Panasonic UF-580 Service Manual page 213

Fuser Temperature Control Circuit
The fuser temperature is controlled by IC1 on the SC PC Board, which contains A/D (Analog/Digital)
converters ANI0 to ANI7. The Fuser Temperature Control Circuit uses A/D converter, ANI1. When the
PC001 drive current is transmitted from the SC PC Board to the PSU (LVPS), the Fuser Lamp turns ON.
IC32 is a comparator with open output at pins 1 and 7 and is used as an abnormal temperature detection
circuit. IC32, pin 7, has a high impedance when Q44 is activated, turning ON the Fuser Lamp.
An abnormal temperature is detected when the VTH voltage level becomes higher than V+, forcing IC32,
pin 7 Low and deactivating Q44.
Abnormally low and high temperatures, as well as Thermistor release status, are detected by IC1 (CPU)
programming.
CN52
2
1
Thermistor
IC3
SHINE
R401
pSSRA
+3.3V
D26
+3.3V
TH2
D25
+5v
GND
79
(ANI1)
IC1
C263
CPU
GND
Fuser Temperature Control Circuit Diagram
3
2
Q44
1
GND
+24V
R396
5 8
7
6
IC32
4
GND
+3.3V
2
Q42
3
2
1
GND
TH2
R395
SC PCB
213
+24v
CN6 CN103
11
11
PSU (LVPS)
3
Q43
1
PC001
6
1
2
4