LG 55" OLED Repair 55eg910t

Jackson on 09/12/2021 - 17:07
Last edited 10/12/2021 - 13:02

Hi Guys, I have the above LG OLED TV, it's 55" FHD in case anyone is wondering. It's completely dead, no LED. After popping the cover off and everything looking pretty new, I've check the main fuse on the smaller power board and it was faulty. After replacing the fuse and turning on the power point, it seems that on the secondary power board a *fast/ultrafast diode BYV10X600BQ fried. After replacing that, testing again, the same thing happened, specifically that as soon as I plug in and switch the power on at the power point, that diode smokes (I don't get to the point of turning on the actual TV)

I'm not a tech, I'm just a curious person, so I'm wondering if anyone has any advice. Some links to show the parts:

Small primary power board where AC plugs in: (this is the one that I replaced the fuse in the middle) https://www.aliexpress.com/item/4001099175161.html
Secondary power board where the diode keeps frying: https://www.aliexpress.com/item/32950706646.html
(for reference the diode that fries in the picture is under the heat spreader at the top of the picture, and is the one on the far left, you can see a bit of black on the heat spreader from where it burned.

Pictures of my actual board as requested: https://imgur.com/a/MStFqnA

Apart from general advice, as you can see the 2 boards are about 30 and 70 bucks respectively. What I'm wondering though is:

  1. If I replace the larger board first, is there a risk that either the primary board or a board downstream is causing this component to blow and not a fault on it's own board? I figure for the downstream ones I could just disconnect the ribbon cables before I plug in, but I can't unplug the primary board because that's where it's getting it's power from
    the diode didn't look blown when I initially checked the TV, it only blew once I replaced the fuse and then plugged it in. Hopefully that info might be useful.
  2. Otherwise I could try just fixing the secondary board again, and getting a new primary board which is the cheaper one, but then I might be out of pocket for both boards, which I'm trying to avoid

Anyway, I figures there's some handy techs here that might be able to provide some insight, or maybe worked on this TV before and know it's ins and outs.

Thanks for reading.

Electrical & Electronics 55inch LCD TV LG TV

Comments

  • spackbace on 09/12/2021 - 17:24
    -1

    Why would you go to that effort for a FHD tv, with the world of 4K tvs we have currently?

    • Jackson on 09/12/2021 - 17:31
      +5

      Not fussed about 4k, OLED is nice, save it from hard rubbish

    • diddy50 on 10/12/2021 - 08:42

      "the 2 boards are about 30 and 70 bucks respectively."

      spending $100 to fix the tv rather than $3000 to replace…

      I dunno why they would go to that effort….hmmmm

      • spackbace on 10/12/2021 - 09:43

        $100 plus personal time to fix a 1080p TV? You don't think it can get replaced for a similar amount on the used market? Plus there's no guarantees the time + money invested actually fixes it

        • brendanm on 10/12/2021 - 11:26
          +1

          4k isn't that special. A 1080p OLED or plasma shits on most 4k led panels for image quality.

        • Jackson on 10/12/2021 - 11:38
          +1

          I like to know the inner workings of things, plus the satisfaction of fixing something that was broken, with the fact that you are saving a bunch of electronics from landfill (because who knows how reliable our recyclers are?). Also I get to fix it with a friend, and we have a bit of fun solving puzzles. Plus it's not like it's a Soniq, this TV is among the best around for the time, even now if you aren't fussed about 4k. Oh and one more reason, this TV supports 3d, which I prefer to 4k, and they are getting harder to come by now

        • Jackson on 11/12/2021 - 10:24

          I did a quick check on ebay, cheapest 55" LG Oled was 1k albeit for a 4k model. People like these tvs and tend to hang on to them, even upgraders probably put it in another room

  • boomramada on 09/12/2021 - 17:30
    -3

    Out of the warranty, better buy a new one.

  • bazingaa on 09/12/2021 - 17:44
    +2

    check the path after that diode. may be shorted driver ? (or short could be on a 3rd board which is powered by 2nd board) also I think better to add photos of your boards so that some one can look for any blown out parts.
    primary board seems to have 2 bridge rectifiers and a switching mode driver, can't see the parts clearly though.
    so 2nd board is should be for generating multiple voltages for each component.

    • Jackson on 10/12/2021 - 13:03

      Hey mate thanks for the advice, I've uploaded pics of my board here https://imgur.com/a/MStFqnA

      Nothing actually looks bad apart from that diode. Only the fuses were tested and they seem good. I haven't checked the boards that are connected further down, one has a giant heat spreader on it so nothing was visible, and another didn't see anything that looked bad/burnt

  • Zio on 10/12/2021 - 11:28
    +1

    I have this TV and its awesome and totally worth repairing if you can - i recently bought a LG GX (as a newer second TV) and i honestly can barely tell the difference even with 4k Content.

    • Jackson on 12/12/2021 - 08:02

      Yeah it's not a huge TV so the 4k makes less difference than if it were say, and 86“. Specs actually say it's slightly under 55", something like 54 or 54.5".

      Do you have any issues with image retention/burn in?

      • Zio on 29/12/2021 - 22:17

        No problems at all

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