LG Microwave: burning, not heating

Professional Repair Guide

What is this symptom?

Is your LG microwave emitting a burning smell and failing to heat food? This indicates potential internal component failures, such as a faulty magnetron or high-voltage diode. Don't ignore these signs, as they could lead to further damage if not addressed promptly.

Urgency: High

Important Tips for LG Models

Common LG microwave heating failure causes include magnetron failure and high-voltage diode issues

Possible Causes

Failed magnetron

How to Identify: Burning smell coinciding with no heating; magnetron burn marks or obvious failure signs; consistent with community and repair sources

Part: Magnetron

Faulty high-voltage diode

How to Identify: Microwave runs but no heat; diode often fails with no visible external signs; community guides list as cause

Part: High-voltage diode

Malfunctioning control board or power supply

How to Identify: Burning odor without heating; visual burn marks on control board; other components not showing failure

Part: Control board / power supply board

Burned thermal fuse or thermostat

How to Identify: No heating paired with overheating shutdowns; visible discoloration on fuse/thermostat

Part: Thermal fuse / thermostat

DIY Solutions

Inspect and clean interior for simple causes

Easy 10-30 minutes

Tools Needed: soft cloth, mild cleaner

Unplug the microwave.
Open the door and inspect for burned food debris and clean interior surfaces.
Run a steam cleaning with water and baking soda to reduce odor if no component failure identified.

⚠️ Safety First: Ensure unplugged before cleaning.

Check door switches and simple electrical resets

Moderate 15-45 minutes

Tools Needed: screwdriver, multimeter

Unplug the microwave.
Remove casing per service manual (if confident with safety).
Test door switches for continuity with multimeter.
Reassemble and test after resetting power.

⚠️ Safety First: High-voltage risk; discharge capacitor before touching internals.

Next step

Choose the next step for burning, not heating

Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.

Check during diagnosis

Most relevant component to inspect

Microwave Magnetron

Generates microwave energy for heating food and requires high-voltage service procedures.

Typical part-only price: $80 - $220
DIY difficulty: Hard
Estimated time: 60-120 mins

Optional: enter your model number

Where can I find the model number?

Check the rating label around the door, lid, frame, rear panel, or inside the appliance cabinet. Use the complete model number, including suffixes.

Find a part that fits my model

Verify the complete model and part number on the retailer's compatibility page before ordering.

Other parts options

Check related components first; use model search as a fallback.

Possible related component

Power Control Board

Distributes and switches electrical power for the appliance's major loads.

$90 - $260 · Hard · 30-75 mins

Check fit & price

Possible related component

Main Control Board

The central brain of the appliance that controls all components, cycles, and timings.

$120 - $280 · Medium · 20-40 mins

Check fit & price

Possible related component

Thermal Fuse

A safety device that cuts off power to the appliance if it starts to overheat.

$10 - $20 · Easy · 10-20 mins

Check fit & price

Model number required

Model-compatible Microwave parts

Enter the complete model number to browse compatible replacement parts. This is a model-based parts search, not a diagnosis that a specific component failed.

Find a part that fits my model

Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. We may earn a commission from other qualifying purchases or service requests made through links on this page, at no additional cost to you. Recommendations are based on repair relevance, not commission rate.

Professional Repairs

Replace magnetron

Estimated Cost: $80 - $200 (part) plus labor

Replace high-voltage diode or capacitor

Estimated Cost: $40 - $120 (parts) plus labor

Control board/power supply repair

Estimated Cost: $100 - $250

When to Call a Professional

Burning smell persists after interior cleaning

Smoke, sparks, or visible component damage

Microwave runs but still fails to heat after basic checks

Internal component diagnostic required

Preventive Maintenance

Clean interior regularly: Food residue buildup that can cause odors
Frequency: weekly to monthly
Avoid metal or improper containers: Sparks and damage to internal components
Frequency: each use

Frequently Asked Questions

Why is my LG microwave burning, not heating?

Common causes include a failed magnetron, faulty high-voltage diode, or malfunctioning control board.

How do I fix LG microwave burning, not heating myself?

Start by cleaning the interior and checking door switches for continuity. Unplug the microwave before inspecting.

How much does it cost to fix burning, not heating?

Repair costs range from $40 to $250 depending on the components needing replacement.

When should I call a technician for burning, not heating?

If simple DIY solutions don't resolve the issue, or if you notice extensive internal damage, contact a professional.

References & Sources

LG Microwave Not Heating common causes Repair-Blog

Community Analytical Insights

Guidance from available sources; statistical claims are shown only for samples of at least 10 discussions

Common Issues Reported by Users

Burnt or damaged waveguide cover
Faulty magnetron
Defective high voltage capacitor

User Suggested Solutions

Inspect and replace the waveguide cover. First, unplug the microwave. Remove the cover by taking out the screws. Inspect for burns or damage. If damaged, replace it with a new one. Reassemble and test the microwave.
Test and replace the magnetron. Unplug the microwave and discharge the capacitor. Remove the outer casing and locate the magnetron. Use a multimeter to test for continuity. If faulty, replace it with a new magnetron.
Check and replace the high voltage capacitor. Unplug the microwave and discharge the capacitor. Remove the casing and locate the capacitor. Test it with a multimeter. If defective, replace it with a new one.

Limited-source guidance; percentages and success-rate claims are not shown
View Sources

Data compiled from real discussions on r/appliancerepair and r/Appliances:

Lg microwave burn on side

Community Discussions

burn on side, loud noise, smoke, crackling noise

Replace the waveguide cover or the microwave entirely if the internal parts are burnt.

LG Microwave: burning, not heating

What is this symptom?

Important Tips for LG Models

Possible Causes

Failed magnetron

Faulty high-voltage diode

Malfunctioning control board or power supply

Burned thermal fuse or thermostat

DIY Solutions

Inspect and clean interior for simple causes

Check door switches and simple electrical resets

Choose the next step for burning, not heating

Microwave Magnetron

Other parts options

Power Control Board

Main Control Board

Thermal Fuse

Model-compatible Microwave parts

Professional Repairs

Replace magnetron

Replace high-voltage diode or capacitor

Control board/power supply repair

When to Call a Professional

Preventive Maintenance

Frequently Asked Questions

References & Sources

Community Analytical Insights

Common Issues Reported by Users

User Suggested Solutions

Inspect and replace the waveguide cover. First, unplug the microwave. Remove the cover by taking out the screws. Inspect for burns or damage. If damaged, replace it with a new one. Reassemble and test the microwave.

Test and replace the magnetron. Unplug the microwave and discharge the capacitor. Remove the outer casing and locate the magnetron. Use a multimeter to test for continuity. If faulty, replace it with a new magnetron.

Check and replace the high voltage capacitor. Unplug the microwave and discharge the capacitor. Remove the casing and locate the capacitor. Test it with a multimeter. If defective, replace it with a new one.

Community Discussions

User Comments (0)