FailureMode
Internal power supply fault
- ID
fm:internal-power-supply-fault- IRI
https://solarlattice.org/kb/fm/internal-power-supply-fault- Status
- active
- Also known as
- Power Supply Board
An internal power supply fault means the low-voltage supply that runs the inverter's control electronics has failed. On the front panel, the POWER working light is off, which the manual reads as the power supply not working. The RUN, GRID and FAULT lights can also stay dark, so a dark FAULT light does not prove the inverter is healthy. To confirm, check the LED panel and see whether the control panel powers up at all. The fix is to replace the power supply for the inverter controls. An inverter specialist does this, following the manufacturer's board replacement instructions.
<!-- review notes
- sentence 1: support check: partial - The passages mention a 24 VDC power supply for inverter controls being replaced, but do not define a fault as failure of that low-voltage supply.
- sentence 4: support check: partial - The LED table supports reading the POWER light as an indicator of whether the control panel is energized, but nothing explicitly says to check it to confirm this fault.
- sentence 5: support check: partial - The table shows an inverter specialist replaces the 24 VDC supply for inverter controls as needed, and a board replacement instruction is cited, but the content of the manufacturer's instructions is not shown.
-->
Claims
affects
c1 verified · fact
Inverter
The 24 VDC supply that powers the inverter controls is a replaceable part inside the inverter.
verified by: review-workflowverified on: 2026-10-20review note: support check: partial - The service table lists replacing the 24 VDC power supply for inverter controls as an inverter repair, but nothing states an 'internal power supply fault' affects the inverter as a fault relation.
presents_as
c2 verified · fact
Inverter status LEDs off
When the POWER light is off, the power supply is not working. The RUN, GRID and FAULT lights can also go dark when the supply is down. A dark FAULT light alone is ambiguous: it can also mean there is no fault.
Light off | Power supply not working
verified by: review-workflowverified on: 2026-10-20
detected_by
c3 verified · fact
Inverter display check
Check the front-panel LEDs. If the POWER working light is off, the inverter's control supply is not energized.
verified by: review-workflowverified on: 2026-10-20
mitigated_by
c4 verified · fact
Power board replacement
Replace the 24 VDC power supply or power supply board for the inverter controls. An inverter specialist does this as needed, following the manufacturer's replacement instructions.
verified by: review-workflowverified on: 2026-10-20review note: support check: partial - The service table shows an inverter specialist replaces the 24 VDC supply as needed, and a power supply board replacement instruction is cited, but the passage doesn't state it mitigates a fault or give the manufacturer instructions' content.
Referenced by
Data