Ricoh FT7770 Service Manual page 565

Service Call 2 - Drum Thermistor
o The drum thermistor circuit opens.
o Turn the main switch off.
o Remove the drum thermistor unit.
Is the drum thermistor open circuit?
N
o
Set the drum thermistor unit.
o Disconnect CN202 on the main board.
Is there an open circuit between CN231-A and CN231-B?
Y N
I
o Connect CN202.
o Turn the main switch on.
Is the voltage between CN202-B4 and TP215 within the
range 0.9 volts to 1.3 volts?
Replace the main board.
Check and correct the harness and connector.
Replace the drum thermistor.
Check and correct the harness and/or connector.
13-41
30 April, '89