Daikin Outdoor Unit Air Conditioner RXL12WMVJU9

EV connector correctly connected to the PCB

EV generates a latching sound when power is turned off and on again

Continuity present when connector is disconnected and checked with a multimeter

Check the continuity between the pins

Outdoor unit PCB (main PCB) is not faulty

Sign off on the electronic expansion valve check

Warning: Ensure the voltage between (+) and (–) of the power module is about 0 V before proceeding

Enter the voltage reading between (+) and (–) of the power module

Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the connector, press the protrusion on the connector.

Was the compressor harness connector successfully disconnected?

Measure resistance between the terminals of the power module and the terminals of the compressor with a multimeter.

Enter the resistance reading between the terminals of the power module and the terminals of the compressor

Evaluate the measurement results

Sign off on the power module check

Warning: This procedure requires trained personnel with PPE!

Disconnect the connector of thermistor ASSY from the PCB to measure the resistance between the pins using multimeter.

Enter the measured resistance value

Does the measured resistance value match the listed value?

To check the thermistor soldered on a PCB, disconnect the PCB from other PCB/parts, and measure the resistance between the both ends of soldered thermistor.

Enter the measured resistance value for the soldered thermistor

Does the measured resistance value for the soldered thermistor match the listed value?

Note: When replacing the defective thermistor(s), replace the thermistor as ASSY.

Sign off on the thermistor resistance check

Ensure that the voltage is within 320 VDC

Set operation off and power off. Disconnect the connector S70 or S71

Check that the voltage between the pins 4 - 7 is 320 VDC

Check that the control voltage between the pins 4 - 3 is 15 VDC

Check that the rotation command voltage between the pins 4 - 2 is 0 ~ 6.5 VDC

Keep operation off and power off. Connect the connector S70 or S71

Check whether 4 rotation pulses (0 ~ 15 VDC) are input at the pins 4 - 1 when the fan motor is rotated 1 turn by hand

When the fuse is melted, check the outdoor fan motor for proper function

Warning: This procedure should be performed by a trained technician

Measure the power supply waveform between No. 1 and No. 2 on the terminal strip

Check if the power supply waveform is a sine wave (Fig.1)

Check if there is waveform disturbance near the zero-cross (sections circled in Fig.2)

Upload a photo of the measured waveform