Canon NP6621 Service Handbook page 79

26 The pre-exposure lamp fails to turn ON.
Cause Step
DC control- 1 Remove the drum cartridge, and
ler PCB execute service mode No. 411. Does
the pre-exposure lamp turn ON
normally?
Pre-expo- 2 Replace the pre-exposure lamp. Does
sure lamp it turn ON normally?
DC control-
ler PCB
27 The ADD PAPER message fails to turn OFF.
Cause Step
Cassette 1 Is the cassette set correctly?
Paper 2 Are the following sensors normal?
sensor PS14:
PS13:
PS2cu: cassette 3 paper sensor (accessory)
DC control- PS4cu: cassette 4 paper sensor (accessory)
ler PCB PS7cu: cassette 5 paper sensor (accessory)
PS2:
28 The JAM message fails to turn OFF.
Cause Step
Jam 1 Find out which sensor detected the
jam using service mode 107 (jam
history). Is there paper around the
sensor?
Sensor 2 Is the sensor identified in step 1
normal?
DC control-
ler PCB
Checks
Checks
cassette 1 paper sensor
cassette 2 paper sensor
paper deck
Checks
TROUBLESHOOTING MALFUNCTIONS
Yes/No Remedy
NO Replace the pre-exposure
lamp.
YES End.
NO Check the wiring from the
pre-exposure lamp to the DC
controller PCB; if normal,
replace the DC controller
PCB.
Yes/No Remedy
NO Set the cassette correctly.
NO Check the lever and the
wiring; if normal, replace the
sensor.
YES Replace the DC controller
PCB.
Yes/No Remedy
YES Remove it.
NO Check the lever and the
wiring; if normal, replace the
sensor.
YES Replace the DC controller
PCB.
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