Seiki SE50FY28 LED TV, no backlite

[budm]

Re: Seiki SE50FY28 LED TV, no backlite

I got the picture of the LED strips from shopjimmy which you cannot see in UK, but it is 100% for sure but base on the links I provided the same power supply is being used in the TVs also so it is more likely to be the same.
https://www.badcaps.net/forum/search...archid=6197969

TV made by the same OEM.
http://www.tongfang-global.com/Seiki.asp
Seiki
SE50FY28
Element
ELEFT502

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

All - Thanks for your help so far.

BUDM - Seems that link doesn't work for me (I'm in the US).

Per request, I am getting 123vdc from L+ (C11 red wire) to chassis gnd, and 23vdc across C11 itself. The 123v stays pretty steady, but as I mentioned earlier, the rest of them float up/down a little. Does that help?

And looking at the correct 'out-of-stock' LED strip from ShopJimmy, I'm wondering if it's a real representation of how many LEDs are actually on my strip (it shows 10 on 5 strips and 8 on the other 5). Comparing to other LED strips on their site, they're different so I think it may be. I may hook up a PS and see what I can learn.

What is the actual voltage across one of these type of bright LEDs? Are they like the run-of-the-mill v-drop? I'm new to them, so a bit cautious.

To be continued ...

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

... and here I am again.

No response by running up to 30v on each of the 5 lead-sets, and I get an open-circuit (resistance and diode-check modes) in both directions on all.

Y'all have implied they are driven in a series configuration, but I'm confused. Are they?

Going into the tv from the back, the two boards (PS and main) and associated wiring are on a single pressed metal panel while the red/white LED cables are bundled and go into a hole low on the metal panel. Same for the video cables. It looks like if I remove all back-panel screws and lift it off, I should be able to get to the LED strips on the back of the metal panel and then check directly.

How is the actual video panel (for lack of a better word, where the image is created) connected to the wiring? With LCD panels I've worked-on, they use the super-fragile TAB connections along the sides. Is this the same configuration?

Stay tuned (pun intended)...

[ReeceyBurger123]

Re: Seiki SE50FY28 LED TV, no backlite

Yes they are in series, you have an open cirucit in the Led strings. You need to take apart the screen to access the Leds to test them. Have you watched my video on how to test them ?

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

Thanks RB123. Yes, I did watch it last nite and again this morning... VERY informative! I just wasn't sure if your set comes apart like mine.

Thanks for your help, I'm going to try it now.

[ReeceyBurger123]

Re: Seiki SE50FY28 LED TV, no backlite

No problem, just be very careful of that Lcd screen when taking it out

[budm]

Re: Seiki SE50FY28 LED TV, no backlite

All - Thanks for your help so far.

BUDM - Seems that link doesn't work for me (I'm in the US).

Per request, I am getting 123vdc from L+ (C11 red wire) to chassis gnd, and 23vdc across C11 itself. The 123v stays pretty steady, but as I mentioned earlier, the rest of them float up/down a little. Does that help?

And looking at the correct 'out-of-stock' LED strip from ShopJimmy, I'm wondering if it's a real representation of how many LEDs are actually on my strip (it shows 10 on 5 strips and 8 on the other 5). Comparing to other LED strips on their site, they're different so I think it may be. I may hook up a PS and see what I can learn.

What is the actual voltage across one of these type of bright LEDs? Are they like the run-of-the-mill v-drop? I'm new to them, so a bit cautious.

To be continued ...

Per SJ, there are 10 strips total, 5 strips of 8 LEDs per strip, 5 strips of 6 LEDS per strip, you then link the strip of 8 and strip of 6 together to form a set of strip with 14 LEDs, then you link all 5 sets of 14-LED strip in series to form one large single strip, which as you can see, matches the link pictures of the exposed panel. So 30V is not enough to bias on 14 LEDs (14 x 3V = 42V) in series, and to be safe, you should use constant current source to drive LEDs incase there are shorted out LEDs on the strip.

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

OK, progress at last!

Took off the multiple layers of screens. When I got them all apart, I realized I had been holding my breath the entire time

As you can see from the 2 photos, there are indeed 5 strips of 6 LEDs and 5 strips of 8 LEDs, per budm and SJ (thanks!). Now, I at least know what to try and find somewhere.

