Is your LG TV powering on but showing a blank screen? Are HDMI ports not responding, apps freezing, or the TV stuck on the logo screen? These are all red flags pointing to a faulty main board - and if you’re using a compatible LG model, the EBT66453702 (pictured below) main board might be your fix! 🧰
Main board failure is one of the most common problems we help customers solve - and the good news? It’s one of the easiest fixes you can do yourself at home. In this article, we’ll walk you through the common symptoms, how to identify this part properly (📢 always use the part number, not the board number!), and how to replace it step-by-step.
Struggling with the identification process? Check out the video below:
⚠️ Common Symptoms of a Failed LG Main Board
Here’s what might indicate that your main board (EBT66453702 in our example) is failing:
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TV powers on, but the screen stays black
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HDMI inputs don’t register any devices
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Smart apps won’t load or crash immediately
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Remote control is unresponsive
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TV freezes on the startup screen or endlessly reboots
💡 TVpartsToday Tip: If you’re hearing sound but see no image - and your backlight works - your screen is probably fine. It's likely a signal processing failure in the main board.
🔌 Try This First: Power Cycle Reset
Before jumping into hardware replacement, try this basic power reset. It can sometimes clear up temporary glitches:
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Unplug the TV from the power outlet.
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Press and hold the power button on the TV itself (not the remote) for 30 seconds.
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Wait a full 60 seconds with the TV unplugged.
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Plug it back in and power it up.
If the issues persist after this reset, your EBT66453702 main board may be at fault.
🧪 Main Board or Something Else? Here's How to Tell
Troubleshooting the right board can feel tricky - but here’s how to break it down:
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Backlight works, sound is present, but no video? Likely the T-Con or main board.
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TV turns on but no signal or input is detected? That’s your main board.
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TV won’t power on at all? That points to the power supply board.
💡 TVpartsToday Tip: Use a flashlight in a dark room to shine across the screen. If you see faint images, your backlight is working - and that means your main board is likely the issue.
Need some help with the Flashlight test? Check out our blog HERE!
🔍 Why the Right Part Number Matters (Spoiler: It’s Not EAX!)
When it comes to LG TVs, you’ll often see a lot of numbers printed on the board — but not all of them matter when ordering parts.
✅ Correct Part Number: EBT66453702 – this number is typically printed on a white barcode sticker.
🚫 Don’t Use: Numbers like EAX67872801 — this is a board number, not a part number. Board numbers are often reused across different models and revisions, so they don’t guarantee compatibility.
💡 TVpartsToday Tip: If all you have is the board number, snap a photo and send it to us — we’ll confirm the correct part number for you in no time.
🛠️ Replacing the EBT66453702: Your Step-by-Step DIY Guide
Got your replacement board ready? Here’s how to install it like a pro:
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Power off the TV and unplug it.
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Lay the TV face-down on a soft, static-safe surface (a towel works great).
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Remove the screws from the back panel using a Phillips screwdriver.
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Locate the main board — it’s the one with all the HDMI ports.
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Take clear photos of all the cable connections for easy reference.
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Carefully unplug all cables and remove any screws securing the board.
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Install your new EBT66453702, reconnect all cables, and screw the board back in place.
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Close up the back panel, plug in the TV, and power it on. 🎉
💡 TVpartsToday Tip: Don’t skip the photo step! Reconnecting everything correctly is essential, and pictures make it foolproof.
🧠 Final Thoughts: Simple Fix, Big Results
The EBT66453702 LG Main Board is a key part of many LG Smart TVs, and it’s often the cause of no-signal issues, software crashes, or input failure. Replacing it is totally DIY-friendly and way cheaper than buying a new TV or paying for a repair shop.
🚨 Just remember: Always order using the exact manufacturer’s part number, never by board number or a guess based on the model alone. The wrong board won’t work — even if it looks similar!
💬 Need Help?
If you’re still unsure about the issue or need to replace a part, reach out to TVpartsToday. We can help you identify the exact cause of the problem and provide the right replacement part!
Need a EBT66453702 specifically? Check to see if we have any in stock HERE!
Would you rather watch a video? Check out our helpful Troubleshooting 101 playlist over on YouTube!
Would you rather chat with a seasoned repair expert? Head on over to our TVRepairHelp subReddit!
📦 Need help finding the right board or part?
📞 Call us at 930-212-1975 or browse our inventory online.
🛠️ DIY-friendly parts, fast shipping, and expert support – only at TVpartsToday.