Canon FAX-L260i Service Manual page 54

FAX-L260i Chapter 1: General Description
5.5 Protective Mechanism
5.5.1 Data battery backup function
If there is a power outage or if the power is turned off, the data stored in the control memory is retained since
the lithium battery function as a data battery backup.
REFERENCE
5.5.2 Overcurrent protection
This machine is provided with an overcurrent with built-in fuse, to prevent abnormal rises in temperature if
an overcurrent flows to the motors and power supply due to driver IC trouble, software lockup and short
circuit.
Protected Parts
Document feed motor
Main motor
Power supply unit
Fixing ass'y
5.5.3 Lightning protection
The fax unit's electrical components are protected from abnormal voltage caused by lightning.
Protected Component
Power supply unit
G4 board ass'y
NOTE
5.5.4 Power leakage protection
The AC line, ISDN line, and metal parts of the fax unit are completely insulated. The fax unit has a grounded
power cord to prevent electrical shock. If power leakage does occur, use the fax unit only with a grounded
electrical outlet supplying the proper voltage.
For details on the backed up data, see Chapter 1: 5.4 Data related precautions on Page
1-34.
Safety Measures
IC protector (FU401) on PCNT board
IC protector (FU401) on PCNT board
Glass-tube current fuse (FU101 : 250V)
overcurrent protection circuit
thermistor (TH101)
Thermal fuse, thermistor
Safety Device
Varistor (VZ101) located at the primary side of the power supply
unit discharge a voltage of more than
The arrester (VZ1~4) positioned on the primary side of the G4 board
discharges via the ISDN line more than 1000V of voltage applied between
the line and the line. More than 500V applied between the line and the GND
is also discharged via the power cord.
When protection is not possible
The G4 board sometimes may not be protected even by the protection circuits if lightning
strikes the ISDN line.
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