Fujitsu AMUG24LMAS Service Manual page 93

Troubleshooting 33
No operation (Power is ON)
Forecast of cause:
1. Setting / connection failure
2. External cause
3. Electrical component defective
4. Communication error between controller PCB
and wired remote control
Check Point 1 :
Check indoor and outdoor installation condition
Indoor unit - Check incorrect wiring between indoor unit and remote control.
Or, check if there is an open cable connection.
Are these indoor unit, outdoor unit, and remote control suitable model numbers to connect?
>> If there is some abnormal condition,correct it by referring to Installation manual and
Data & Technical Manual.
OK
Turn off power and check/ correct followings.
Is there loose or removed
communication line of indoor unit and outdoor unit?
OK
Check Point 2 :
Check external cause at indoor and outdoor (voltage drop or noise)
Instant drop -----
Check if there is a large load electric apparatus in the same circuit.
Momentary power failure -----
Check if there is a defective contact or leak current in the power supply circuit.
Noise -----
Check if there is any equipment causing harmonic wave near electric line.
(Neon bulb or electric equipment that may cause harmonic wave)
Check the complete insulation of grounding.
OK OK
Check Point 3 :
Check wired remote control and controller PCB
Check voltage at CN300 of controller PCB.
(Power supply to remote control)
>> If it is DC12V, remote control is failure.
(Controller PCB is normal)
Replace remote control
>> If it is DC 0V, controller PCB is failure.
(Check remote control once again)
Replace controller PCB
OK
Check Point 3 :
Check wired remote control (2 wire type)
If the connection condition is normal,
replace the wired remote control.
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