Samsung 65" QLED TV - Power Supply Capacitor Failure (October 2025)
Bulging capacitors on Samsung QLED power supply - note the domed tops indicating failure
Carefully removing old capacitors with desoldering wick and flux
New 105°C rated capacitors installed for improved reliability
Customer brought in a Samsung QN65Q80C that wouldn't turn on. No standby light, no clicking, nothing. Completely dead.
This is usually either a blown fuse or failed capacitors in the power supply. On Samsung QLED TVs from this generation, it's almost always capacitors.
Opening It Up
Removed the back panel. The power supply board had several visibly bulging capacitors. The tops were domed instead of flat. Classic failure mode for QLED TVs.
Diagnosing the Problem
Started with basic voltage checks. All the main rails were dead. No 5V standby, no 12V, nothing. The power supply wasn't even trying to start.
Checked the fuse. Good. Checked the bridge rectifier. Good. So the problem was downstream in the switching circuit.
The Repair
Replaced all the electrolytic capacitors on the power supply board: - 4x 1000µF 10V (replaced with 1000µF 16V 105°C) - 2x 470µF 25V (replaced with 470µF 35V 105°C) - 1x 220µF 25V (replaced with 220µF 35V 105°C)
Total cost in parts: about $3. The higher voltage and temperature ratings ensure longer life. This is critical for QLED TVs which run hotter than standard LED models.
Testing and Verification
Plugged it in. Standby light came on immediately. Pressed power button. TV turned on perfectly. Let it run for 2 hours to make sure it was stable. QLED brightness and color accuracy were perfect.
Checked all the voltage rails with a multimeter. All stable and within spec.
Why This Happens
Samsung used cheap 85°C rated capacitors in a hot power supply. They degrade over time. This is a known issue with Samsung QLED TVs from 2020-2024.
The fix is simple if you can solder. Takes about 30 minutes. But most people just buy a new TV.
Related Repairs
This same issue affects LG QLED models and TCL QLED TVs. The root cause is identical: cheap capacitors in high-temperature environments.
Prevention Tips
Use a surge protector to prevent voltage spikes. Consider preventive maintenance every 5-7 years to replace aging capacitors before they fail.