Ricoh FT7770 Service Manual page 566

30 April, '89
Service Call 3 - Drum Heater
o After the drum heater turns on, the drum temperature does not
reach 20°C within 50 minutes.
Is the drum heater open circuit (CN128-1, CN128-2)?
I
Disconnect CN202.
Is the drum thermistor an open circuit (CN202-B4,
CN202-A1)?
Y N
I
Does the input voltage of CN212-11 on the ac drive
board go from HIGH (+24 volts) to LOW?
o
o
Check the wiring of the drum thermistor.
Replace the drum thermistor.
Replace the drum heater or the drum thermoswitch.
I
Does the output of CN301-B15 on the dc drive
board go from
N
Does the
board go
Y N
I
\
Replace the main board.
Check and correct the harness and connector.
Replace the dc drive board.
Check and correct the harness and connector.
Correct the harness and connector of the ac line
for the drum heater.
Replace the ac drive board.
HIGH (+24 volts) to LOW?
output of CN201-A16 on the main
from LOW to HIGH (+3 volts)?
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