Samsung ML-1755, Service Manual, Page: 30 / 116

4-19
Samsung Electronics
S U M M A RY OF PRO D U C T
Training Manual
Error Description DCU LED Displat
Open heat error When warming up, it has been lower 60 All LED are flashing.
than 68°C over 28 seconds
Lower heat error • Standby: 62 All LED are flashing
It has been lower than 80°C over 10 seconds
• Printing:
- 2 consecutive pages: it has been lower than
145°C over 4 seconds.
- 3 consecutive page; it has been 25°C lower
than the fixed fusing temperature over 4 seconds.
Over heat error It have been higher than 220°C over 3 seconds 68 All LED are flashing
Error Description DCU LED Displat
Open heat error When preheating, it has been lower than 68°C 60 All LED are flashing
over 15 seconds.
Lower heat error • After finishing the preheating stage, 62 All LED are flashing
it has not reached 100°C (preheating stop
temperature) during 15 seconds since the
temperature is over 68°C.
• Printing
1) When the main motor is on and after 0.92
second, it has not reached the 160°C
during 20 seconds.
2) From the 2 consecutive pages, it has been
20°C lower than the fusing temperature
over 4 seconds.
Over heat error • the error is not displayed immediately when 68 All LED are flashing
it has been over 220°C over 3 seconds.
The temperature after the 3 seconds is checked.
If it is over 240°C, it is error.
• If the temperature has been higher than 220°C
over 25 seconds, it is an error even through the
temperature doesn’t reach 240°C.
4.6.4 Fusing
The temperature change of the heat roller’s surface is changed to the resistance value through the thermis-
tor. By converting the voltage value, which impressed to the resistance, to the digital value through the AD
converter, the temperature is decided. The AC power is controlled by comparing the target temperature to
the value from the thermistor. If the value from the thermistor is out of the controlling range while control-
ling the fusing, the error stated in the table occurs. (For the domestic model, the Q-PID method has been
applied.)
4.6.4.1 Heat Lamp Method
4.6.4.2 Q-PID Method