Cause: Internal fault comes when there is an hardware issue in drive power card or control card. This means there is a communication error between the control card and the power card.

danfoss a38 alarm indicates Internal fault. This means a fault in the VFD's internal communication system, where the control card and the power card are unable to communicate properly

Troubleshooting Steps:

Follow these steps to correct danfoss a38 alarm:

• Drive drive using multimeter.
• Check physically - any visual signs of burnt boards?
• Check drive hardware.
• Try to replace drive control card or power card.