Fujitsu AUXB04GALH Service Manual page 150

Trouble shooting 72
Outdoor air unit - No Power
Check Point 1 : Power supply
Is not the breaker down?
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
Check Point 2 : Check Protector (20A)
Check protector open / short
If the protector is open circuit, replace it.
OK (No short circuit)
Check Point 3 : Check AC line
Check AC line open / short
NG (Short circuit)
Check Point 4 : Check short circuit Filter PCB
Disconnect the wire between Filter PCB and reactor,
check short circuit of AC line.
If there is short circuit, replace the Filter PCB.
OK (No short circuit)
Check Point 5 : Check short circuit Diode bridge
Connect the disconnected wire(s) on the check point 4,
disconnect the wire between Diode bridge and Capacitor,
check short circuit of AC line.
If there is short circuit, replace the Diode bridge.
OK (No short circuit)
Check Point 6 : Check short circuit Capacitor
Connect the disconnected wire(s) on the check point 5,
disconnect the wire between Capacitor and Filter PCB,
check short circuit of AC line.
If there is short circuit, replace the Capacitor.
OK (No short circuit)
Check Point 7 :
Check short circuit Power supply PCB
Connect the disconnected wire(s) on the check point 6,
disconnect the wire of Fan motor, check short circuit of
AC line.
If there is short circuit, replace the Power supply PCB.
OK (No short circuit)
Check Point 8 : Check Fan Motor
Check open / short of FAN motor
Refer to the Service Parts Information 14-1
If there is short circuit, replace FAN motor.
Forecast of Cause :
1. Power Supply failure 2. Outside cause 3. Electrical Component defective
Check Point 9 : Short circuit check on DC circuit
Disconnect the connector (CN200) on the Power supply PCB
and check the short circuit
1. DC12V line ( CN200 Pin 1- 5 )
2. DC 5V Line ( CN200 Pin 1 - 3 )
3. DC 15V-1 Line ( CN500 Pin 3 - 4 )
4. DC 15V-2 Line ( CN530 Pin 3 - 4 )
If one of them is short circuit, replace the Power supply PCB
Check Point 10 : Check short circuit of actuators (for DC12V)
Disconnect the CN10 (EEV1) on the Main PCB, and check short circuit
on Main PCB CN 4 Pin 1 - 5.
If the short circuit disappears, replace the EEV coil.
Disconnect the CNC01 (WRC) on the Main PCB, and check short circuit
on Main PCB CN 4 Pin 1 - 5.
If the short circuit disappears, check the WRC wire, WRC.
Disconnect the CNB01 (Ext.Out) on the Main PCB, and check short circuit
on Main PCB CN 4 Pin 1 - 5.
If the short circuit disappears, check the Ext. device or wiring.
Disconnect the CN2 (TransmissionPCB) on the Main PCB, and check
short circuit on Main PCB CN 4 Pin 1 - 5.
If the short circuit disappears, replace the Transmission PCB.
Disconnect the CN22 (Interconnecting wire) on the Main PCB, and check
short circuit on Main PCB CN 4 Pin 1 - 5.
If the short circuit disappears, replace the Filter PCB.
If the short circuit appears after disconnecing actuators, replace the Main
PCB.
Check Point 11 : Check short circuit of actuators (for DC5V)
Disconnect the CN14 (SW PCB) on the Main PCB, and check short circuit
on Main PCB CN 4 Pin 1 - 3.
If the short circuit disappears, replace the SW PCB.
Disconnect the CN18 (Receiver unit *Option) on the Main PCB, and check
short circuit on Main PCB CN 4 Pin 1 - 3.
If the short circuit disappears, check the wire, Receiver unit.
Disconnect the CN2 (Transmission PCB) on the Main PCB, and check
short circuit on Main PCB CN 4 Pin 1 - 3.
If the short circuit disappears, replace the Transmission PCB.
Disconnect the CN21 (Interconnecting wire) on the Main PCB, and check
short circuit on Main PCB CN 4 Pin 1 - 3.
If the short circuit disappears, replace the Power supply PCB.
If the short circuit appears after disconnecing actuators, replace the
Main PCB.
04-80
OK (No short circuit)
OK (No short circuit)
OK (No short circuit)