Canon LBP5050 Series, Service Manual

Page: 41 / 104

Chapter 2
2-15
F-2-20
The low-voltage power supply activates when the AC power is supplied through the fixing power supply by plugging in the AC power cord and turning on the
power switch. The AC power is converted into +24V and +3.3V in the low-voltage power supply to serve the DC power load requirement.
2.7.1.2 Other Function
2.7.1.2.1 Protective function
0018-6516
LBP5050N / LBP5050
The low-voltage power supply has a protective function against overcurrent and overvoltage to prevent failures in the power supply circuit. If there flows an over-
current or overvoltage, the low-voltage system automatically cuts off the output voltage.
If the DC voltage is not being supplied from the low-voltage power supply, turn off the power switch and unplug the AC power cord. Do not turn the power switch
on again until the root cause is found.
In addition, two fuses in the fixing power supply protect against overcurrent. If overcurrent flows into the AC line, the fuses blow and cut off the AC power.
2.7.1.2.2 Power-save mode
0018-6517
LBP5050N / LBP5050
The power-save mode reduces power consumption of the printer.
When the low-voltage power supply receives the POWER SAVE (REM24V) signal from the DC controller, it stops the power supply from the +24V generation
circuit.
2.8 ENGINE CONTROL SYSTEM
2.8.1 DC Controller
2.8.1.1 Outline
0018-6313
LBP5050N / LBP5050
+3.3V
+24V
FREQSNS
REM24V
DC controller
Protection circuit
Low-voltage power supply
Fuse
FU901
Noise filter
Rectifying
circuit
Fixing
control circuit
+24V
generation
circuit
+3.3V
generation
circuit
Frequency
detection circuit
Power switch
SW801
AC input
Only for the 200V model
Noise filter
Fixing power supply
Fuse
FU801