Ricoh FT8680 Service Manual page 377

31 July 1995
SC440 - Main Motor Overload
Definition:
The motor control PCB cannot maintain the motor speed within the
specification for more than 1 second, or the motor control PCB detects a
large current (8 A) at the main motor for more than 2 seconds.
Points to check:
•
Mechanical interference with the main motor
•
Main motor and encoder
•
Motor control PCB
•
Front door safety switch
•
1st tray unit set switch
•
DC motor drive PCB (Fuse: F2)
SC442 - Drum Thermistor Open
Definition:
The Main PCB detects an extremely low temperature (–10°C) by the drum
thermistor for more than 3 seconds.
NOTE: The main relays will be opened in this condition.
Points to check:
•
Drum thermistor
•
Main PCB (CN104-A4)
SC443 - High Drum Temperature
Definition:
The main PCB detects an extremely high temperature (60°C) by the drum
thermistor for more than 3 seconds.
NOTE: 1. The main relays will be opened in this condition.
2. No detection in copy mode.
Points to check:
•
Drum thermistor (short circuit)
•
Drum heater
•
Main PCB (CN104-A4)
SYSTEM ERROR AND SERVICE CALL CONDITIONS
6-15