Trouble shooting Si04-11580 Service Diagnosis5.14 Faulty Outdoor Unit PCB and Transmitting/ReceivingCircuitRemoteControllerDisplay∗Outdoor unit LEDDisplayA 3333Method ofMalfunctionDetection1. The proper program operation of the microcomputer is checked by the program.2. Signals transmitted from the outdoor unit to the indoor unit are received by the outdoor unititself in indoor unit -outdoor unit signal transmission mode, and proper receiving of thesignals by the indoor unit is checked.MalfunctionDecisionConditions1. When the microcomputer program does not function properly.2. When the signals transmitted from the outdoor unit to the indoor unit are received by theoutdoor unit itself in indoor unit-outdoor unit signal transmission mode, but not properly.3. When the zero cross signal is not detected over 10 seconds.SupposedCauses" Display disabled by faulty power supply." Microcomputer program run-away due to an external factor.∗Noise∗Momentary voltage drop∗Momentary power failure, etc." Faulty outdoor unit PCB.TroubleshootingCheck No.13Refer to P.91Is the grounding proper?Is there any disturbance?Is it normal?NONONONOTurn off the power,remove No. 2 of the terminal board,and turn the power on again.Check the grounding.Turn the power off and back on again.Doesthe same LED indicationappear again?YESYESYESYESCorrect the power supply.∗ Check the voltage at the terminalsmarked with "5V" and "GND".Replace the outdoor unit PCB.Provide the grounding.The malfunction may be caused by anexternal factor, rather than defective parts.Locate the cause of the noise, etc.,and correct the situation.Locate the cause of the power supplywaveform disturbance, and takenecessary measures.Replace the outdoor unit PCB.Replace the indoor unit PCB. (R1958)Check No. 13Power supply waveform checkYESNOCheck the 5-VDC power supply ofthe outdoor unit PCB.Is the voltage 5 ± 0.5 V?Check the power supply voltage.YESNOIs it at the rated voltage?CautionBe sure to turn off power switch before connect or disconnect connector,or parts damage may be occurred.
