Oki OL1200 Service Manual page 155

YES END.
Is the operator panel connected to the Control board properly?
No
Yes Is the connecting cord defective?
Yes
No Replace the operator panel assembly.
Is the printer recovered?
No
YES END.
Yes Is
No Replace the Control board.
YES
No Take the proper action following the message shown in the LCD display.
(For details, see the chapter 6.5.1 LCD STATUS message/trouble list.)
YES END.
No Replace the Main board
Connect the operator panel properly.
Replace the connecting cord.
Replace the Control board.
message shown in the LCD display?
message shown in the LCD display?