Fujitsu AOG30KATA Series Service Instruction page 69

Trouble shooting 26
OUTDOOR UNIT Error Method:
Heat Sink Thermistor Error
Detective Actuators:
Heat sink temperature thermistor
Forecast of Cause :
1. Connector connection failure, open
2. Thermistor failure
3. Inverter PCB failure
Check Point 1 : Check the connector connection and cable open
Connector connection state check
Cable open check
OK
Check Point 2 : Check the thermistor
Thermistor characteristics check
(Disconnect the thermistor from the PCB and check.)
* For the thermistor characteristics, refer to the "Service Parts Information 8".
OK
Check Point 3 : Check voltage of Inverter PCB (DC5.0V)
Main PCB P700:1-3 voltage value =5V
Remove the thermistor from Inverter PCB, check the voltage.
1 2 3
1 2 3
P700
If the voltage does not appear, replace Inverter PCB,
and execute the check operation again.
Indicate or Display:
Error code : 77
Detective details:
Heat sink temperature thermistor short or open detected
02-27
Outdoor unit :
Mode Error L1 L2
2 7 7
: Light OFF : Light ON
DC
L3 L4 L5 L6
n : n times blinking