.
Summary of Contents for QT-CD121
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