Canon GP405 Service Manual page 517

53 The Close Front Cover message fails to turn off.
Cause
Front cover switch
DC controller
PCB (fuse)
If FU201 has blown,
• Check for wire trapping and make sure the harness shielding has not peeled.
1. Without removing the DC controller PCB from the copier (harness connected), check to make
sure that J105-1 and GND are shorted.
2. Connect the connectors from the DC controller PCB one at a time, and see if the meter reading
changes from 0 ½ upon each disconnection.
3. If the reading changes, the harness of the 5-VDC load leading to the connector that caused the
change is likely to be trapped or its harness shield may have peeled. (Correct the problem as by
covering the bare area to prevent direct contact with the stay. Be sure to check the 5-V line of
J106.)
4. If J105-1 and GND remain shorted when all connectors have been disconnected, replace the
DC controller PCB.
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Step Check
1 Is the front cover closed firmly?
CHAPTER 14 TROUBLESHOOTING
Yes/No
NO Check the switch lever
mechanism.
YES Replace the DC
controller PCB;
however, be sure to
perform the following in
advance:
• Check FU201 for
continuity; if there is
no continuity, see
below.
Action
14-99