Sharp GX-CH170X Service Manual page 12

GX-CH170X/CH170Z
• The disc tray cannot be opened and closed.
Is +7.4V applied to the pin 6 of IC761?
Yes
Does the LCD "?" indication rotate when the main unit
or remote control OPEN/CLOSE button is pressed?
Yes
Check that the pin 64 of IC901 is in Low state but the pin
1 is in High state when the OPEN/CLOSE button is
pressed. (Tray 1 unloading) (Tray 2 unloading: Pin 64
High, pin 1 Low)
Yes
Check that +6V is output to the pin 9 in Tray1 mode and
that +6V is output to the pin 7 in Tray2 mode.
Yes
Is about +6V output between pins 4 and 5 of CNP753?
Yes
Is about +6V applied to the loading motor M981C?
Yes
Check the loading motor M981C and loading
mechanism.
IC901
Pin 1 Pin64
Tray1 Open H L
Tray2 Open L H
Tray1 Close L H
Tray2 Close H L
• Disc change failure.
Is +7.4V applied to the pin 6 of IC761?
Does the LCD "?" indication rotate when the main unit
or remote control DISC CHANGE button is pressed?
Yes
Disc move failure?
Operation
failure
Check that the IC901 pin voltage is as follows:
Pin 1
Disc2 -> Disc1 L
Disc1 -> Disc2 H
Yes
Check that the IC761 pin voltage is as follows:
Pin 7
Disc1 -> Disc2 0
Disc2 -> Disc1 +6V
Yes
Is voltage applied to the loading motor M781C?
Yes
The motor M981C is defective.
No
No
No
No
No
No
M981C
IC761
Motor
operation
Pin 9
Pin 7
0 +6V Reverse
+6V 0 Forward
+6V 0 Forward
0 +6V Reverse
No
Remains
persistently.
No
Pin 64
H
L
No
Pin 9
+6V
0
No
Check the +7.5V power line.
Check the main unit button or remote control.
Check IC901.
IC761 is defective.
Check the pattern between IC761 and CNP753.
Check for breakage of connecting wire for loading motor M981C.
Check the main unit button or remote control.
Check the changer mechanism switches.
IC901 is defective.
IC761 is defective. Or check the pattern between pin 64 of IC901 and
pin 1 of IC761, the pattern between pin 1 of IC901 and pin 3 of IC761.
Check for breakage of wire CNW753 to loading motor M981C.
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