LG · Microwave Serious
F-7 — Inverter / power module fault (NeoChef inverter models)
On LG NeoChef and other inverter microwaves, F-7 indicates the inverter power module has reported a fault — overcurrent, overheat, or self-test failure. The microwave will not heat.
- Keep using it?
- Limited use only
- DIY difficulty
- Hard
- Verified against
- lg.com ↗
How to fix it
- Unplug for 5 minutes and retest with a cup of water — confirm no heat output before disassembly.
- Vacuum the rear vent grilles and check that the cooling fan spins freely.
- ONLY trained technicians should open the chassis — inverter capacitors hold dangerous charge.
- Inspect the inverter board for burn marks, bulged caps, or burnt connectors.
- Reseat the inverter-to-magnetron and inverter-to-main-board harnesses.
- Test the magnetron filament; if shorted, replace it before replacing the inverter.
- Replace the inverter (Smart Inverter) module if visibly damaged or if the magnetron tests good.
- Run a 1-minute water test; if F-7 returns, escalate.
Why it happens
Typical signs: F-7 on display on a NeoChef / inverter model · No heat even though fan and turntable run · Audible click then shutdown shortly after start · Inverter fan may run faster than normal
- Inverter board failure The Smart Inverter module has failed — the most common cause on this code.
- Failed magnetron A shorted magnetron pulls excessive current and trips the inverter's self-protect.
- Blocked cooling airflow Lint or grease on the inverter heatsink causing thermal shutdown.
- Loose inverter harness Connector to the magnetron or main board has loosened.
Parts you may need
If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.
More LG microwave codes
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: lg.com.