QT-CD121
– 18 –
TROUBLESHOOTING
When the CD does not function
When the CD section does not operate When the objective lens of the optical pickup is dirty,this section may not operate.Clean
the objective lens,and check the playback operation.When this section does not operate even after the above step is taken,check
the following items.
Remove the cabinet and follow the troubleshooting instructions.
"Track skipping and/or no TOC(Table Of Contents) may be caused by build up of dust other foreign matter on the laser pickup lens.
Before attempting any adjustment make certain that the lens is clean. If not, clean it as mentioned below."
Turn the power off.
Gently clean the lens with a lens cleaning tissue and a small amount of isopropyl alcohol.
Do not touch the lens with the bare hand.
See if the pick-up is in the pick-up in SW702 position.
If the items mentioned above are OK, check the main
microcomputer IC701.
Yes
Yes
• The CD function will not work.
The CD operating keys don't work.
Check the CD, DPS microcomputer (IC701), power supply, 4.19
MHz and 16.93 MHz clock, and reset terminal.
Check the waveform of SCK, SO (DATA) and SI (COMM).
Yes
Yes
Playback can be performed without a disc.
Yes
Does the output waveform of IC801(16)(FD) match that shown in
Fig. 18?
Check the area around IC804-BI801/CNS801.
Yes
Check the IC801(50)(CLK) line, 4MHz.
Check the microcomputer data on pins (51)(CL), (52)(DAT) and
(53)CE.
Figure 18
• The CD operating keys work.
No
Yes
No
Does the pick-up move up and down twice?
Focus search OK.
Focus search
is performed
two times
when play
operation is
done without
disc.
0.5s
0.50 V
IC801 16 FD
2
1
0.5s
0.50 V
IC801 15 TD
Check the Focus - HF system.
Summary of Contents for QT-CD121
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