The Scanning Lamp Fails To Turn On - Canon 1000 Service Manual

38

The scanning lamp fails to turn ON.

Cause Step
Lamp
Thermal switch
Lamp (open
circuit)
Lamp regulator
overcurrent
AC power
supply
DC power
supply PCB
Lamp regulator
PCB
Reader unit
controller PCB
COPYRIGHT © 2001 CANON INC.
Checks
1 Turn OFF the power switch, and
disconnect the power plug. Is the
lamp installed properly?
2 Check both terminals of the thermal
switch for electrical continuity using
the meter. Is there continuity?
3 Disconnect J135 (3P) on the lamp
regulator, and set the meter to the
1kΩ range. Does the index of the
meter swing when the probe is
connected to the connector on the
harness side?
4 Is there electrical continuity on the
fuse on the lamp regulator?
5 Connect J135, and disconnect J131
(4P). Connect the power plug, and
turn ON the power switch. Set the
meter to the 300VAC range, and
measure the voltage between J131-
1 and 4 on the harness side. Is the
rated voltage present?
6 Turn OFF the power switch, and
connect J131. Set the meter to the
50VEDC range, and turn ON the
power switch. Is 24 VDC present
between J6230-2 (+; 24 V) and
J6230-1 (–; GND)?
7 Set the meter to the 50VDC range,
and connect the probes to J6230-4
(+; LAON*) and J6230-1 (–; GND)
on the lamp regulator PCB. Does
the voltage change from about 24 V
to about 0 V when the Start key is
pressed?
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
7. TROUBLESHOOTING IMAGE FAULTS/MALFUNCTIONS
Yes/No
NO
NO
NO
NO
NO
NO
YES
NO
Action
Re-install the lamp.
Replace the thermal
switch.
• The lamp may have
turned on wrongly, the
thermal switch may
have been mounted
wrongly, or the cooling
fan may have failed to
operate. Make checks.
Check the wiring from
J135 to the lamp; if
normal, replace the lamp.
Replace the lamp regula-
tor.
• Check the lamp and the
harness for a short
circuit.
See "AC power is absent."
See "DC power is ab-
sent."
Replace the lamp regula-
tor PCB.
Check the wiring from
J6230 to J1305 on the
reader unit controller
PCB; if normal, replace
the image processor PCB.
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