Canon LBP-2000 Service Manual page 56

5. Detecting a fault in the fixing assembly
The CPU will identify a fault in the fixing assembly under any of the following conditions (a through
e) and execute the following:
1) Causes the /FSRDRV signal to go High to cut the power to the fixing heater.
2) Causes the RLYDRV signal to go Low to turn off RL1 while at the same time communicating
the presence of a fault to the video controller PCB, thereby indicating any of the following on
the LCD in the control panel: 'E000', 'E001', 'E003', 'E808'.
Caution: If 'E000', 'E001', 'E003' or 'E808' is indicated, the information on the fault in the fixing
assembly is retained in the NVRAM on the DC controller PCB even after the power
switch has been turned off and then on. (Whether or not the code is indicated depends
on the reading of the fixing roller temperature.) If the code is indicated, be sure to clear
the fault information using service mode.
(See C. of VIII. in Chapter 1.)
a. Detecting a fault at power-up
• the main thermistor reading does not reach 60°C within 10 sec after it has exceeded 40°C
• the main thermistor reading does not reach 80°C within 10 sec after it has exceeded 60°C
• the main thermistor reading does not reach 100°C within 10 sec after it has exceeded 80°C
• the main thermistor reading does not reach 120°C within 10 sec after it has exceeded 100°C
• the main thermistor reading does not reach 140°C within 10 sec after it has exceeded 120°C
• the main thermistor reading does not reach 160°C within 10 sec after it has exceeded 140°C
• the main thermistor reading does not reach 180°C within 10 sec after it has exceeded 160°C
• the main thermistor reading does not reach 195°C within 10 sec after it has exceeded 180°C
b. Detecting an abnormally low temperature
• the main thermistor reading does not each 40°C within 14 sec after the fixing heater has been
turned on
c. Detecting an abnormally low temperature during temperature control
• the main thermistor reading drops below 100°C after the end of wait state
• the sub thermistor reading is 50°C or lower during standby
d. Detecting overheating
• the main thermistor reading is 220°C or higher
e. Detecting a fault in the drive circuit
• the /ZEROXI signal cycle of the power supply cannot be detected during initialization
• the /ZEROXI signal does not arrive for 3 sec continuously during temperature control
• a short circuit is detected in the triac by the ASIC
CHAPTER 2
2 - 17