What To Do With A Broken Television When You Can’t Fix It

The AUO-manufactured controller board of an LG-branded TV. (Credit: Andrew Menadue)

Who can say ‘no’ to a free TV, even if it’s broken? This was the situation [Andrew Menadue] ended up in last year when he was offered an LG 39LE4900 LCD TV. As [Andrew] describes in the blog post along with videos (see first part embedded after the break), this particular television had been taken to a television repair shop previously after the HDMI inputs stopped working, but due to a lack of replacement parts the owner had to make due with the analog inputs still working. That is, until those stopped working as well.

The nice thing about these TVs is that they are very modular inside, as [Andrew] also discovered to his delight. In addition to the LG controller board, an inverter board and the power supply board, this TV also contained a TCON PCB. After some initial unsuccessful swapping of the parts with EBay replacements, nothing was (surprisingly) working, but it did turn out that the TCON and inverter boards are made and sold by AUO (major Taiwanese display manufacturer), along with the display itself.

In the end it turned out that the AUO boards and screen were fine, and after sourcing a board to convert VGA input to the LVDS signal accepted by the TCON board, the whole display worked. Naturally using a board with HDMI inputs would be nice, but it does show how a ‘broken’ TV can be turned into a really nice, big monitor without all too much effort if it’s just the controller board that went on the fritz.

Top image: the AUO-manufactured controller board inside the LG-branded TV. (Credit: Andrew Menadue)

30 thoughts on “What To Do With A Broken Television When You Can’t Fix It

    1. Pretty much. The controller board was replaced with a different one, so whatever post-processing features it used to have are now gone. Would be nice if the new board has its own post-processing algorithms, but it only has VGA input, which tells me it’s a bottom-of-the-barrel model with only basic features.

          1. It’s virtually impossible to find a large size (50+) consumer grade TV which is not Smart.
            That is a challenge BTW.

            That’s why I bought a commercial display. More inputs, more brightness, more settings for the picture, full RS232 control of everything, metal casing, longer warranty and better MTBF. And no smarts at all.

          2. Reply to dave:

            Walmart Sceptre brand are dumb 4k tvs with bog standard IPS panels. Often deeply discounted on the web site.

            Not great, not terrible. 60Hz. Speakers really really suck. No quality control, but just return to brick and mortar if you get a bad one.

            They also had a JVC on the web site recently. What I’m using at the moment. Worth the extra $30 for decent built in sound.

            On sale you can get a 50” dumb tv for about $200-250…until recently you could anyhow. Right now not on sale and asking $300+ for the 55.

            I wish they made a 40” 4K dumb TV. 50 is just a little too big.

  1. I’ve opened up an old Samsung TV that had a very similar TCON board to this one.
    Whatever the chip to the right is, it burned out twice.

    Recently I’ve also opened up a modern LG TV and there was no TCON board at all, the mainboard connects directly to the LCD drivers. So repurposing just the panel seems impossible.

    1. You can find lcd driver boards for small screens, which have HDMI inputs. I bet they exist for larger screens too, but I have no experience sourcing them. I think this tinkerer just went cheap and easy after so many frustrations.

    2. Indeed. Here in Brazil I have a LG 47LE7500 which internally only have two boards, the power supply and a a control board with integrated TCON, which failed and cannot be repaired. I still haven’t found a match for an external TCON. But I keep looking!

  2. It’s good that he didn’t give up after the replacement TV controller board didn’t work, and he went the extra mile by making a custom PCB to tidy things up. Thumbs up!

    Would be nice if controller boards are available for smartphone and tablet screens– have a dead Asus tablet with a 7″ 1280×800 IPS screen and would like to make use of it as a standalone monitor.

  3. I used mine as a sled!
    Honestly no I have a ~10 year old TCL that’s still doing fine, and that was the first LCD TV we bought (my first LCD computer monitor is a 18 inch 1280×1024 mitsubushi, its backlight is dimming out, but it was my primary monitor from Y2K to like geez 2013… now its on my G4 mac which gets run a few hours a week, like to get my return on that 1000$ for a monitor investment)

    1. Backlight is dimming out, sounds like cold cathode tube lighting. Find a cracked LED TV or monitor the same size and hack the 2 together. I have several worklight screens made from big screen cracked TV’s. It’s like a skylight anywhere you want.

      I’m ready to gut a working cold cathode screen to fit on an all-in-one that had gotten cracked but lights up nice and bright.

  4. It’s a sickness. I’m not even sure how many TVs I have around here anymore, and I can think of only one of them that I actually paid for. Monitors, too. I just can’t seem to pass up a display that someone is tossing out. They are just too easy to repair, compared to the CRT models I worked on at my first real job, but no one wants to pay for that. They used to be the center piece of the living room, in a position of pride. Now they’re just a disposable commodity, droning along as the family ignores them while they stare intently at their own personal handheld displays. Why do I even bother?

    1. I have working circuit boards and LED backlighting I pulled from a cracked TV. Nobody wants them for repair parts because the TV was a pretty old one, for the value of “old” in Smart TV years. IIRC it was from 2014 or 2015. No HEVC support, which any 4K Smart TV circa 2016 and later should have. Some 2015 4K sets did HEVC.

      If I could find out the voltage for the three LED backlight bars I’d build a fake skylight using the diffuser panels I kept out of the TV.

      1. They’ll be 3 to 6V for each LED. just count the LEDs in the strip and do the math. The button style strips are easy because they have only two leads. If it’s a surface mount LED strip and has more than two terminals, they’ll be powered in segments, so you’ll have to divide the total voltage by the number of segments, or jump the terminals to put the segments in series. I just take a reasonable under driving voltage and test the terminals one by one to see which terminals drive which segment. If nothing lights, reverse the polarity and move on to the next set.

  5. I have just started selling parts for an HD curved Samsun OLED TV, because I couldn’t get a mainboard at a reasonable price (cheap enough to risk it). So far sold the LED driver board with a big ALTERA on it. PSU board is next.

    I was wondering if I can still drive the OLEDs themselves for kicks, maybe a sculptural display or something, if I know what voltage to apply across which of the 4 100way ribbon cables, presumably 2-3V would do it. Unless there’s an active thin film transistor in the panel too?

    For the backlights above, start with 10V on a current limit and then crank it up slowly?

  6. Often LG TVs (maybe others) can be fixed by reflowing the solder by putting the main board in an oven for 10 minutes or so. Smells awful, but I’ve done it several times in the past few years to keep mine going. I think the problem is the repetitive heat cycles and badly laid out or mechanically fixed chips. It’s usually hdmi that goes first, followed by analog and sometimes sound too.

    1. Oh yes I did this too – cranked it up to the max (and made sure the wife was out) for a potential reflow. As there was nothing to lose, the mainboard was toast (now it’s roast!). The stink was pretty bad but the oven at least got the self-cleaning done.

      I used around 260C for about 10-15 mins then cracked the door open for a slow cooldown, and didn’t move it until it was below 80C or so.

  7. I always stock pile enough of my unwanted, uncraiglistable and/or way too broken electrical hardware to then cart it off to
    the town recycling center. Hopefully, it’s worth the effort, environmentally.

  8. I have a Philips 40PFL8007 TV with a dead motherboard. Was thinking about connecting the panel to some universal control board, but then I discovered that the LCD panel doesn’t use LVDS, but rather some newer standard called V-By-One. I cannot find a controller board with this standard (at least not cheap enough to risk ordering it from China ;) ). Does anyone know if such board can be sourced from somewhere? It’s a shame to get rid of otherwise perfectly fine TV ;/

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