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?
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.
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.
Hello Dave, I've been watching your channel for about 2 years and you are the reason I'm somewhat interested in electronics. I've got no idea what you say actually means but I feel like I'm learning
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 :)
All the vertical lines, line up exactly with the OSD text, so its looking like it is possibly an issue driving the framebuffer RAM's, I've seen the same style of issue on a much lower tech LED sign display, caused by a decoder with leaky outputs not fully turning off after drawing a pixel, so you ended up with faint trails on the next lines
I love these attempt to repair videos. Like a good detective story it keeps you wondering. I hope you'll continue your investigations and figure this thing out!!
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.
The problem is the LCD panel, this is a very common problem for Samsung TVs. If you disconnect one ribbon cable from the Tconn to the panel the problem might go away (only half the picture will show) and you will know the side that is causing the problem. You can also try some freeze spray on the COFs to see how it reacts.
Dave, from my experience with my TV, it is indeed the T-con board. You realized that the lines are exactly where the letters of the menu are, as if the menu "caused" the problem. If you put a digital image to it, the lines will probably disappear after some minutes and the image will be totally clear until you bring up the menu again or if you try to watch anything analog and the image will probably get even worse then. I'm telling you this, because that was exactly the symptoms of my set. Replacing the T-con solved completely the problem here. According to what I read, the chip the causes the problem is a small squared one with the code AS15-G (at least in my set)
As you have problems on both sides of the split it's probably on the TCON that the problem lies in, as the likelyhood of both sides of the panel TAB bonds going bad at the same time is pretty low. As the problem looks "analog" the scaler board (what you call the main board) is out of the question. A lot of "analog" stuff goes on in the TCON.
Loving these repair/diagnostics videos, as a tight ass dumpster diver these videos only fuel my passion to fix what others would gladly just bin. Thanks Dave(s)
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. :)
The lines appearing only where the characters are looks like a RAM addressing issue to me, like a floating / stuck address line. Since it fades, it's probably floating, so you get an average over time of white and black (text and background) on the whole column. That also explains why the lines have colors close to the text color and the striped pattern (the regular spacing of thin black lines in the red columns)
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.
Love this fault finding problem, yes get the Scope out. This has been fascinating Dave. What a result if you narrow the fault, even if you can't repair it, great experience. The fault does't appear straight away, suggesting a heat fault, maybe it is with the tecon board after all. If the heat fault is in that board, you may need another ASIC.
Maybe interesting: hoe about doing a reverse repair! Introduce an error and look at the effect. Two examples 1) Cut a trace (repairable) on a FR4 based board leading to a flex cable, goal discover what a bad solder joint would introduce. 2) introduce a "stuck at" 1 or 0 error on memory databus.
I would bet on memory problem with some of the cells. I would: 1. Install custom linux image from: www.samygo.tv/ 2. run memcheck on PCU board 3. swap/change memory modules on video board
try your thermal camera on the back, see what warms up, freeze that, as it related to text, how about a video signal input? please try that with no generated text on
EEVblog Dave, this whole stuff can be because of low gate open voltage, there is a dc-dc converter on tcon board somewhere which drives gates, check voltages
I used to heat the boards to the oold CRT TVs on the gas stove. Once I heard cracking, I would drop the boare, component side down, and all of the components would fall out. That is how I would quickly collect boxes of components for fee. Great video. Frank
The problem seems to be more evident with antialiased fonts drawn by osd software lib (you have the issue near the curved lines and not on the horz and vert lines that are instead perfectly row/column aligned), this suggest a timing problem with partially lighted leds... I think you should input some video test signal from a pc software generated image and see if we have changes with full red, full green, full blue, 33% rgb, and so on...
In the event of a suspect main ASIC or memory, feed it a video signal (VGA/HDMI) and try to change the resolution. If you have a memory error the patters will move as the picture is placed differently in RAM.
You didn't put any pressure on the flat flex where it's bonded to the LCD glass, which was the location of this issue on the 2008 Samsung I had. Notice how the lines follow bright areas in the picture at any row. Maybe one of the return lines for the row drivers has lifted, and every pixel in the row slowly floats high if one is high?
I have the same exact problem on a 42" Toshiba from about the same time period. Vertical lines appear in columns containing text, and horizontal "missing" lines are constantly there. It seems to come and go over time; I've been able to use the TV for the past few months without too many problems, but sometimes it just gets in a bad mood or something and the lines cover everything up.
