UF-8300, UF-8200, UF-7300, UF-7200 (serv.man2) - Panasonic Fax Other Service Manuals (repair manual). Page 13

13

UF-7300/7200

UF-8300/8200

The fuser temperature is controlled by IC504 (Engine CPU). IC504 has an analog to digital (A/D) converter 
(AN0-AN7).
Thermistor TH is connected to IC504 (AN0). When IC504 (Pin31) is Low, Q516 is turned Off. And Q513 is 
turned On. Then Halogen Lamp in Fuser Unit is turned On.
When Right Cover is opened, the Right Cover Safety Interlock Switch is opened and the Halogen Lamp is 
turned Off.

Abnormal temperature detection circuit consists of the following 2 sub-sections.

1. Abnormally Low Temperature Detection

When abnormally low temperature is detected by IC504 (Engine CPU), the IC504 turns Off the 
Halogen Lamp.

 

When the Thermistor is open, abnormally Low temperature is detected. And the 

protect circuit which consist of Q501, Q507 and Q512 works, and Halogen Lamp is turned Off.

2. Abnormally High Temperature Detection

When abnormally high temperature is detected by IC504 (Engine CPU), the IC504 turns Off the 
Halogen Lamp. If the Halogen Lamp is not turned Off by IC504 though the temperature of Halogen 
Lamp is abnormally high, the IC505 turns Off the Halogen Lamp electrically.

C546

C547

R536

R548

+24VA

TH

Right Cover 

Safety 

Interlock SW

GND (+5V)

GND (+24V)

THERMISTOR

IC504

P63

AN0

3

nFSRCTL

R537

PPG01

31

Q516

R515

+24VIR

Q513

nFCTL

Halogen

Lamp

Drive

Circuit

LVPS

Unit

R509

R510

3
2

1

+

-

IC505

L512

Q517

R505

D501

L511

nDOPEN

17

R544

R543

R542

+

(Engine CPU)

Q501

Q512

Q507

R504

R503

R508

R507

Q511

R512

R502

+24VIR