Samsung UA40D6000 UNIQUE back light issue!

[mgp32]

Good afternoon everyone. A buddy gave me a Samsung 40" LED (UA40D6000) tv a couple years ago because the back light intermittently goes out on it and he was sick of dealing with it so he bought a new tv. I use it as my garage TV but I seem to spend more and more time in there so I think its about time I try to fix it.

The Unique thing-The backlight doesn't go completely dark, it just gets really dim. Ive tried searching this for quite some time on the internet and it seems when the backight goes out on Samsungs they get almost completely dark. When I have the lights off in the garage at night I can actually see the picture pretty good but when I have the light on or when Im watching during the day it is very hard to see. I can usually get it to come back to full light buy giving it a slap on the back of the TV or wrapping the sides of the tv with a knuckle.

I also should note that the TV rarely goes out when its cold. When I'm viewing during the winter or fall it rarely goes out but now that its warmer it goes out quite frequently and most the time I will not be able to get it to come back to full light by tapping on it.

This leads me to believe it is most likely a bad solder joint but I figured I would ask you experts. Would you agree with this? If so, could you point me to a particular board that you may think is suspect? Any other advice would be great as well.

Thanks everyone!

[budm]

Re: Samsung UA40D6000 UNIQUE back light issue!

I does sound like bad connections, so look closely at the power supply/LED driver board especially around the transformer legs solder joints and the solder joints on legs of the devices mounted on the heatsink. Also tighten up all the board mounting screws.
Any pictures of the boards and the whole back side of the TV?

[mgp32]

Re: Samsung UA40D6000 UNIQUE back light issue!

I do not have any pictures at the moment but plan on taking a look at it this evening when I get back from work. Ill post up some pictures if I can't get it.

[mgp32]

Re: Samsung UA40D6000 UNIQUE back light issue!

I was unsuccessful but I'm about %99 sure that the problem is somewhere on this board because I ran the tv with the back cover off and when tapping on this board(with a non-conductive object of course) the backlight would try to come back on. I couldn't pin point it to a certain component though.

I did touch up a few solder connections that around the transformer that looked a little iffy but this didnt help at all.




What percentage would you give me that this board is the culprit? I'm fairly this board is bad from what I seen when tapping on it but you never know. Im thinking about putting an offer on a board from a guy on ebay but I dont want to throw $40 down the hole if this isnt it.

Any more help would be appreciated!

[mmartell]

Re: Samsung UA40D6000 UNIQUE back light issue!

Use a hair dryer to heat up small sections of that board to see when the backlights come back on. If you have a bad joint the expansion caused by the heat may force contact. I have a dryer with the cardboard roll from toilet paper taped to the end of it to limit the area of heating. Good luck.

[mgp32]

Re: Samsung UA40D6000 UNIQUE back light issue!

Im thinking heat is whats causing the connection issues. In my first post I mentioned the TV works WAY better during the cold months of the year and barely goes out. Now that its hot out the backlight is out the majority of the time.

[newtothis]

Re: Samsung UA40D6000 UNIQUE back light issue!

Heat causes expansion and cold contraction, If it were a bad connection cold would actually pull it further apart.

If tapping it makes a difference make sure all grounding screws are clean and tight.

Use the hairdryer as mentioned anyway to see any results, If that doesn't work try using freeze spray to cool the board instead

[vicvc]

Re: Samsung UA40D6000 UNIQUE back light issue!

interesting material on led backlights in thread about ua32d4003bm....

[budm]

Re: Samsung UA40D6000 UNIQUE back light issue!

"I did touch up a few solder connections that around the transformer that looked a little iffy but this didnt help at all." I would do that to ALL the legs of the transformers and the power devices.

[mgp32]

Re: Samsung UA40D6000 UNIQUE back light issue!

I may be jumping the gun but I put an offer in for this board from a guy on ebay and I got it for $25 shipped. All other sellers want atleast $90+ shipped. Hopefully this will correct it!