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Service Guide ML520/521
Chapter 4 Failure & Repair Analysis
RAP 03 Printhead Homing Error
START
Printhead does not return to the home position.
Make sure the carriage cable is properly connected to the space motor assembly and CN8 on the main
control board.
Make sure the power connector cable is properly connected to CN3 on the main control board.
Does the space motor assembly move manually?
No Remove the space motor assembly and inspect the space motor and space rack for dirt and worn
teeth.
Go to A
Yes Are there any breaks in the carriage cable?
Yes Replace the carriage cable assembly.
Go to A
No Verify that ribbon feed mechanism is properly fastened to the space motor assembly.
Go to A
A
Does the carriage move slightly to the left after turning the power on?
No Replace the space motor assembly.
Has the problem been resolved?
Yes End of procedure.
No Contact Technical Support.
Yes Replace the ribbon feed assembly.
Has the problem been resolved?
Yes End of procedure.
No Replace the main control board.
Has the problem been resolved?
Yes End of procedure.
No Replace the space motor assembly.
Has the problem been resolved?
Yes End of procedure.
No Contact Technical Support.