Also from the photos, there are 2 LEDs that look quite burned and likely are a culprit. Haven't tested any of the other strips yet, but that's next.

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

Oops, the photos didn't get attached...

Can the LEDs be sourced individually? What are their ratings?

[budm]

Re: Seiki SE50FY28 LED TV, no backlite

BTW, when checking the boosted output of the LED power supply DCV (L+) feeding the LED string it should be checked with ref to the chassis GND.
Just another failed LEDs as usual, beside having open circuit LEDS, you should check all the LEDS to make sure there are no other open LEDs or shorted out LEDs.

[ReeceyBurger123]

Re: Seiki SE50FY28 LED TV, no backlite

Are those Leds failed ? Lol just messing you can substitute them with diodes or resistors but if you want the Tv to look even half decent you should replace them. You can obtain strips off ebay or I think someone had the link to the Led type used will try find it. Also you need to test every Led with your meter as it might not just be them two.

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

LEDs bad? Nawwwww. Reminds me of the joke about testing kitchen matches... "Yup, that one worked. That one worked, too."

Checking eBay now, but having a lot of trouble finding a match.

Just for grins, I may try the diode jumper. Are these regular voltage/current LEDs? Haven't got any of them to light up at all.

[dick_barton]

Re: Seiki SE50FY28 LED TV, no backlite

Flocko, forum member, sells several types of replacement leds.

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

Follow-up...

Good news: I found a replacement LED strip and installed it, and the LEDs now all light up.

Bad news: screen is cracked. I dunno if I did it during the surgery, or it was like that and I never noticed it. In any case, I get a very good picture on one side, and just lines or white nothing on the other side.

Any ideas? Can replacement screens be had?

[ReeceyBurger123]

Re: Seiki SE50FY28 LED TV, no backlite

Doh ! What a shitter, finding a replacement screen is almost impossible and not worrh it

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

Kinda what I suspected/feared.

Oh well, I now have a lot of working parts for a Seiki SE50FY28 LED tv (except the LCD screen ), if anyone needs anything.


Thanks y'all for your help!

[dick_barton]

Re: Seiki SE50FY28 LED TV, no backlite

Follow-up...

Good news: I found a replacement LED strip and installed it, and the LEDs now all light up.

Bad news: screen is cracked. I dunno if I did it during the surgery, or it was like that and I never noticed it. In any case, I get a very good picture on one side, and just lines or white nothing on the other side.

Any ideas? Can replacement screens be had?

Out of curiosity can you post a picture of how the screen now looks.
Thanks

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

Uhhhh, would that be before I threw the $#%@! thing out into the canal or afterwards?

I'll get them for you tomorrow, I'm not ready to go near it again tonite.

Wife said she thinks remember seeing the entire NO SIGNAL caption when we were doing the flashlite test, and before I disassembled the screen. I was only interested in seeing if anything was showing or if was all dead.... at least that's my story!

[dogdad]

Re: Seiki SE50FY28 LED TV, no backlite

Sorry for the delay. I was so frustrated with the thing, I didn't want to look at it again for awhile (a looooong while!).

Anyways, here's the requested photo. As you can see, it's in great shape on the left side but not so good on the right (well, duh). If I wiggle the screen just so, I can get colored lines within the white area on that side, which means the rest of the electronics/etc is working - except for the discontinuity at the crack.

I found the tv alongside the road, so i don't know its past history. But in thinking it all over again, I'm pretty sure I cracked the screen while working on it - no idea it was that thin. Almost felt like it was plexiglas at first, because it can bend..... A LITTLE.

I am so disappointed in my failure that I have been seriously considering going out and buying the same tv (found it online for $299), and putting the new screen back in this chassis. How's that for stubbornness?

I've been searching for a replacement screen, but as expected it's no joy. eBay'ing the parts is probably the next step. Does anyone know if online places (ShopJimmy, etc) are interested in the stuff?

Thanks for all your direct help, guys, as well as for the forum in general. I've learned a lot!!

[vinceroger69]

Re: Seiki SE50FY28 LED TV, no backlite

I wonder if this could be a tab bond issue? rather than a crack?