Table of Contents
Advertisement
20 – Fuser Lamp Overheat
1. Check the I/O board.
a. Put the positive lead of the digital multimeter on pin 2 of IC33 on the I/O
b. Measure the voltage. If it is not 0V, go to Step 5.
2. Ensure that the fuser unit is installed properly.
3. Check the temperature fuse (LTF).
a. Remove connecting jack J22 from the I/O board CN22.
b. Measure the resistance between pins 3 and 4 on the side of the J22.
If resistance is not about 0Ω, replace the LTF after checking the harness.
4. Check the I/O board.
a. Short circuit pins 3 and 4 of CN22 on the I/O board.
b. Put the positive lead of the digital multimeter on pin 2 of IC33 on the I/O
c. Measure the voltage, which should be about 5V.
If voltage is not normal, replace the I/O board. If it is normal, go to Step 9.
5. Determine if the temperature is abnormally high (over 80 ). If it is, cool the fuser
unit and go to Step 6. Otherwise, go to Step 8.
6. Check the fuser reflector cooling fan (FCF). The cooling fan should run during
printing and for some time after printing stops, in order to continue cooling the
fuser unit. The fan then shuts off.
If the fan is working properly, go to Step 8. Otherwise, go to Step 7.
7–70
CHECKLIST:
FUSER UNIT
TEMPERATURE FUSE (LTF)
I/O BOARD
FUSER REFLECTOR COOLING FAN (FCF)
LAMP THERMISTOR (LTS)
board, and the negative lead on the SG.
board, and the negative lead on the SG.
Troubleshooting
Advertisement
Chapters
Table of Contents
