Protective Functions; Low-Voltage Power Supply Circuit; Protective Function - Canon LBP3300 Series Service Manual

Noise
filter
Rectification
circuit
Regulator
Overcurrent
protection circuit

2.6.2.2 Protective Functions

2.6.2.2.1 Protective function

The low-voltage power supply circuit utilizes the overcurrent protective function to prevent the power supply circuit failure. It automatically interrupts the output
voltage when the overcurrent occurs due to a short-circuit at the load side.
If the overcurrent protective function is activated and the DC voltage is not output from this circuit, be sure to turn the printer OFF, rectify the problem at the faulty
loads and then turn the printer ON again.
Be sure to wait for more than approx. 2 min. to turn the printer ON again from when the power is turned OFF.
This circuit contains the fuse 1 (FU101) and the fuse 2 (FU102: 110-127V only). The fuses burn and interrupt the power supply if the overcurrent flows in the AC
line.
Power switch
(SW101)
Low-voltage power
supply circuit
Fuse
(FU101)
Noise
filter
Fuse (FU102)
110-127V only
Transformer
(T501)
+24V
power
supply
circuit
+5V
power
supply
circuit
+3.3V
power
supply
circuit
Engine control PCB
Relay
Triac
(RL101)
Fixing heater
safety circuit
High-voltage
power supply
CPU
(IC201)
Fan motor
drive circuit
+24V
+5V
+3.3V
F-2-23
ACN
Fixing heater
ACH
circuit
Door switch
(SW301)
Fan motor
Main motor
Solenoids
Option
(DaVinci only)
Video controller
PCB
Laser/scanner
unit
Sensors
Chapter 2
+24U
0011-2505
2-19