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Question

Samsung UN55H8000 Sound but no Picture

Jul 24, 2016 3:07PM PDT

I have a Samsung UN55H8000 and get sound, but no picture. I changed out the TCon board, but still nothing. When I turn on the tv, the picture came on, then half of it went, and then it all went. I was able to reset the tv, but still nothing. I unplugged it for about 12 hours, and still nothing. Any suggestions would be appreciated.

Discussion is locked

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Answer
Be sure
Jul 24, 2016 3:26PM PDT

To get a service manual. The TCON board is what I see folk that read the internet try all the time. You need a service manual, basic tech gear and not be new to TV repair. You also know TV repair discussions are very rare.

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Answer
Same issue
Jul 29, 2016 12:08PM PDT

Mine just had this happen a few days ago as well. Was new in Dec. 2014, it seems to be a widespread issue. I'm trying to find a service manual to download now, but I saw a youtube video of someone with the same issue except his was intermittent at first. He answered my comment that, for him, it was the "backlight power supply." If I can't narrow it down troubleshooting that'll be my first part to shotgun. Please let me know if you figure it out and i'll do the same. Thanks

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Found the manual.
Jul 29, 2016 12:44PM PDT

Post was last edited on July 29, 2016 7:45 PM PDT

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Manual
Jul 29, 2016 6:47PM PDT

That's the one, thanks for posting it. I think i'm going to give it a shot.

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Edit
Jul 29, 2016 6:59PM PDT

Edit*
Never mind, having to pay 5.00 s/h pushed me over the edge. Thought I could just download it. Not sure what I'm going to do besides maybe try that power supply.

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Did you work back when there was ....
Jul 29, 2016 7:47PM PDT

Sam's PhotoFacts?

Those were usually much more expensive but that was then, now is now.

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Service Manual Download
Jul 30, 2016 4:26AM PDT

I found a downloadable service manual. It was $14.95 -- up until last night, when the price went up. Here is the link:

278979127-samsung-un55h8000-un55h8000af-un55h8000afxza-service-manual-and

I have yet to download it.

Question: Does anyone know where the backlight power supply is located on this tv? I took the back off to look, but have no idea what I am looking for. Have also seen YouTube video that says it could be backlight inverter board (saw nothing that looked like this when I had the back off), or the LED driver board (didn't see that either). If anyone knows where these are, can you please point me in the right direction?

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Sorry no.
Jul 30, 2016 7:20AM PDT

That would be in the service manual but so far it's split duty between the main power board and the board that connects to the LED.

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Answer
Downloaded the Service Manual
Jul 30, 2016 9:04AM PDT

Bit the bullet, paid the $17. However, it is not as easy as I thought it would be. Trying to figure out where everything is located and what everything is.

The download includes PowerPoint presentation showing the lay-out of the tv, and I am picking my way through it now.

I don't know if I can do this on this board, but if anyone wants to take a peek at the manual and point me in the right direction, let me know and I will try to get it to you.

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What do you mean "do this on this board"?
Jul 30, 2016 9:12AM PDT

Board repair is usually never done. You swap boards and the manuals usually tell you to swap boards. There are old school techs that did and still do board level repair but without spares, schematics and a whole lot more, we are now in a board swap system.

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Clarification
Jul 30, 2016 9:24AM PDT

Sorry -- I meant on the posting board. Most other boards don't let you exchange information using their posting boards. I did not mean any board inside of the tv. My apologies for any confusion.

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These manuals are
Jul 30, 2016 9:45AM PDT

Copyrighted and not shared. While I do use such to do repairs, I'm an electronics designer which means I am a few levels up from a tech. So what do I do when I get a broken device? If it's something I can't google or just know about, I'm off to find a service manual.

HOWEVER there are costs to keep in mind. The shop min charge is 150USD so that means that if it's some hundred+ buck board, the set is usually not repaired as the price of new sets have fallen.

Example. Amazon has 3 55 inch models in the top 20 best sellers at 450 to 550 USD. So an old failed TV and a 250 or more repair bill usually means folk send it to recycle centers and replace.

-> Here you think you know what it is, so you use the manual for the guide to which board.

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Your opinion
Jul 30, 2016 5:53PM PDT

R. Proffitt, looking at the service manual and reading voltage at all the locations it describes on the power board, all the voltages look to be correct and I was also able to force the backlights on. This makes me lean towards the t-con board, which the manual also says under the first step for testing "Check 3 LED indicator for operation (all on when OK)" and I only have 2 blue LEDs on currently with LED03 being off. Would you agree the problem is most likely the t-con board?

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It's either that or a bad
Jul 30, 2016 7:39PM PDT

Panel where the LED is or the connection to said LED back light. They don't provide schematics so it's usually a guess at which board. TCONs are usually too cheap to bother guessing. A tech would swap.

Post was last edited on July 31, 2016 1:11 PM PDT

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Update 7/30
Jul 30, 2016 5:40PM PDT

I actually downloaded the manual as well last night after some further searching. Not quite what I expected but some good info at least. After looking at the manual and my own troubleshooting I think I changed my mind to the Tcon board. So if you want to sell your old one that probably works let me know haha. Something I noticed than saw later in the manual; if you unplug CNM803 from the "SMPS" board and then plug in your set, does your screen turn white (forcing backlights on)?

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One last thing to try
Jul 31, 2016 12:56PM PDT

I took the back off, and it looks as if not all of the LED's on the TCon board are lit. According to the manual, if that is the case, the LVDS cable needs to be replaced. I have ordered a new one.

I don't want to sell you a bad TCon board -- however, as neither have worked, I don't believe there is anything wrong with either of them.

I bought it off ebay for $60, so I would sell to you for the same price. Lesson learned.

What really sucks is that I bought a new tv as I thought this one was shot for good. The new one is due to arrive tomorrow. I am going to keep it in the box and return it if I can get this one up and running.

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Answer
Update -- TV Finally working!
Sep 16, 2016 6:04PM PDT

Okay, so I changed out the Tcon board, nothing. Changed out the LVDS cable, nothing. I was frustrated beyond belief. I contacted someone to come to the house to fix it as there is no way that I am attempting to get a 55" in my car by myself! He came out and did some troubleshooting, and it turned out to be the main board. He gave me the part number and where I could get it. He said that for him to repair, it would be about $700. I ordered it, replaced it, and voila -- I have my curve back!!!!

Have a Tcon board and LVDS cable for sale if anyone is interested . . . . .