KYOCERA FS-1010 User Manual download pdf (Page 72)

4-21

FS-1010

Eraser lamp control circuit

The CPU (U01) turns pin #23 (ERASERN) of U01 to H level, transistors (Q16 and Q14) turns on

consequently, and the 24 V DC given at pin #1 of connector YC05 applies to the eraser lamps. The

eraser lamps thus illuminate as the current flows through the eraser lamp, the pin #2 of connector

YC05, resistors (R75/R76, and R77/R78), and the ground.

Pin #27 (ERRDYN) of the CPU (U01) is wired to the crossing of resistors (R75/R26 and R77/R78)

via resistor (R74). The U01 turns pin #23 (ERASERN) to H level and monitors the input level after

one second. If the eraser lamp is normal, the current flowing through R74 also flows the zener

diode (DZ01), making the voltage at pin #27 to be approximately 3.7 V. On the contrary, if the level

at pin #27 (ERRDYN) is less than 1 V for more than 2 seconds, despite the U01 turns pin #23

(ERASERN) to H level and applying the 24 V DC to pin #1 of connector YC05, the U01 recognizes

that the current is not flowing through the eraser lamp. The LED indicator “Call service

5300” error is then displayed.

Figure 4-3-4 Eraser lamp control circuit

R69

R74

R68

GND

PGND

GND

Q14

ERRDYN

R75 R76

R77

R78

DZ01

Q16

ERASERN

+24V

ERASPW

C33

Eraser lamp

YC05

P16/ANI6

P25/ASCK0

CPU

U01

ERASER

Engine board

Eraser lamp cotrol circuit

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KYOCERA FS-1010 User Manual Page 72