Canon NP6320 Service Manual page 228

CHAPTER 10 TROUBLESHOOTING
20. Pre-exposure lamp does not light
Cause Step
Pre-exposure 1
lamp PCB
DC controller
PCB
21. Scanning lamp does not light
Cause Step
Lamp 1
Thermal fuse 2
(FU2)
Broken lamp 3
filament
DC controller 4
PCB
Lamp 5
driver PCB
Wiring
10-50
COPYRIGHT © 1999 CANON INC.
Checks
Disconnect J304 from the DC controller
PCB. Set the meter to the 1Ω range. Con-
nect the leads to J304-5 and J304-6 of the
part of J304 connected to the wiring. Is the
resistance approx. 9Ω?
Checks
Is the lamp installed correctly?
Check the continuity of the thermal fuse
(FU2). (Connect the leads to both ends of
the fuse). Is there continuity?
Disconnect connector J602 (2P) from the
lamp regulator.
Set the meter to the 1kΩ range. Connect
the leads to the lamp terminals. Does the
needle move?
Set the meter to the 50VDC range. Con-
nect the (+) lead to J305-4 and the (−) lead
to J305-2; then, press the Copy Start key.
Does the voltage change from about 15V
to about 0V when the lamp goes ON?
Does the lamp go ON where the lamp
driver PCB is replaced?
CANON NP6320 REV.0 DEC. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
YES/
Action
NO
NO Replace the pre-exposure
lamp PCB.
YES Replace the DC control-
ler PCB.
YES/
Action
NO
NO Re-installed the lamp.
NO Replace the thermal fuse
(FU2).
Note:
There may be trouble
with the lamp not light-
ing normally, the fuse
being installed in the
wrong position, or the
cooling fan not operat-
ing, so be sure to check
operation after replacing
the fuse.
NO Replace the lamp.
NO Replace the DC control-
ler PCB.
YES End.
NO Check the AC wiring
from the power switch to
the lamp driver and
lamp, and check the DC
wiring from the DC con-
troller to the lamp driver.