F42 Serious Hard — consider a tech
LG Oven F42 — Induction overvoltage / DC-link voltage error
LG Oven · Error code F42
What F42 Means
The inverter board on an LG induction range has detected DC-link voltage outside the safe operating window. Cooktop output is shut down.
Symptoms
- F42 or F-42 on display
- Cooktop zones go dead
- Code may follow a brief power-line event (surge, brownout, generator switchover)
- Smell of hot electronics in some failures
Common Causes
1
Incoming line voltage out of spec
Utility surge, undersized generator, or shared neutral problem.
2
Failed inverter board input capacitors
Bulk caps degraded; DC bus collapses or rings.
3
Failed inverter board IGBTs/control circuit
Switching circuit cannot regulate the bus.
4
Loose/oxidized service connection
Bad neutral or loose lug at the range terminal block.
How to Fix It
- Power off at the breaker for 60 seconds.
- Measure line voltage at the range terminal block — both legs to neutral should be ~120 V; leg-to-leg ~240 V. Out-of-spec voltage = utility/wiring issue first.
- Inspect the range terminal block and service cord for discoloration or loose lugs; retorque.
- If line voltage is correct and F42 persists, the inverter board is the likely failure — replace it.
- Do not keep cycling power into a hard F42; repeated surges can cascade-fail the main board.
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 Oven Codes
Verified against manufacturer documentation: lgparts.com
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.