The power supply board (often called the PSU or power board) is the component responsible for converting the high-voltage AC (alternating current) electricity from your wall outlet into various low-voltage DC (direct current) outputs used by the internal circuits of the TV. It is a critical component that powers nearly every other system in the television, from the main board to the backlight.
REMEMBER TO ALWAYS USE CAUTION WHEN HANDLING POWER SUPPLY BOARDS! Prioritize safety as you proceed.
Check out our helpful YouTube video covering How To Get Started below:
🔋 Key Functions of the Power Supply Board
1. AC to DC Conversion
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Converts 110V–240V AC from your home outlet into multiple DC voltages (commonly 12V, 24V, 5V, and 3.3V).
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These voltages power components like the:
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Main board
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T-Con board
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Speakers/audio amplifier
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Panel drivers
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2. Voltage Regulation and Distribution
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Regulates voltage levels to ensure stability and safety.
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Prevents overvoltage and under-voltage issues that could damage sensitive components.
3. Startup and Standby Power Management
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Delivers standby voltage (typically 3.3V or 5V) to keep the TV ready to power on.
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Responds to power-on signals from the main board and ramps up full power to the system.
💡 Power Supply vs. LED Driver: What's the Difference?
| Feature | Power Supply Board | LED Driver |
|---|---|---|
| Primary Role | Converts AC to DC and distributes it | Powers and regulates LED backlights |
| Controls | All voltages used by TV circuits | Only LED backlight voltage and current |
| Presence in TVs | Found in all TVs | Sometimes separate, often integrated |
| Common Voltages | 3.3V, 5V, 12V, 24V | High-voltage DC (often 50–150V+) |
🛠️ Integrated Designs
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In many modern TVs, especially LED/LCD models, the LED driver circuit is built into the power supply board.
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This integrated design reduces component count and manufacturing complexity.
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In this case, the power board:
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Handles both general power distribution and backlight control.
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May include a connector labeled LED+/- that leads to the backlight array.
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🔧 Separate LED Driver Boards
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Some TVs, especially larger or premium models, have a dedicated LED driver board.
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These boards:
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Receive a standard DC voltage (e.g., 24V) from the power supply.
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Boost and regulate voltage to power the LED backlights safely and efficiently.
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🛑 Common Symptoms of a Failing Power Supply Board
| Symptom | Possible Cause on Power Board |
|---|---|
| TV won’t power on | Failed AC-DC conversion or blown fuse |
| No standby light | No 5V/3.3V standby voltage output |
| Clicks on but no picture or sound | Main voltage rail failure |
| No backlight (but with sound) | Failed LED driver section (if integrated) |
| TV powers off randomly | Faulty capacitors or overheating |
🧰 Diagnosis and Replacement
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Visual clues:
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Check for bulging or leaking capacitors, burn marks, or a blown fuse.
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Testing:
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Use a multimeter to verify key voltage outputs (only if you're comfortable working around high-voltage components).
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Replacement:
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Power boards are typically modular and easy to replace with basic tools.
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Match by part number, not just TV model, to ensure compatibility - especially if it includes the LED driver.
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💡 TVpartsToday Tip:
If your TV has no power, flickers, or has a black screen with sound, the power supply board or LED driver may be at fault. In TVs where these are combined, a single board swap can resolve both power and backlight issues. Always check for visibly damaged components and test voltages before replacing.
💬 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!
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.
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