Panasonic KX-MB1900UCB / KX-MB2020UCB (serv.man2) Service Manual ▷ View online
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KX-MB1900UCB/KX-MB2020UCB
wave form
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KX-MB1900UCB/KX-MB2020UCB
6.18. Power Supply Board Section
The power supply board circuit generates +7V and +24Vdc. It also supplies AC voltage to the halogen heat lamp in the fuser
unit. The power supply board uses the switching regulator method.
unit. The power supply board uses the switching regulator method.
[Input Circuit]
The input current goes into the input rectifier circuit through the filter circuit.
The filter circuit decreases the noise voltage and the noise electric field strength.
The filter circuit decreases the noise voltage and the noise electric field strength.
[Rectifier Circuit]
The input circuit is rectified by D1 and charge C5 to make DC voltage.
Then it supplies power to the converter circuit.
Then it supplies power to the converter circuit.
[Kick-on Voltage Circuit]
Bias is applied to the Q1 gate via this circuit when the AC power is turned on and Q1 begins operating.
[Over Current Limiter (O.C.L)]
The highest drain current of Q1 is limited by a limit current circuit. The 24V output is limited by this circuit.
[Over Voltage Circuit]
If the 24V output increases because the error detecting circuit or control circuit is broken.
Control circuit will recognize this signal and output becomes 0V. D104 and D503 also prevent over voltage.
Control circuit will recognize this signal and output becomes 0V. D104 and D503 also prevent over voltage.
Dummy load method (to quickly check the power supply output)
Refer to Power Supply Board Section (P.190)
Input
Circuit
Circuit
AC
Input
Input
C5
G
H
24V
Kick-on
Voltage
Circuit
Voltage
Circuit
E
F
7V
HTRCTL
GND
Control
Circuit
Circuit
R4
R3
R2
Converter
Circuit
Circuit
C
D
Rectifier
Circuit
Circuit
A
B
+
Error Detecting
Circuit
Circuit
O.C.L
Q1
A-B Voltage Wave Form
C-D Voltage Wave Form
E-F
G-H Voltage Wave Form
0
0
0
T1
PC1
Triac
SCR51
SCR51
Heat Lamp
Photo Triac
Coupler PC2
Coupler PC2
Block Diagram
+
+
F101
R41
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KX-MB1900UCB/KX-MB2020UCB
6.19. Mechanical Operation
6.19.1. Printing
The main motor gear rotates as shown in figure.
GEAR DRIVE OPC drives each part of fixing and developing.
When paper is fed from the standard cassette, the plunger of solenoid is pulled to drive PICK UP ROLLER (STANDARD), then
the roller starts feeding paper.
When paper is fed manually, first the plunger of solenoid is pulled to stop REGISTRATION ROLLER. After a few moments turn
off the solenoid to drive REGISTRATION ROLLER, then the roller starts feeding paper.
GEAR DRIVE OPC drives each part of fixing and developing.
When paper is fed from the standard cassette, the plunger of solenoid is pulled to drive PICK UP ROLLER (STANDARD), then
the roller starts feeding paper.
When paper is fed manually, first the plunger of solenoid is pulled to stop REGISTRATION ROLLER. After a few moments turn
off the solenoid to drive REGISTRATION ROLLER, then the roller starts feeding paper.
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KX-MB1900UCB/KX-MB2020UCB
7 Location of Controls and Components
7.1.
Overview
7.1.1.
Front view
(1) Top cover
(2) Document cover
(3) Power Switch
(4) Output tray
(5) Paper input tray
(6) Recording paper exit
(7) Speaker (KX-MB2020 only)
(8) Handset unit connection jack (KX-MB2020 only)
(2) Document cover
(3) Power Switch
(4) Output tray
(5) Paper input tray
(6) Recording paper exit
(7) Speaker (KX-MB2020 only)
(8) Handset unit connection jack (KX-MB2020 only)
7.1.2.
Rear view
(1) Recording paper guides
(2) LED (KX-MB2020 only)
(3) LAN interface connector (KX-MB2020 only)
(2) LED (KX-MB2020 only)
(3) LAN interface connector (KX-MB2020 only)
• 10Base-T/100Base-TX
(4) Power inlet
(5) Manual input tray (Rear cover)
(6) External telephone jack (KX-MB2020 only)
(7) Telephone line jack (KX-MB2020 only)
(8) USB interface connector
(5) Manual input tray (Rear cover)
(6) External telephone jack (KX-MB2020 only)
(7) Telephone line jack (KX-MB2020 only)
(8) USB interface connector
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