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Samsung Smart TV keeps clicking on and off in a cycle

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Hey, so I have an issue with a Samsung tv un55ru7100fxza. It has this clicking sound and it’s in a cycle of turning off and on, you can see the startup logo for just a second before it turns off and on again. Almost every video I’ve seen so far talks about checking for bulging/ leaking capacitors but all the capacitors look fine and the solder joints on the back aren’t cracked or darkened. Next step is to take out each individual capacitor and test them which I really don’t want to do at all but I need to find the issue. I tried plugging in different boards to see if a particular board was causing it and I noticed that when I unplug the t con board the clicking stops and the tv stays on and I can manually turn it off, then I try and keep the t con board in and just unplug the 2 connectors that goes into the panel and the clicking continues, I feel like I need to replace the t con board but when I look up the symptoms of a t con board failing the tv just has fading or color distortions which I don’t have. So I’m kinda confused on why it would only click when that board is plugged in, if it was capacitor or power board issue wouldn’t the power board be clicking even if everything was unplugged? Awhile ago it’s done this but only for about 3 min then it worked fine and even for a week or two, but now it’s always doing it. I don’t know what to do since everyone I contacted wants hundreds of dollars to fix it. Is there anything else I can try?

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Hi @d3vn8tr ,

Do the TV screen backlights stay on when you remove the tcon board and switch on the TV?

If not, disconnect the power from the TV and reconnect all the boards as per their normal connection. Then disconnect the cable between the mainboard and the power board and reconnect the power to the TV.

The backlights should turn on and stay on. There will be no picture because the mainboard is disconnected.

If the backlights blink or don’t turn on then there is a problem either in the power board, the connection between the power board and the LED array or in the LED array.

Measure the voltage at the LED power connector on the power board. If the voltage is >250V DC then the problem is in the LED array or the connection to the LED array. If the voltage is <50V DC then it is in the power board

If the backlights turn on and stay on, then measure the voltages on the power board connector that the mainboard cable was connected to to see if they are OK. The voltage values should be printed on the power board near the connector. If the voltages are OK it may be in the mainboard.

Be safety aware when working in the back of a TV with the power connected as there is exposed lethal voltage on the power board near to where you will be testing. If you don’t know what you’re doing then don’t do it.

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Thanks for the response. Yes, when I remove just the t con bard the tv turns on and backlights stay on ( the full screen isn’t white though, there are bars of light on the top and bottom.) when I tried to just disconnect the main board initially it stayed on with full white screen, but once I tried it the next few more times the backlight just blinks and power board clicks. Where would I put multimeter points to test the backlight? There are 2 connectors with 1 that has 2 blue wires rest white and the other which has 2 black wires and rest white.



Just to make sure that I'm looking at the correct board either post a close up image of the power board showing the connections and the board number or post the board number back here.

Here's how to post images on ifixit Adding images to an existing question.

There are normally more than two strips of LED backlights in a screen though, so that is strange that only the top and bottom light up. Maybe there is a problem with the other strip(s) and that is why the power board clicks

Usually Samsung board numbers start with BN44-



I added those pictures. Ya, I don’t know why only 2 strips would light up when the t con board is disconnected but when everything is in all strips light up but obviously with the clicking on and off. The board number is BN44-00629A



The backlights should not blink. They should stay on or that's how it used to be. Things are getting more complicated ;-)

Looking at the images to me (and I'm not sure) it appears that there are feeds for Left and Right strips note the R and L numbering so maybe there is more individual control of the lights

Maybe there are two distinct feeds for each half.

If both sets of wires head into the screen then this may be the case but I'm not sure

maybe you could try a cheap backlight tester to confirm that there are two feeds and that all the LEDs are working OK. The TV does not have to be powered on to use it

Alternatively source a replacement power board from a supplier that offers returns for only a small restocking fee to minimize the cost if it is not the problem. A quick search online reveals a kit which to me seems to indicate a known problem with the board



I have added a few videos showing the issue I’m having. Maybe it might give clues for the power board issue or led strips, worth a try. After looking up some info on the tv I have found that it only has 2 led strips being on the top and bottom as you can see in the vids (but I could be wrong). I don’t know much about this stuff and would like to, is the dimmed lights due to the power board not providing enough power to the leds or would this be the led strip? The first video shown has only the 2 led connectors into the power board ( logic/ main board disconnected), second video shown has only the t con board disconnected, third video shown has everything connected.


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