LG Microwave Not Heating or Completely Dead? Inverter Board F6645BA00GP – Fix No-Heat Failures Fast

If your LG microwave runs, hums, and shows a display but produces zero heat — or is completely dead with no response — the inverter main board has almost certainly failed. In most LG over-the-range and countertop microwaves, the inverter board controls magnetron power output and is the single most common point of failure in the cooking circuit. When it fails, the microwave may appear to run a cycle normally while producing no heat whatsoever, or it may shut down entirely with no display or response. ⚡ Leading failure point in LG LMV and LMHM series microwaves. Part F6645BA00GP is the genuine OEM replacement that restores full magnetron output and cooking power immediately.

❓ Is This the Right Part?

This is the correct fix if ALL of the following are true:

• ✔ Microwave powers on — display lights up and turntable rotates
• ✔ Door closes and latches properly — door switches are functional
• ✔ Outlet and circuit breaker confirmed OK — power supply is fine
• ✔ ONLY problem is no heat output, or unit is completely dead with no display

Not sure? Send us your model number — we'll confirm before you order.

🔧 Common Symptoms

• Microwave runs full cycle but food comes out cold — zero heat produced
• Unit is completely dead — no display, no response to any button
• Loud hum during operation but magnetron never fires
• Microwave trips the breaker or blows a fuse repeatedly
• Sparking or burning smell from the inverter area (rear of unit)
• Display works and timer counts down but no cooking occurs

✔ If these symptoms match, the inverter board is the most likely failed component in the system.

✔ In most cases, replacing this inverter board restores full cooking power immediately.

📦 Part Details

• Part Number: F6645BA00GP
• Type: Inverter Main PCB / Control Board — Genuine OEM LG
• Replaces: F6645BA00AP, F6645BA00BP, F6645BA00CP, F6645BA00DP, F6645BA00EP, F6645BA00FP
• Brands: LG
• Appliance Type: Over-the-Range & Countertop Microwave (LMV, LMHM, LMVM Series)

⚙️ Installation

Skill Level: Advanced — 45 to 60 minutes. High-voltage capacitor discharge required. Disconnect power and discharge the high-voltage capacitor before touching any internal components — microwave capacitors store lethal charge even when unplugged. Remove the outer cabinet (typically 3–5 screws on the rear), locate the inverter board mounted near the magnetron, disconnect the harness connectors and high-voltage leads, swap in the new board, and reassemble in reverse. Do not skip the capacitor discharge step.

✓ Compatible Models

Confirmed compatible with LMV2031ST, LMV2031BD, LMV2031SW, LMHM2237ST, LMVM2033ST, LMV1762ST, LMV1764ST, LMV1831ST, LMV2031SB, plus additional LG LMV and LMHM series models. Contact us to verify your model number before ordering.

💡 Pro Tip