One Enphase microinverter isn't producing. How do I prove whether it's the micro or the module?

The short answer

Check breakers, voltage and connectors, reconnect DC and watch the LED, then swap DC with the next module.

Plain explanation

From the Enphase manual for the IQ8 microinverter: Qualified: AC breakers closed. Utility V in range. The rest of the checklist is below; work through it in order. Installer only: DC and AC work on a live PV system is dangerous, so owners should note the code and call their installer.

Steps from the source

Qualified: AC breakers closed
Utility V in range
Check connectors/rodent damage
DC disconnect/reconnect: solid green 6 s then blinks
Swap DC with adjacent module
Enphase Support

Source

Enphase IQ8 Series Installation & Operation Manual IOM-00068-3.0, §5, §5.2 p27-28enphase.com ↗

Where installers ask this

General guidance based on the manufacturer's manual or the named source. Always follow the current manual for your exact model and your national code. DC and AC electrical work is for qualified installers only. Not affiliated with or endorsed by any brand named; trademarks belong to their owners.