From my experience with the same problem on LG 42" LCD TV (exactly the same manifestations), hotbar connections were the problem. That sticky conductive transparent tape (forgot the name) that bonds flatflex conductors from LCD glass to that upper board was not conducting any more. With blowing hot air from hot air gun, and more importantly putting rubber bars that mechanically pressed the connections, TV was again having good picture. That worked for about the year and then started going bad again. Problem with my TV were old CFL lamps that were getting pretty hot (glowing with more red color), and whole tv screen got hot and those contacts to the flatflex were ruined. After that 1 year of extra life, and 6 years form TV, i just bought new one...
Mmm, if the problem is associated with the OSD characters, what does it do when a full video signal, via HDMI say, is input? Could it be that the OSD generator is cactus?
That would be my guess too. Though cactus isn't the word is use. ;) could also be the part responsible for merging the OSD signal with the video before passing it to the tcon board. It feels nuts even having just a clue how these things work! :D
HI dave, I have the exact same tv and am experiencing the exact same problem as in this video. Did you end up finding the solution for the problem? Would like to find out if there was ever a fix for it, Cheers.
Well, I have a Samung UN40D5500 from 2012 and in past november 2021 went into this same exact problem. I took it to the technical service here it was until now, and being January 2022, service called me yesterday and told me that TV couldn't be fixed since for they the issue is the panel itself and over here is very complicated to get a replace, and very expensive.
it is shockingly impressive the level of futuristic detail and tech applied into the flat screen.... I tend to think that if such effort was applied into... say fixing the environmental problems... like perhaps deforestation.... then there would not be any problem
One Hint for the problem not being linked with a faulty panel might be that all the vertical lines appearing on the display are somehow bonded with the characters displayed! Red collumn -> orange "PC" letters, cluster of lines in the middle -> "Check signal cable." and the one in between -> the ":" in the time (?).
Just to echo another comment or two on here - Mike said floating input, does look that way. Someone else mentioned reflowing processor board and considering OSD text having effect I do agree it's probably the processor board. Something perhaps needs reflow on there.
Problem in the t-with specifically in ntc lack of voltage manage to repair it using a resistance of 270k to 12 vdc and a cable to ntc point this is the max 17122 or 17a ka 1718 any question ask
seems like it could have something to do with a chip heating up, just based on the way it fades in. you could try blowing hot air on different chips while it runs, or look for a particularly hot chip with the thermal camera.
Let's see: 1. The lcd panel cables are good, if the lines would appear instantly after powering the TV on than flex cables would be faulty 2. the panel is not damaged that is a fact, a damaged panel would not have straight lines but bleeding colours 3. power supply is good 4. Image processoring is working because there is video output to the panel 5. The issue is on the video output source So if you put all this together you will se it is related to the T-con, something on the board is damaged because when it is heating up the lines appear slowely (vertical lines) these other horizontal lines are most likely because of some small voltage disruptions on the T-con. I can not say what exactly is damaged on the T-con but you can try and look deeper in to what could be wrong on the T-con's circuit, if the chip is damaged than it is best to buy a whole new board Here is one, I don't know what model do you have de.aliexpress.com/store/product/LN46B650-or-LED-UN46B7000-BOARD-2009FA7M4C4LV0-9/710086_614153320.html?storeId=710086
The Horizontal lines appear to be split between the two sides of the panel(like, even rows on the left and odd rows on the right) and the left horizontal lines "driver" (when the panel is the correct side up) is completely gone (hence no display). But since the vertical "fault" lines appear even on the side with "no" horizontal drive that could be some indicator that the fault originates on the main board that generates the signals for the rest of the components (it skips processing half the rows except where there is an error or "overflow" that produces the vertical lines). Hope this was helpful...
Ten points for keeping it up. I'm sure you guys are closing in on whatever the problem is. Sorry I can't help to diagnose but the character issue seems important. It's odd that stuff is being drawn in placed where the letters never really go. The center bit moves up and down a bit but the 'PC' string pretty much stays in place. Something's not turning off when it should...Good luck guys. Hope you find it.
My bet is framebuffer memory on the main processing board - some rows in memory flip bits, some stay flipped, some decay - this is what happens with videocards. So possibly a memory line doesn't get a refresh signal or something like that... And because it does some postprocessing on the faulty data, it can produce different artifacts depending on when and how the bits flip.
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 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/
I am getting the same issue with water damaged cell phone - it draws lines where are some contrast items. In my case i was thinking that the water+impurities are connecting whole lines together - so if anything in the line light us it affects the other pixels.
