Troubleshooting (Changer/Cd Section) - Sharp GX-CH170X Service Manual

TROUBLESHOOTING (CHANGER CONTROL SECTION)
When the changer mechanism fails to operate normally.
Operation failure may be caused by blocking of disc at the changer mechanism tray. Therefore, it is necessary to check at
first to see whether there is any disc blocking.
If no abnormal phenomena were found and the normal operation cannot be resumed, check as follows.
Set the FUNCTION switch to REMOTE ON mode, and set the POWER button to ON.
Set the FUNCTION switch to CD.
Does LCD give an indication?
Yes
Is the tray opened when the OPEN/CLOSE
button is pressed?
Yes
Does the CD mechanism move up and stop
when disc is selected?
Yes
Is "Er" displayed after normal stop?
No
Normal
• CD microcomputer operation failure.
Is +5V applied to the pin 7 of FW751?
Yes
Is +5V applied to the pin 25 (VDD) of IC901?
Yes
Is the oscillation circuit (periphery of XL701)
of IC901 normal?
Yes
Does LCD display appears when the pin 21
(RESET) of IC901 is instantaneously
connected to GND
Yes
Does the LCD indication change in the LCD
TEST mode?
Yes
Normal
Check as stated in item "CD MICROCOMPUTER OPERATION FAILURE".
No
Check as stated in item "THE DISC TRAY CANNOT BE OPENED AND CLOSED".
No
Check as stated in item "DISC CHANGE FAILURE".
No
Check the optical pickup IN switch. (SW702)
Yes
Check for contact failure of Flexible wire. If OK, check the main PWB side power
No
line.
Check the pattern between FW751 and the pin 25 of IC901.
No
XL701 or IC901 is faulty.
No
Check the reset line.
No
Check voltage on the pins 41, 42, 43, and 44 of IC901. If OK, IC951 or LCD801 is
No
faulty.
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GX-CH170X/CH170Z