Samsung UN55KS8000FXZA Won't Power On

Th3pwn3r

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Aug 29, 2011
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Hello, all I'm posting this here in the event someone else somewhere has the same issue.

So it all started when the TV was powering itself off randomly, I didn't think much of it, I would just turn it right back on, it was annoying but eh, I lived. Then it got to the point where I'd have to pull the power cable out and plug it back in for the unit to turn on again. After about a week or two of doing that the unit powered itself off and never came back on, pulling the power cable out and plugging it back in no longer worked. I'd like to add, there's no power LED coming on at the front of the panel, no sort power being used or indication the unit has power. I may split the power cable apart tomorrow and read how many amps are being drawn with my Fluke multimeter, my guess is 0.

I figured the power board went out. I came across lots of threads where caps had blown and that was the culprit. Well, long story short, I bought this TV used on Craigslist and was told I had a 60 day warranty, problem was, I couldn't risk shipping the TV because he couldn't insure it due to not having the original box. That brings us to how I ended up with two of these same TVs, one is a broken screen unit that powers on, the other has a good screen that doesn't power on. A simple swap of the power board should have my unit with the good screen working, that didn't work.

So I swapped the power boards between the TVs(both same model to remind you) and the unit with the broken screen powered right up. That ruled out the power board(I forgot to mention visual inspection revealed no blown capacitors, a digital multimeter also showed no issues). Then I figured it had to be the main board, I swapped the mainboards and STILL, the unit with the good screen didn't power up. At this point I had swapped the mainboard and powerboards between TVs, the unit with the broken screen powered right up with the parts I suspected to have failed. So I'm somewhat confused at that point. Then, wiggling things around, the TV with the good screen powers up! I then attempt to flip the screen upward(it was screen side down) to get a look at it and it shuts off instantly.

That's where I have left off, I think there may be a loose ground within the unit. The other thing I'm thinking of is that there's a problem with the wiring within the plastic speaker housing, perhaps there's an small amplifier in there that is causing an issue. I also swapped the power buttons between the units to rule that out as well. I noticed a very small hum that I could eliminate by tapping around lighting on the area of this speaker housing, that's why I suspect a problem inside there. The noise can also be shut off by disconnecting a small two wire harness/jumper that branches off of the main power switch and runs into the speaker housing I have mentioned.

The habit of not being able to leave things unsolved in me wanted to keep working on the TVs but I had to go and pick up my daughter. Tomorrow I will dig deeper into the hardware of these TVs but at the moment I have disclosed everything I've tried. I have also pulled the batteries out of the remotes to avoid any sort of foul signals causing me problems. I wlll update this tomorrow.

Again, this is mainly being posted for awareness. I did quite a bit of digging and didn't come back with much information, just more questions really. Hopefully this will help someone out there, who knows, maybe somebody here has some sort of advice or is familiar with this when it comes to TVs.

Thanks to whoever read this!
 

Th3pwn3r

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Aug 29, 2011
257
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18,860
Alright so I have solved the problem. I removed the speaker frame/housing and my suspicions were correct. There was a shorted wire. Samsung did something really stupid and taped the power wire feeding the front panel to a sharp rivet. I will try to figure out how to upload a picture here but I'm kind of clueless -_-

Samsung%20Pic%202_zpsqjz0lsap.jpeg
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Samsung%20Power%20Wire%20Short_zpstgrrdjl7.jpg
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In this pic above you can see a small shiny spot on the black wire, it's hard to see it but if you look closely it's there. When this wire shorts out it will turn your TV off. Mine was shutting off by itself and I had been turning it right back on. Eventually that wouldn't work anymore and you know the rest.
 
Jun 16, 2019
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So Samsung says the “rebooting” of some of their TVs is due to the TV detecting problem and attempting to fix it by rebooting.
My 2010 Plasma started rebooting so often, I was afraid to try to update the software. In my situation there was no dust in the TV to speak of and all the capacitors looked fine. Software/firmware got updated to the latest.
Another comment on another site said they checked all the ribbon connectors. Once the back panel was off, of the dozen or more ribbons, I found maybe two that were a bit loose and pushed them back in.
Problem solved.
Then I remembered what happened. Earlier that day I had the volume up to the max for the first time ever because there was so much noise outside from construction I could not hear the TV.
The loudspeakers must have vibrated some connectors loose.
Okums razor. I wonder how many people spent money only due to a loose connector.