Cause

Supply Voltage Issue.

Solution

Make sure the supply voltage to the unit is within correct range.

Check the spec sheet to see if the unit is 115V/208V/230V and that the actual supplied voltage +/- 10% of the rated voltage required.

Cause

Wiring Harness Defect

Solution

Inspect the wiring harness for pinched or broken wires. Also check wiring connectors at Main PCB for any burnt connectors.

Cause

Main PCB Defect.

Solution

IF Supply Voltage  is correct and no wiring issues are found… The most common solution for this issue is to replace the Main PCB.