Fujitsu AUXB04GALH Service Manual page 124

Trouble shooting 46
OUTDOOR UNIT Error Method:
Heat Sink Temp Sensor Error
Detective Actuators:
Inverter PCB
Forecast of Cause :
1. Heat sink Thermistor open / short circuit
Check Point 1 : Check connection of Connector
Check if connector is loose or removed
Check erroneous connection
Check if thermistor cable is open
>> Reset Power when reinstalling due to removed connector or incorrect wiring.
OK
Check Point 2 : Check voltage of Inverter PCB (DC5.0V)
Inverter PCB (CN360:1-2) voltage value = 5V
Remove the thermistor from the inverter PCB and check the voltage
If the voltage does not appear, replace Inverter PCB .
Indicate or Display:
E. 77.1
Outdoor Unit : E. 77. 1
Error Code
Detective details:
Heat sink temperature thermistor open/short circuit detected
Filter LED Continuous Flash.
: 77
04-54