Checking The Spin System; Checking The Vco-Pll System - Sharp CD-C831W Service Manual

CD-C831W

• Checking the spin system.

Play operation is performed without disc.
The turntable rotates a little.
The turntable fails to rotate or rotates at high speed.

• Checking the VCO-PLL system

Play operation is performed when disc exits.
Although HF waveform is normal, TOC data cannot be read.
0.5s
1.00 V
IC2 3 PDO
0.5s
1.00 V
IC2 16 FD
Figure 38
• Although HF waveform is normal and the time
indication is normal, no sound is emitted.
Check IC 2 pin 48 (EFLG).
Check IC2 pins 37, 40.
Yes
No
Yes
Stop --> Play
As VCO freque-
ncy is locked at
4.32 M Hz, voltage
of PDO rises and
stabilizes.
2
3
Yes
Yes
The spin driver circuit is normal.
Yes
Check the periphery of IC1 pins 23 to 27, pin 39, and pin 40, IC2
pin 12 and pin 13, IC3 to CNP3.
Yes
Check PDO waveform (Fig. 38).
Abnormal
Check the IC1 pins 43 and 44, IC2 pins 3, 5, 7, 10, and 11.
No
Usually, the number of pulses of flawless disc is 100 pulses/sec
or less.
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