Samsung UN55D6450 turns itself off and on endlessly, no blinks

[nroberto13]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Hi Guys, back with news. Replaced my main, but unfortunately just noticed that the top of the screen is not lit, so I guess during the different testing so many reboots ( each one triggering the leds on and off ) burned the leds..., I'm pretty sure when the TV started to reboot, the screen was equally lit everywhere. Now with the new main the tv behaves slightly different, it doesn't turn on right after plugging to power, as it did with the my main, but it goes into standby and turns on only by pushing power button. I've tried with 2 different power boards and backlit is the same with both. Tried to disconnect the led's connectors, but still the same. Is there a way to test the leds?

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Got the led strip yesterday (thanks!) and had it all modded up but had some difficulty with figuring how to cleanly connect it to the panel. Still needs a little work. I only jumpered the one burnt led as I didn't have any luck removing any led's from my old board. Fired up great during a brief test run.

Will update with a pic once I get the strip mounted.

[withalligators]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Yeah, not related to my/our issue. Mine could never start because it would endlessly try and get past a physically shorted LED (which it never could).

mmartell, how's it going with the LEDs?

[tom66]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Looks like a bad main board - possibly BGA soldering failure. Also possibly a bad power board due to cold solder joints or other failures. It'd be best to open a separate thread for a different problem so we don't get mixed up.

[nroberto13]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Thanks for the quick replies,

@freakaftr8, I was thinking that my issue is related to this one and didn't want to open useless new topics. Regarding the cooling, I'm not sure if it's needed, as if I leave the TV overnight and start it next day, it will behave the same way, bootloop for some minutes and then works 1-2 hours.

@tibimakai, How do I know if it's firmware related? I recently updated the firmware to version 1029. and after 1 day of working fine, the TV started too behave as described above. I tried factory reset, downgrade with samygo install 1025 again, all went succesfully, but TV behaves the same way..

[tibimakai]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

If it is firmware related, then most likely it's bricked and you need a new main board.

[freakaftr8]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Hello Norberto.
Welcome to the forum. for best results I would start a new post instead of entering your problem into this post for best results.

As for your problem the first thing I would do is try to get a can of freeze spray and first try to cool the power supply and see if the TV comes back on When it is acting up. if that doesn't help it is time to take some voltage readings.

Hi Guys.

I'm facing the same issues with my UE40D8000 TV, it restarts ( but not endlessly ) for some minutes then it turns on, works for around 1-2 hours and then goes into restart endlessly. I'm thinking about something related to heat? here's a short video of the bootloop behavior: http://www.youtube.com/watch?v=AdYjrU_B7Jw.

Any ideas how to solve this?

Thank you!

[nroberto13]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Hi Guys.

I'm facing the same issues with my UE40D8000 TV, it restarts ( but not endlessly ) for some minutes then it turns on, works for around 1-2 hours and then goes into restart endlessly. I'm thinking about something related to heat? here's a short video of the bootloop behavior: http://www.youtube.com/watch?v=AdYjrU_B7Jw.

Any ideas how to solve this?

Thank you!

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

I've tried hot air already. Seems to make the material covering the led itself come off easily once touched.

[tom66]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Looks like ceramic substrate with metal core, and yet they still overheat. I'd use hot air, if available. Cover the LEDs you don't want to remove with foil to avoid damage. You usually don't care about preserving the dead LED.

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

I cannot. I can't tell if the heat is being wicked away but I do damage to the led long before anything comes loose. In fact nothing comes loose at all. I will try again later. But if that doesn't work I'll probably look at sawing into smaller working strips and replacing them that way.

Here's an edge on look

[tom66]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Can't you desolder the LEDs?

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Well that's not too good then...

[tom66]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

This looks like a metal core PCB. It is probably not intended to be disassembled. The metal heatsinks the LEDs directly. The top side is probably ceramic which is a good thermal conductor. The two halves are probably bonded with thermal adhesive.

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Wow has anyone taken one of these off ? I am butcheting my board and they won't budge.

Here is a pic of the underside of the strip when you take it off the rail/heatsink it is screwed to. Maybe these numbers mean something to somebody (or google lol)

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

I will take one off mine maybe tonight.

[Ltank]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

All electric parts have some type of marking. Sometimes a code that you must lookup online to determine what the part is. Top,Bottom or Side they are marked. So a Pic would
be great. If remove the bad LED and take a pic and or tell us the markings we can locate the part..thanks

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Is there writing on the underside ?

[Ltank]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Glad for you. Curious about the LEDs that are soldered to the old boards that were removed from the set. Could you unsolder one LED from board and take a pic of the
markings so others can buy individual replacement LEDs in case the strips are not available. I have a set that may have same issue and I could build a test LED strip.
Thanks

[withalligators]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Ok, John's LED strips arrived and I tore the panel apart and inspected the LED strips. Sure enough, the left side (facing the rear) had a burnt out LED just a little up from the bottom. I swapped out that side and powered it up. Both sides lit (HOORAY!). I put it back together and now have a working set. All you folks who suspected a faulty LED strip should take a bow, you were right and I would have saved a lot of trouble had I just listened from the start.

So, now that's all back together I have horrible flashlighting on a black screen. I guess it's from separating the various diffuser layers. Has anyone had any luck fixing this? I was thinking of taking off it's bezel and laying it on something vibrating like a washing machine or something. Terrible idea?

Notes from disassembly: the black tape isn't structural, as there are plenty of screws hidden under it. It is to prevent light leakage though, and when assembled without it, you can see the silver screws through the clear bezel as well as light.

I have a left over LED strip from the right side, if anyone wants it, PM me.