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RandomVideos It's true watching Dave talk about electronics and explaining things makes it so much easier to understand electronics. When I started watching Dave's videos for the first time I didn't even know what those round pads on the pcb's were. turns out there Fiducials. And well thats a thing I'll never forget now.

RandomVideos Glad to hear, thanks! Similar to when I was reading electronics magazines when I was 8. I didn't know what most of it meant, but then years later it all clicked and WHAM came all the knowledge in a flood.

Yeah, he is a good engineer and explains things well but his repair videos always seem to end up making me cringe! :) Usually accompanied by a few [facepalm]s and shouting back at the screen in anguish... :) Keep up the good work, though, Dave!

+EEVblog Just like me you are Dave! I had boxes and boxes of pulled apart stuff under my bed when I was younger, I only realize now what I actually had and what I could've made with it :/ Never too late to get back into it :)

mikeselectricstuff It seems doubtful that anything is addressed by column in a way that would break things across the whole column before *and* after the text except for something related directly to the panel. I'm somewhat familiar with how this failure mode might occur with OLED panels, but I'm not that familiar with LED panels. With OLED panels, you need to reset each element to a certain voltage before writing a new scanline. It would seem here that something about each vertical column isn't getting reset between scanlines and some voltage or charge is building up across the whole column. And it's panel wide.

mikeselectricstuff That's what I was going to check with the scope if I get around to it.

I had a similar issue with a tea damaged LCD panel from an iPhone 4, but it was more in the opposite order. The panel would start up fuzzy and eventually clear up after being on for ~10 minutes. Some characters made bigger lines to be displayed as well. It has 3 chips on the panel(chip-on-glass?); two drivers apparently for each side of the long edge, and the wide chip tcon/short edge driver. The LVDS bus is fine and then phone has no issues with a new screen.

Definitely something floating...

Gustavo Ferlizi Are you British? Surely you gotta be British if you managed to damage an LCD panel with tea.

Green Silver It's always funny when it ends up being 3 dollars worth of capacitors. I think they've caught on that people are fixing these issues easily, so they've stepped it up to corrupting something or just having the chips shit themselves after a while.

It is easy to make a chip die prematurely. In the NMOS process, a little too much boron in the glass passivation layers will slowly cause the boron to slowly diffuse into the chip substrate, killing the chip. This was the problem MOS Technologies (Commodore Business Machines) had with the chips used in the C64. As they heated up (they ran hot) over time that made them diffuse faster and faster.

can you explain for me a little more please ?

Dwwd

Dwwdd

mikeselectricstuff Not the first time Dave forgot pixels have rgb elements.

mikeselectricstuff Err, yeah, Doh.

+Gone Tomorrow I would assume mobile phones have a lot more on glass logic to get passed that.

***** but its not only theirs 3 color for each pixel but you also have two lines correspond to each subpixel and a transistor in the corner.

EEVblog I may sound like an amater , but does the smaller BGA on TCON board looks like it's gone...? Looks like it's burned out... Warped... Shines more than the big one?

I have to agree, hook a Pi up to it, and check if it's just the menus, or full video problems

dreamfox32 Now that could be useful in isolating the problem. If it completely clears, the "character generator" could have a fault, or the connection from it to the next stage in the video processing. I imagine it's not a separate chip but integrated onto one of those custom jobs on the "processor board" as we're calling it. If I had to guess I would say those chips are not going to be available and full board replacement would be required.

dreamfox32 Did you miss the test image in the previous video?

hendik hendrik Wasn't the image test was generated by the processor board, and not by a completely external source?

dreamfox32 How would that repair the fault?

What’s the fix

Danny Bokma Yeah, I like the idea. It could have more educational value than a repair, and maybe more spectacular results.

nativewinner Spectacularly smoky and then the fire system kicks in :)

There have been up to now 10.000 people including Dave and David learning and being entertained from this dumpster-dive TV. Not sure if there's a way to get more bang for the (zero) bucks. ;-)

dreamfox32 Well, it _might_ be reasonably tolerable, but even if the image produced is flawless, I think that would be to miss the point: to make an interesting electronics repair (attempt) video. I don't think Dave is hurting for TVs. If that was mine I would probably just leave it at the appliance recycling place, and buy a new and better TV. They are so cheap now that they're practically disposable. That said, my 40" Sony LCD from 2007 is running like a champ. It's 10cm thick, but I'm not looking at the edge of the damn thing. :)

Good thing you mentioned that, just like Dave 2

Danny Bokma Exactly.

Danny Bokma Is there anything wrong by getting a second opinion? I have real experience repairing TV's, which Dave or Dave2 does not seem to have.

you had the same explanation, and of course there's nothing wrong in that.

***** Yes, that's the conclusion we came to. That's why I then reflowed the T-CON board.

+Light Man Yes, Don't batterise, analyse!

GadgetUK164 There is also a very plausible theory about the gamma buffer or other analog drive system at fault.

+EEVblog Interesting. When are you going back to it to find out?

on tcon board level it will always fit exectly the same way in memory.

Yes, as it's behind the scaler board. If it was a memory error i wouldn't appear slowly like that, but be there from the beginning.

Coolkeys2009 Knowing Samsung, they probably put put a counter where after a certain number of hours of screen on time, it corrupts some config in the firmware of one of the chips, or some other form of planned obsolescence.

