Kyocera Mita DC-1560, Service Manual

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1AF
2-3-1
2-3-1 Composite PCB
Noise
filter
circuit
section
L1
AC
input
MSW
Switching
circuit IC1
TRNS
Rectify-
ing
circuit
D001
24 V DC
smooth-
ing/
output
circuit
D201/
C201/
C207
Output
feed-
back
circuit
5 V DC
smooth-
ing/
output
circuit
IC3
PC1 PC2
5 V DC
output
Power source
circuit section
Noise
filter
circuit
L001
H
HL
Halogen
lamp
light
intensity
control
IC
(HIC)
PT2
PC3
PWM
signal/
voltage
conver-
ter
circuit
PC4
TH
602
TH
601
Q602
PT1
AVR circuit section
24 V DC
output
HL CONT
H REM
SSW1
DH
C101
Q101
CPCB
Figure 2-3-1 Composite PCB block diagram
The composite PCB (CPCB) consists of three circuit sections: noise filter, power source and
AVR.
• Noise filter circuit section
The noise filter circuit consists of choke coil L1, a resistor and capacitor. These attenuate
external noise and prevent noise generated by the composite PCB (CPCB) and other
electrical components from escaping out of the copier via the AC line.
• Power source circuit section
The power source circuit section is a switching regulator which converts the AC input into
5 V and 24 V DC outputs. This section consists of the noise filter circuit, rectifying circuit,
switching circuit, 24 V DC smoothing/output circuit, 5 V DC smoothing/output circuit and
output feedback circuit.
The noise filter circuit consists of choke coil L001 and a capacitor. Any external noise that
has passed through the preceding noise filter circuit section is attenuated here, while the
switching noise generated in this section is prevented from escaping out via the AC line. The
AC input is full-wave rectified by diode bridge D001 and then smoothed by smoothing