Ricoh FT7770 Service Manual page 568

30 April, '89
Service Call 5 -
o The fusing thermistor circuit opens.
o Turn the main switch off.
o Disconnect the fusing thermistor connector.
Is the fusing thermistor an open circuit (CN353-1, CN353-2)?
Disconnect CN202
Is there an open
Replace the
Check and correct the harness and connector.
Replace the fusing thermistor.
Service Call 6 -
o The hot roller temperature is less than 171°C or 175°C for
more than 30 minutes.
Note: The lower temperature limit is adjusted using SP 4-2.
Turn the main switch off.
Are the fusing lamps open circuit?
Y N
I
o Disconnect the connector (CN379) for SSRs.
o Turn the main switch on.
Is the trigger voltage between CN303-5 and CN301-B14 +24
volts?
Is the trigger voltage between CN303-5 and CN301-A15 +24
volts?
Fusing Thermistor
on the main board.
circuit between CN202-A1 and CN202-A4?
main board.
Fusing Lamp
13-44