This is why TV repair is best left to specialists who have the test equipment. For an electronics engineer wanting to make spare money in their time, it's just not economical enough, but perfectly OK for a blogger on RUclips if it means a large audience.
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. ;-)
may it be the LCD array is not discharging properly (ghosting and downwards fading) or there is a background current added to the pulsed column signals (info) that lit up the pixels along a column.
I have repaired similar TV's and it was an issue with the ribbon cables coming off the lcd not making good contact in the connector. I would use packaging tape to make the cable a bit thicker for the fix.
I believe it's to do with the LCD itself I've seen this before where the LCD broke and caused lines and dead pixels so a replacement of the LCD would be required
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
I am not very expert in this but could the culprit be the chip that is producing menu graphics? Because we are seeing lines only on menu characters so this is related to menu graphics chip
This is an internal panel short, you can narrow down which signal lines the shorts on by putting capton tape over some of the pins on the ribbon end, on one of the 2 ribbons going to the panel buffer boards
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
Like other people suggested, hook up a video source and see what it does. It fades in and out in a couple of seconds with a static image, maybe a moving image won't be a problem?
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.
***** this is how you could isolate the error and see if it is the processing board or not. Once I was fixing a TV when I thought about using the s-video and it worked! Also one HDMI could give a different result to another. You never know till you try
+Osmosis because that would be a problem of the processing board. because it is generated by part of it, maybe the same part generates the test image, but the HDMI part is isolated, because also HDMI does require a special chip doesn't it
Anas Malas It looks like an analog problem yes, but by the time you get to the OSD generator (which may be causing the issue) the PC signal would be digitized anyways. The first step in the process would be to convert any analog inputs to digital using an ADC. Since it's displaying the PC label that means it hasn't detected a valid signal anyways, so it's ignoring any analog inputs. If it were an analog issue (which is likely is given the failure mode) it would be on the TCON board or the panel. The LVDS connection to the TCON board is 100% digital.
Osmosis It doesn't just follow ASCII characters. You can see at 22:23 that the vertical lines go through some non-ASCII symbols. It's possible that those are encoded in an extended ASCII table, but it seems more likely that the lines just go through anything bright on the screen.
Well, looks like I was wrong about the TAB's being the issue. It looks very similar to a tab issue, but upon your further investigation, it became obvious that was not it. Ah well, those panels are a marvel to see anyway, so wasn't a complete waste of time.
Did you guys ever throw a new T-con board in there and see if it worked? Did you fix it at all somehow? I've got a Toshiba 42" TV I'm trying to fix that is doing the exact same thing.
It fades in over a short time. Is there maybe some dynamic contrast system running on this TV, is there a light sensor on the TV? It's definitely an analog issue, not digital.
Deathlok67 Just to add to this, it may not be a fault in the video processor, it's just over-driving the signal due to some erroneous analog feedback (eg. room light level or similar).
The fix! Try to measure all the capacitors to see if they are bad. The vertical filtering capacitor is the problem! Try the fix. I got this answer from my dad!
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.
Hi i have an medion LED tv with this exact T-con board. the problem I am having is that I dont have any picture, but the sound and backlighting work. What is the best way to troubleshoot this board?
EEVblog Check those Sam Young filter caps on the power supply board using your ESR meter! I don't see that you did that in either video. I know you have no reason to think they're bad based on ripple and visual diagnosis. BUT - I have a very similar vintage Samsung LCD TV (2009, 55", high end) I'm working on, that also has multiple Sam Young filter caps on a very similar board. One of them was visibly bulged, but even the ones that weren't in the same value (25V 1000uF) had questionable/high ESR values. The TV I'm working on has the same exact symptoms. I'm waiting for the replacement caps to arrive, but given the nature of the failure (it worsened with time according to the owner, used to go away on it's own, and it's temperature related) etc, and the fact that one had visibly failed - I'm confident that this is what's wrong.
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.
