LG LMV1831ST Repair Guide
An 1.8 cu ft over the range microwave with LG’s EasyClean interior and sensor cooking. A mid size unit that fits where the 2.0 cu ft models are too tall, and it shares most of its service characteristics with the rest of the LG OTR line.
LG LMV1831ST is an over the range microwave, 1.8 cu ft microwave sold 2017 to present. Its most common repair is cooks weakly or not at all, usually $170 to $410.
- 5 common problems with causes, fixes and costs below.
- 3 error codes decoded.
- A microwave like this lasts about 7 to 10 years.
- Check the model and serial tag before you order any part.
Common problems & typical repair costs
| Problem | Likely cause | Typical fix | OEM part # | Typical cost |
|---|---|---|---|---|
| Cooks weakly or not at all | Magnetron degradation or diode failure | Professional high voltage diagnosis | not listed | $170 to $410 |
| Unit dead | Interlock switch failure and blown fuse | Replace switch set and fuse | not listed | $115 to $265 |
| Sparking during cooking | Waveguide cover burned or metal in the cavity | Replace waveguide cover. Remove metal | not listed | $5 to $60 |
| Vent fan noisy or weak | Filters loaded or blower bearings dry | Clean filters. Replace blower if still noisy | not listed | $0 to $320 |
| Turntable not turning | Coupler stripped or motor failed | Replace coupler. Motor needs cabinet access | not listed | $10 to $200 |
Costs are national averages for professional repair (parts + labor). See the linked cost guides below for full breakdowns.
Error codes
| Code | What it means |
|---|---|
| F3 | Key stuck on the touch panel |
| F5 | Humidity sensor fault |
| F7 | Control communication error |
Tech notes
The EasyClean cavity coating should never meet an abrasive pad or oven cleaner. Once it is scoured through to bare metal the cavity arcs on the exposed steel, and a cavity arcing on bare metal is the end of the appliance rather than a repair.
Sources
Where the safety, regulatory and warranty claims on this page come from. Repair costs are our own figures based on Arizona market rates and OEM parts pricing.
- Microwave Ovens, Radiation Emitting Products U.S. Food & Drug Administration The federal requirement for two independent door interlocks plus a monitoring system, and the 21 CFR 1030.10 leakage limit, why an interlock must never be bypassed.
Cost guides for this machine’s common repairs
DIY step by step instructions for this model
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