Power Supply Board - Kyocera FS-1050 - B/W Laser Printer Service Manual

(3) Power supply board

The power supply board provides the AC power input and DC power and outputs. The high voltage
bias generator circuit is mounted on a separate board. A simplified schematic diagram is shown
below.
Power
Current
AC
switch
fuse
input
(SW1) (F1)
Heater
lamp
Triac
(TRC1)
Thermal
cutout
Figure 4-3-8 Power supply board circuit block diagram
FS-1050
Power supply unit
Noise
filter
circuit
Transformer
(T1)
Switching/
FET
Over
(Q1)
current
detection
circuit
Photo-
coupler
(PC1)
Photo-
coupler
(PC3)
Photo-
Triac
(PC2)
4-26
24 V DC
24 V DC
rectifier/
shutoff
smooth-
circuit
ing circuit
5 V DC
rectifier/
smooth-
ing circuit
Over voltage
detection
circuit
Transistor
(Q8)
Zero cross signal
detection circuit
EXITN
Exit
sensor
+24 V COM
SLEEP
FAN
Cooling fan
+24 V COM
+5 V
PGND, SGND
THERM
Thermistor
+24 V
ZCROSS
HEAT