Oki OKIOFFICE84 Maintenance Manual page 468

12: Operation interface
does not operate correctly
Pin 77 of IC2 remains
at 0V
No
Pin 79 of IC2 remains at
0V or 5V
No
Pin 1 of CN4 changes to
0V or 5V when the operation
panel key is pressed
Yes
Pin 2 of CN4 changes to
0V or 5V when the operation
panel keys are pressed
No
Check CN4 connection.
Yes
Yes
Pin 5 of IC15 remains at
0V or 5V
Replace IC15.
No
Inputs of pins 11 and 13
of IC15 change to 0V or 5V
when the operation panel
key is pressed
Replace IC15.
Yes
11 Output waveforms of pins
2 and 4 of IC15 change to
0V or 5V when the operation
panel key is pressed
Replace IC15.
H - 13
Yes
No
Check CN4
connection.
No
Yes
Yes
No
Replace IC2.
40672201TH Rev. 4