Canon GP335 Service Manual page 516

CHAPTER 14 TROUBLESHOOTING
51 The Add Toner message fails to turn off.
Cause
Stirring spring
Toner sensor
DC controller
PCB
52 The fax error indicator lamp fails to turn off.
Cause
Paper
Fax
Image processor
PCB
Fax PCB
14-98
Step Check
1 Remove the developing assembly.
Is the stirring spring used to agitate
toner around the toner sensor (TS1)
mounted correctly?
2 Is the reading of I/O>DC-
CON>P003-bit3 '0' even after toner
has been supplied?
Step Check
1 Is there paper in all cassettes in the
machine?
2 Is fax transmission/reception
normal?
2 Does FUNCTION>MISC-P>IP-
CHK end in 'OK'?
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Yes/No Action
NO Correct the mounting.
NO Replace the toner
sensor.
YES Replace the DC
controller PCB.
Yes/No Action
NO Supply the cassettes
with paper. Inform the
user that the presence of
a cassette without paper
will cause the fax error
lamp to flash.
NO Check the wiring to the
telephone line.
NO Replace the image
processor PCB.
YES Check the wiring of the
PCB; if normal, replace
the fax PCB.