Canon PC300 Service Manual page 56

&. Controlling the Scanning
Lamp
1. Quiline
Figure 3-24 shows the circuit that con-
trols the scanning lamp (fuse lamp:), and the
circuit has the following functions:
* Turns the scanning lamp ON and OFF.
* Controls the intensity of the scanning
lamp.
An intensity sensor (PD601) is provided
to ensure that the original will be illuminated
after the intensity of the scanning lamp has
stabilized.
Scanning lamp
OPERATIONS AND TIMING
The intensity of the scanning lamp is
checked by the lamp intensity detection sig-
nal (LID) to make sure that the intensity has
reached the specified value.
In addition, a rush current protection cir-
cuit is provided to prevent rush current
occurring when the lamp turns on.
Lamp intensity sensor signal (LID)
Q143
Lamp
ae
protection circuit
(LAPWM) |
Amplifier circuit
Control panel PCB
|
|
|
|
L
; DC controller/DC power supply PCB
Microprocessor
The number within parentheses represents the PC300/FC210.
Figure 3-24
COPYRIGHT © 1994. CANON INC.
CANON PC300/920325, FC2(0/230 REV.O JULY 1994 PRINTED IN JAPAN (IMPRIME AU JAPON) 3-29