Daikin Indoor Unit Multi-Split Type Air Conditioner FTXR12TVJUS

Warning: Ensure the voltage between (+) and (–) of the diode bridge (DB1) is about 0 V before proceeding

Enter the voltage between (+) and (–) of the diode bridge (DB1)

Measure the resistance between the pins of the DB1 referring to the table below.

Enter the resistance between the pins of the DB1

Is the resistance ∞ or less than 1 kΩ?

If the resistance is ∞ or less than 1 kΩ, short circuit occurs on the main circuit.

Sign off on the main circuit short check

Warning: This check requires trained personnel with PPE!

Enter the power supply waveform measurement between No. 1 and No. 2 on the terminal board

Is the power supply waveform a sine wave as shown in Fig.1?

Is there any waveform disturbance near the zero-cross as shown in the sections circled in Fig.2?

Upload a photo of the measured waveform

Sign off on the power supply waveform check

Warning: Check the main circuit for short circuit before proceeding

Warning: Never touch any live parts

Warning: Ensure firm contact between the multimeter probes and the test points

Sign off on the capacitor voltage check

Warning: Disconnect the connectors of the thermistors from the PCB before proceeding

Thermistors disconnected from the PCB

Resistance of room temperature thermistor

Note: If the room temperature thermistor is soldered on a PCB, remove the PCB from the control PCB to measure the resistance.

Resistance of indoor heat exchanger thermistor

Note: If the connector of indoor heat exchanger thermistor is soldered on a PCB, remove the thermistor and measure the resistance.

Sign off on the thermistor resistance check

Warning: This procedure requires trained personnel with PPE!

Install an inverter analyzer instead of a compressor.

Charged voltage of the built-in smoothing electrolytic capacitor dropped to 10 VDC or below?

Terminals (U,V,W) not touching each other?

Power transistor test operation activated?

Diagnose according to 6 LEDs lighting status.

If all the LEDs are lit uniformly, the compressor is defective.