Power Supply Board - Kyocera Mita KM-1500 Service Manual

2DC

2-3-3 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
2-3-8
Power supply unit
Noise
filter
circuit
Transformer
(T1)
Switching/
FET
Over
(Q1)
current
detection
circuit
Photo-
coupler
(PC1)
Photo-
coupler
(PC3)
Photo-
Triac
(PC2)
Figure 2-3-7 Power supply board circuit block diagram
Exit
sensor
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
+24V1
SLEEPN
FAN
Cooling fan
+24V1
+5 V
PGND, SGND
THERM
Thermistor
+24V2
ZCROSS
HEATN