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Service Guide ML520/521
Chapter 4 Failure & Repair Analysis
RAP 02 No Spacing Operation
START
The alarm LED blinks.
Is the carriage assembly binding or jammed?
No Make sure the carriage cable is properly connected to the space motor assembly and CN7 on the
main control board.
Go to A.
Yes 1. Remove the ribbon to verify that the ribbon is not jammed.
2. Remove the space motor assembly
3. Inspect the teeth on the space rack and the space motor gear.
4. Go to A.
A
Has the problem been resolved?
Yes End of procedure.
No Is the fuse F2 on the main control board open?
No Go to B.
Yes Replace the main control board.
Has the problem been resolved?
Yes End of procedure.
No Go to B.
B
Verify that +40 volts is present on CN7 main control board (Refer to Appendix A of the Service
Handbook).
Has the problem been resolved?
Yes End of procedure.
No Replace the carriage cable.
Has the problem been resolved?
Yes End of procedure.
No Replace the ribbon feed mechanism
Has the problem been resolved?
Yes End of procedure.
No Replace the PROM (O5CA)
