DOWNLOAD Panasonic UF-8300 / UF-8200 / UF-7300 / UF-7200 (serv.man2) Service Manual ↓ Size: 7.6 MB | Pages: 127 in PDF or view online for FREE

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

14

UF-7300/7200

UF-8300/8200

This circuit consists of the DC-DC Converter, which boosts +24V to approx. +5.4kV (constant current 
approx. +300

µA) for the Charge Corona. The nCHGCTL signal controls the charge output. If the signal 

goes Low, the output is turned On.

When the charge circuit is activated (nCHGCTL signal is Low), this circuit is activated and approx. 
+900V is generated on the Grid.

When the charge circuit is activated (nCHGCTL signal is low), this circuit is activated. 
This voltage varies between +100V and +500V in accordance with the PWM (Pulse Width Modulation) 
signal nDB when the signal nDBCH is Low. Also approx. - 150V is generated when signal nDB and 
nDBCH is High.

This circuit consists of the DC-DC Converter, which boosts +24V to -700V ~ -6000V (constant current). 
This current varies between -4µA and -20µA in accordance with the PWM (Pulse Width Modulation) 
signal nTR when the signal nTRCTL is High.

This circuit consists of a DC-DC converter, which boosts +24V to +1500V. 
This voltage is generated when signal nTR is High and nTRCTL is Low.

1. Do not attempt to repair this Power Supply Unit. This Power Supply requires proper calibration after 
    any component replacement. Failure to do so may result in component damage, shock fire or other 
    hazard.
2. High Voltage is present on the PC Board. Use caution when measuring voltage levels.

15

UF-7300/7200

UF-8300/8200

This machine has 2kbit EEPROM (IC502). Page Count Data, Calibration Data, etc. are saved on the IC.

The EEPROM control signals are explained as follows.

EEPCS :

This is the Chip select signal.

EEPCLK :

This is the Serial Data transfer clock.

EEPDO :

This is the Serial Data from CPU (IC504) to EEPROM (IC502).

EEPDI :

This is the Serial Data from EEPROM (IC502) to CPU (IC504).

CHGCTL

DBPWM

DBCH

TRPWM

TRCTL

7

10

CN728

5

6

3

4

2

8,9

nCHGCTL

+24VIR

nDB

nDBCH

nTR

nTRCTL

+5VA

GND (+24V)

7

10

CN501

5

6

3

4

2

8,9

Charge Control
Circuit

Transformer

Dev. Bias Control
Circuit

Transformer

Transformer

Transfer 
Control
Circuit

Transfer Roller 
Cleaning
Control Circuit

Transfer 

Dev. Bias

Charge

OPC

Grid 
Control
Circuit

Grid 

+24VIR

+24V

Right Cover

+5V

R540

R538

R539

8

54

9

58

10

IC504

Q503

Q502

Q505

Q506

L506

L509

L507

L508

L505

Q508

(Engine CPU)

Safety
Interlock SW

27

3 DI

IC502 (EEPROM)

IC504 (CPU)

EEPDO

EEPDO

33

4 DO

EEPDI

EEPDI

29

1 CS

EEPCS

EEPCS

28

2 SK

EEPCLK

EEPCLK

R518

R517

16

UF-7300/7200

UF-8300/8200

This machine has two safety interlock switches: So that the safety interlock works when the one side latch 
of the Right Cover is taken off. When the Right Cover is opened, the Safety Interlock Switch is opened and 
shuts Off the Main Motor Power and the High Voltage Unit Power and the +5V power for the Laser Diode. 
As a result, the signal at Pin17 of IC504 (Engine CPU) is changed from a low level to a high level. IC504 
(Engine CPU) receive this +24V power condition and turn Off the main motor control signal, the laser 
control signals, etc.

(Laser Diode Power)

Main Motor Power
High Voltage Unit Power 

(                                )

+24VA

Right Cover 

Safety 

Interlock SW

IC504

IC402

IC503

Q517

R544

R543

R542

+

+24VIR

L+5V

L+5V

L+5V

nDOPEN

P63

PPG01

NVIDEO

17

Q511

Q516

Q513

R512

R505

R502

R515

R525

R524

IN

OUT

COMMON

IC401

R409

L400

R526

nFSRCTL

R537

31

69

C418

+24VIR

Halogen

Lamp

Drive

Circuit

Laser

LVPS

LSU

Diode

(Engine CPU)

(ASIC)