Service Manual

Trouble shooting 73
Indoor Unit - No Power
(Wall mounted type)
Forecast of Cause :
1. Power Supply failure 2. Outside cause 3. Electrical Component defective
Is not the breaker down?
Check Point 1 : Power supply
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
Is not open circuit ?
If the fuse was open state, check the cause of short circuit
on the AC circuit before replacing the spare parts.
Check Point 2 : Fuse or Thermal fuse of Indoor unit
NG (Short circuit on AC circuit)
Disconnect AC power input wires and check short circuit
Check Point 3 : Short circuit check on AC circuit
NG (Short circuit on AC circuit)
Check Resistor R101, Open / Short circuit check
Check Point 5 : Resistor R101
Check short circuit between Pin No.1 and Pin No. 6 of CNB01
(DC 13.5V circuit )
1. Disconnect EEV connector
2. Disconnect SP motor
3. Disconnect Wired Remote Controller
4. Disconnect Transmission PCB
Check Point 6 : Short circuit check on DC13.5V circuit
Check short circuit between Pin No.5 and Pin No. 7 of CN3 (TEST)
(DC 5.0V circuit )
1. Disconnect Indicator PCB
2. Disconnect SW PCB
3. Disconnect Transmission PCB
Check Point 7 : Short circuit check on DC5.0V circuit
NG (Open circuit on R101)
OK
OK (Not Open)
ReplaceMain PCB
OK (Open circuit)
NG (Short circuit )
NG (Short circuit )
Disconnect FAN motor and Check short circuit
Check Point 4 : Power supply circut of FAN Motor
NG (Short circuit)
2.2 Ohm + 5%
-
Pin No.1 and Pin No.7 of CN18
or
04-82