You haven't touched a power button and here it is turned on again. There are several common problems that strike these TV's. Most are simple settings to change. So no fear, you probably won't be spreading parts of your TV everywhere to fix this unless you are really determined.
Access the event logs
If manufactured in 2019 or later, your Samsung smart TV has event logs that are readily accessible, and these can help you to know what is causing the power-on events. You should be able to look at the log and determine how your TV was powered on.
In the menu on screen, select Support > About TV then select Event Logs. This will allow you to determine the reason for each power-on event. This can let you pinpoint the setting or device that is causing the issue and fix the problem.
Earlier Samsung TVs do not have this feature readily accessible.
Check your remote control.
- A stuck power button (food can do it) can lead to TV mayhem.
- Clean it and check all the buttons to see if any are stuck, especially the power button,
- While you are at it, change the batteries.
Monitor the TV and see if the problem has disappeared. If so, you are done! If not, no fear, we've only just begun, go to the next item.
The power cable is generally plugged in (not hard-wired) to the rear of your TV. It may even be under a cover. It sits undisturbed, potentially for years. Sometimes the connections become loose or poor from vibration and maybe mild oxidation.
- This can cause the TV to have its power interrupted momentarily, and it may turn on when the power is "restored".
- A good procedure is to disconnect the cable (remove the cover if needed). Inspect both the cable and port and clean any signs of dust, dirt, or oxidation with 91%+ isopropyl alcohol. Leave it disconnected for 10 minutes, and then reconnect it fully. Be sure the cable is firmly seated.
- This process just power cycled your TV, so that may have solved the problem as well.
Monitor the unit and see if the problem returns. If it's gone, you're done! If the problem is still there, go to the next step.
A software/firmware update can clear corrupted data and cause your TV to operate as it should. Performing that update may cause the problems to disappear.
The process varies by model, but you should be able to find an option to update software in the settings menu.
Monitor the TV to see if the problem recurs. if no recurrence, you are done! If the problem persists, go to the next item
Settings or "features" on your smart TV could be causing these unintended power-the ups. We will work from more common to less common settings that could address the issue.
Each time you change a setting, you should give the unit time to see if the malfunction returns or if your setting change fixed it.
The biggest settings troublemaker. It lets other devices control your TV, and they will often be preconfigured to do it when they are being turned on. If you notice your TV turning itself on corresponds with use of another device, this setting is the likely culprit.
Disable it to prevent this from happening. It will prevent your remote from controlling other devices, but that is likely an acceptable tradeoff for control over your TV.
Another feature—this one connects your TV to the network that allows you to control devices throughout your home, but it also allows other devices to control your TV. A common device is your phone. You may be able to configure the settings so that your phone is not permitted to have control over the TV.
This can also cause random turn-on events. While we might think of a sleep timer as something to turn off the TV, it also works to turn it on! Disabling it in your settings is another step on the road to fixing the problem.
Another setting that frequently develops its own mind. It is meant to turn the TV off but can end up becoming corrupted and start turning it on. Disable it per your TV's instructions.
At this point, the next items to check are components on the power supply board of the TV. This involves opening the case of the TV. If you don't feel able to do this, you should bring the TV to a repair person.
The first place to check is the board controlling the IR Detector on your TV (generally near where the standby/power light is located). It is usually a small board. Since this is the board that sends the signal to the main board to turn on, it is the first place to look for "fried" components. Another check is to disconnect the IR board, and then see if the turn-on problem disappears. If the problem goes away, you know to replace the IR board.
The next place to look is the main logic board. The more frequent component failures are voltage regulators (often attached to a piece of metal on the board with a screw), and MOSFETs (transistors). Check also for swollen capacitors, but these are not as common on this board. If any components look damaged, replace the board.
A MOSFET on a TV PCB
Swollen capacitors on a TV PCB—the bulging tops indicate issues.
Power Supply Board
The last possible culprit is the power supply board. Especially as components like capacitors age and thermal cycle, they are more prone to failure. You should especially check the appearance of the capacitors on the power supply board and see if any are bulged. if they are you can replace them or if you don't feel sure or skilled enough, you can get a replacement power supply board.