Power Supply Pwb - Kyocera KM-1820 Service Manual

2-3-3 Power supply PWB

The power supply PWB provides the AC power input and DC power and outputs. The high voltage bias generator circuit is
mounted on a separate PWB. A simplified schematic diagram is shown below.
Power Current
AC
switch fuse
input
(SW1) (F1)
Heater
lamp
(TRC1)
Thermal
cutout
Power supply unit
Noise
filter
circuit
Switching/
FET
Over
(Q1)
current
detection
circuit
Triac
Figure 2-3-9 Power supply PWB circuit block diagram
Transformer
(T1)
24 V DC
rectifier/
smooth-
ing circuit
5 V DC
rectifier/
smooth-
ing circuit
Photo-
Over voltage
coupler
detection
(PC1)
circuit
Photo-
Transistor
coupler
(Q8)
(PC3)
Zero cross signal
detection circuit
Photo-
Triac
(PC2)
EXITN
Exit
sensor
24 V DC
shutoff
circuit
2GM
+24V1
SLEEPN
FAN
Cooling fan
+24V1
+5 V
PGND, SGND
THERM
Thermistor
+24V2
ZCROSS
HEATN
2-3-17