How do I fix LG Microwave Inverter Board Replacement - Signs & How-To?

Follow the step-by-step diagnosis below. The most likely fix is identified by checking power, sensor resistance, and control-board signals in order — using a multimeter and the part numbers documented in the parts reference table.

Can I keep running the equipment with this fault active?

Generally no. Faults on Appliance units are emitted when a sensor, safety, or control circuit is outside its operating envelope. Running through an active fault risks compressor, heater, or control-board damage. Diagnose and clear the fault first.

What part is most commonly replaced for LG Microwave Inverter Board Replacement - Signs & How-To?

The most frequently replaced parts for LG Microwave Inverter Board Replacement - Signs & How-To are listed in the Parts Reference section of this guide with OEM part numbers and typical price ranges. Check the table for direct replacements.

Is LG Microwave Inverter Board Replacement - Signs & How-To a DIY repair or do I need a technician?

Sensor swaps, fan motor replacements, and condenser cleaning are typical DIY-level repairs. Anything involving refrigerant, gas, or high-voltage (>240V) work requires a licensed technician for both safety and code-compliance reasons.

LG Microwave Inverter Board Replacement - Signs & How-To

Q: What does LG Microwave Inverter Board Replacement - Signs & How-To mean?

F11, F-13, F-14, F-15, F-16, F-17, or F-19 fault codes plus erratic heating or power cycling mean inverter board failure. Replacing it restores power control.

LG Microwave Inverter Board Replacement — What This Part Does

The inverter board in LG inverter-model microwaves is the high-voltage power supply that drives the magnetron. Instead of cycling on and off like older transformer-based models, the inverter board runs continuously and modulates power output for precise cooking control. It fails from loose or overheated wiring, internal component breakdown, magnetron load problems, or cooling system issues that trigger thermal protection.

LG’s service documentation states that the inverter board should not be repaired or adjusted in the field. When the control board detects overcurrent, overvoltage, Vdc protection faults, inverter communication errors, or heat-sink temperature problems, it logs a fault code and shuts down microwave operation to prevent damage.

Jump to Replacement Steps

Signs It Needs Replacing

F11 or F-11 error code on the display This is an inverter communication error, meaning the main control board cannot talk to the inverter module.
F-13, F-14, F-15, or F-19 fault codes These codes indicate inverter overcurrent, overvoltage, or Vdc protection trips, pointing to power circuit or wiring problems inside the inverter assembly.
F-16 error code Inverter heat-sink error, often caused by a failed cooling fan or the inverter module itself overheating.
F-17 error code Inverter temperature sensor fault, which can be the sensor itself or the inverter board circuit that reads it.
Microwave runs but does not heat food at all The inverter board may be failing to deliver high voltage to the magnetron even though the control panel responds normally.
Erratic or intermittent heating, or the unit cycling on and off Inverter power output becomes unstable when internal components on the board degrade or wiring connections loosen.

How to Replace It

Unplug the microwave from the wall outlet and wait at least 60 seconds for the high-voltage capacitor to discharge before opening the cabinet.
Remove the screws securing the outer cover (typically along the top and sides) and lift the cover away to expose the internal components.
Locate the inverter board assembly, usually mounted to the lower or side chassis with its heat sink visible, and take a photo of all wire connections before disconnecting anything.
Inspect all wiring harness connectors and terminals at the inverter board for looseness, discoloration, melted insulation, or poor crimps, and check magnetron wiring and fan connections as well since these can cause inverter faults.
Disconnect the wire harnesses from the inverter board by gently pulling on the connector bodies, not the wires, then remove the mounting screws or clips securing the inverter assembly to the chassis.
Lift out the old inverter board and heat-sink assembly and compare it physically to the new replacement part to confirm match.
Install the new inverter board in the same orientation, secure it with the original mounting hardware, and reconnect all wire harnesses exactly as photographed, pressing each connector fully home.
Replace the outer cover and all screws, plug the microwave back in, and run a heating test with a microwave-safe container holding 1 liter of water to confirm normal operation and that all fault codes have cleared.
If you have access to a microwave survey meter, verify that leakage is below 1 mW/cm² with a 275 ml water load, as specified in LG service documentation for post-repair energy checks.

The Part You Need

Part	Notes
LG inverter board assembly (inverter module)	Amazon \| Look for your exact model and serial number on the label inside the door frame or on the back panel, then cross-reference that model number with LG parts suppliers to find the correct inverter board part number for your specific inverter-model microwave.

If this part is failing you may also see one of these codes:

When to Call a Pro

Call a professional appliance technician if you are uncomfortable working around high-voltage components or do not have the tools to safely discharge the capacitor and verify proper grounding. LG service documentation requires resistance checks on the magnetron and wiring-to-inverter circuits to rule out magnetron or cable faults before replacing the inverter board. If fault codes persist after inverter replacement, the magnetron, cooling fan, temperature sensor, or main control board may also be failed, and diagnosis with a multimeter and the factory service manual is necessary to avoid replacing the wrong part.