Canon FAX-L1000 - Manual (Page 52)

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FAX-L1000 Chapter 1: Safety and Precautions
4.3 Built-in Safety Measures
4.3.1 Overcurrent protection
This fax is provided with an overcurrent protection circuit with built-in current fuse and
thermal 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 circuits.
Protected Parts Safety Measures
Document read motor IC protector (FU2) on SCNT board
Stamp unit (option) Current fuse (FU1) on SCNT board
Power supply unit Glass-tube current fuse (F1 (125V, 15A), F2 (125V,
6.3A)), overcurrent protection circuit
Fixing heater Thermal fuse (446°F/230°C), thermistor
4.3.2 Lightning protection
This fax is provided with a function for protecting electronic components from abnormal
voltage caused by lightning.
Protected Parts Safety Measures
NCU board ass’y Arrestors (AR1, AR2) located at the primary side
of the NCU board discharge a voltage of more than
DC 320 to 350V via the telephone line or the power
cord.
Power supply unit Surge-absorber (NR3) located at the primary side
of the power supply unit goes into short-mode at a
voltage of more than 423V, and breaks. After this,
the glass-tube current fuse F2 or F1 blows.
NOTE
When protection is not possible
The NCU board sometimes may not be protected even by the protection
circuits if lightning strikes the telephone line.