+Razor2048 this is possible I remember when Epson printers did this

Razor2048 I can believe it was caused by a problem they missed or something they skimped on but I don't believe Samsung would bother spend the extra money to design in a fault. LOL

Carbon cricket FX This would actually be the stupidiest thing a manufacturer could ever do. Planned obsolence at the expense of staining brand quality just means a swifter way to bankrupicity.

Crimson Sunrise i know but they genuinely did after a set number of prints they said they needs servicing mine did www.reportsfromearth.com/155/designed-to-fail-planned-obsolescence-in-printers-tricks-to-fix-them/

Sometimes using this method you can get rid of the lines while retaining a good picture, also one of the ics on the tcon will be red hot while that shorts connected to it, that's why the lines slowly appear as the ic starts to struggle with the overload and the chip heats up

Brandon MacEachern Phase inverting?

Ian Oliver www.techmind.org/lcd/ "Inversion In liquid crystal pixel cells, it is only the magnitude of the applied voltage which determines the light transmission (the transmission vs. voltage function is symmetrical about 0V). To prevent polarisation (and rapid permanent damage) of the liquid crystal material, the polarity of the cell voltage is reversed on alternate video frames. Unfortunately it is very difficult to get exactly the same voltage on the cell in both polarities, so the pixel-cell brightness will tend to flicker to some extent at half the frame-rate. If the polarity of the whole screen were inverted at once then the flicker would be highly objectionable. Instead, it is usual to have the polarity of nearby pixels in anti-phase, thus cancelling out the flicker over areas of any significant size. In this way the flicker can be made imperceptible for most "natural" images."

+Brandon MacEachern So where exactly is the culprit on the boards?

+Protonus And? Did you fix it?

The Kaiser Sort of! The caps were certainly bad. 1 in that value was visibly bulged, one read a high ESR, the other 2 I replaced anyways. But it didn't fix the picture issue, just make it stop changing with temperature. So I found that one of the ribbon cables, going between the actual panel and the driver boards at the top of the display, was faulty. If you apply a bunch of pressure to the cable itself, to push it up against the metal frame of the TV, right where that tiny "chip on ribbon" cable is on the short cable, it would restore the picture to about 95% perfect. All the vertical lines and bars, and color bleeding go away. Most of the horizontal lines go away too. The one that was bad is the left most cable for this particular TV. I hot glued the small/bottom end of a small (3/16" thick?) rubber peel&stick "foot" (like you'd put on the bottom of electronics or a speaker) to that spot on the cable. Now when you screw the front metal bezel down, the area of that bezel that's supposed to push on those cables, pushes much harder, and the picture is nearly perfect. There remains though, some horizontal lines, at fixed 1" intervals though, that stretch across the display. They are mostly on the right half of the display, and fade away totally by the time they hit the left edge. That's all that's left to get the picture to 100%, but I found no other connections that were bad. If I unplug the right hand side connector from the T-CON board, so that the right hand side of the LCD goes blank, the remaining lines disappear on the left. This tells me that these remaining horizontal lines might be from a bad T-CON board. So I'm replacing that board next. Hopefully, it's 100% after that. I don't have a lot of faith in it though. If it doesn't fix it, it'll make an excellent secondary/bedroom/workout TV lol. The picture is nearly perfect now.

Protonus did replacing the tcon board fix it on the end?

Talnaci Alexandru That's a good idea. The filling of the columns looks capacitive. Doesn't explain why not all columns/colours get vertical lines.

Also explains why the lines phase in slowly when first turned on.

Ian Cole ...but does not explain why every second line is black. I think this is a deliberately fault programmed into the firmware to appear after a certain time of usage so that you buy a new one.

Talnaci Alexandru i think there was tiny SMD capasitors on the pcb along the bottom side of the tv that was together with some resistors... should only take a few minutes to check them out.

+Ian Cole they would fade in if a signal started to slowly rise from a cap charging.

It is entirely possible is not the LCD if so it's the caps which have been fixed but then the tecon board can be the problem but then if it's not that then it's the main board but I've not seen TVs that are built like this and I don't believe after all this time that it's possible for me or most people to be any help but good video I really found it interesting how much could of been wrong with it

+mc349iii I agree.

jaaasgoed Or it could be whatever is doing the rendering for that overlay. As stated, chuck an external test pattern on and some moving video :) (if it is the overlay renderer, well, you could almost just ignore it once you have your settings right)

Darthane I don't think there is anything extra doing the overlay. I assume this is all done internally in the ASIC. But indeed, the same thing applies, give it some signal and see what it does.

ZXRulezzz I guess what I want to say is that maybe column drivers are fine, it's just something wrong with one of horizontal drivers. And that mess of colorful pixels right at the edge of the screen might mean that there's some "horizontal line" clock fell off somewhere (like instead of iterating through the lines, it stuck on first one). But that's just my very specific guess, as not all details are observable in the video.

Watched it all finally and still thinking its just a simple ribbon fix repair/replacement and in the worst it would be a Tcon board replacement if you didn't want to troubleshoot, but still probably the other end of those 2 outgoing ribbons and where they lead though.

Stupid people with more money then sense whom aren't willing to learn anything technical and very handy tend to throw things out.