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Service Guide ML320/ML321
Chapter 4 Failure & Repair Analysis
RAP 01B:Operator Panel Lamps Do Not Light - Rev D
START
Are the AC cables connected correctly?
NO
Connect the AC cables correctly.
Is the problem resolved?
YES
End of procedure.
NO
Go to A
YES
Go to A
A
Check the AC fuse on the primary side of the filter assembly. Is it open?
YES
Replace the fuse
Is the problem resolved?
YES
End of procedure.
NO
Go to B
NO
Go to B
B
Verify that the fuse holder is making proper contact with the fuse. Remove the fuse from
the holder. Gently squeeze both sides of the holder slightly towards each other. Reinsert
the fuse. Is the problem resolved?
YES
End of procedure.
NO
Are + 5 vdc and + 50 vdc supplied to the control board?
+ 5 vdc
Take the voltage reading between Pin 16 and Pin 34 of the
IC4 (ROM) on the control board.
+ 50 vdc
Take the voltage reading between both leads of C33 on the
control board. Meter should read + 50 vdc.