Maybe each driver board drives an interlaced half of screen lines, like one board drives odd lines, and another drives even ones. Maybe one of the boards stopped driving horizontal lines and they are left floating. And maybe the signal that drives "bright" pixels leaks over to "dead" lines on the screen... I have a laptop from early 90's that has its monochrome LCD messed up kinda like that. But what I know about it for sure is that it really has some rows disconnected from the driver right on the glass. Disconnected rows look really dark with vertical ghosting stripes from nearby characters. Just throwing my 2 cents in here :)
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.
got this issue on my tv and just uploaded a video, with a desktop background (a still image with lots of different text /game icons the lines literally cover the screen after being on for a minute or so
I'm probably way off with this, but I'm thinking that if each pixel has a triple (RGB) x,y control, the vertical lines seem to follow any high-contrast element of significant height (the dashes in the clock display didn't seem to contribute), and the line color seems to be determined by the dominant color of the contrasting element, then there must be a communication issue in the x,y controller, whatever that may be. Blue is the dominant contributor to the "white" (it's not pure white/all-on white) text. Red is the dominant contributor to the orange text ("PC") It seems like the vertical controller is taking cues from the horizontal controller. Knowing absolutely nothing about how this screen is engineered, I find myself asking: 1) Are the x and y controllers physically separate drivers? 2) Does either the x or y have "priority" to the system? 3) Do they communicate, and/or does one vary itself compared to the other? (Contrast management? Blacks enhancement?) 4) Are they SUPPOSED to communicate? Is there a chance that information from one is "bleeding over" into the other? 5) Is this a heat-related, actively-bridged problem? How long does it take for a particular die and/or circuit to reach a temperature or charge that would, say, cause a tin whisker or similar anomaly to expand and bridge a gap, which it then holds based on heat or charge until the unit is powered down and the anomaly is pulled away?
It's not the processor board. The text in the OSD just happens to be the only full brightness items on the screen shown so far since he hasn't shown us any other video signals but it will look the same with any full brightness areas of image on the screen.
MrCube17 Not sure at all, but the proc. board is sending to the tcon board the whole screen pixel data at 60hz, the signals going on this strip should be insane fast since just a few lines to make the whole panel. Would be interesting to probe there to see the actual freq and rise time of this lines, almost RF stuff to me.
Dear EEV. Ive got a samsung H series. Its 2 years old. Just this month it starts to get large pUrple hazy spots. Any Ideas on what it is and how to fix it? Kind regards
You can buy a working T-Con board on E-Bay for about or less than 60.00....From a HDTV with a broken screen they sell all the good parts from it....power board and main boards....inverter...
If you look closely, lines do align with "P C" (the red ones) with check cable, and with time dots. Looks like some sort of filter accumulates values or something, definitely something with the scaler/frame buffer or something like that.
Is there edge mount LEDs in that? How about tearing them down. I have some that seem to be 6 volts each but can not find any information on them to drive them. How about a video on how to reuse them for lighting? Sony and Samsung seem to use edge lighting and LG back lighting. Also a friend of repairs TVs and says the streaks are caused by the panel itself.
So, what happens if you put a video signal on it and place it in a mode so no tv generated text is displayed? Also, it is strange that when powered up, the lines ramps up in brightness.
Since in fades in, I don't think this is on the digital side. More like a analog thing between the driver chips and the panel. Could also be wrong supply voltages to the panel.
Hi Friend, first of all congratulations for the video. I wanted to ask you for help: I have a problem with my Samsung LE40B530P7WX TV because it has horizontal stripes. I did several tests but nothing. Could you tell me which are the PINs that I have to block with the tape, I can not understand which is the trace of the signal (VCOM, CLKN, CLKP, CPV, STV, VGM ....) that is causing the problem. A thousand thanks.
Wait, my monitor is the same with the lines and doesn't work. Did we come to any conclusions about the failure? Just noticed this is part 2, I'll look for part 3.
Did this TV ever get fixed?
Surely it's 1920xRGB=5760 columns?
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?
The fade-in and shadowing says "floating input somewhere" to me
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.
Hello Dave, I've been watching your channel for about 2 years and you are the reason I'm somewhat interested in electronics. I've got no idea what you say actually means but I feel like I'm learning
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 :)
All the vertical lines, line up exactly with the OSD text, so its looking like it is possibly an issue driving the framebuffer RAM's, I've seen the same style of issue on a much lower tech LED sign display, caused by a decoder with leaky outputs not fully turning off after drawing a pixel, so you ended up with faint trails on the next lines
can you explain for me a little more please ?
Dwwd
Dwwdd
I love these attempt to repair videos. Like a good detective story it keeps you wondering. I hope you'll continue your investigations and figure this thing out!!
hook up a video signal to it and watch it clear up after the menu text dissappear.
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?
The problem is the LCD panel, this is a very common problem for Samsung TVs. If you disconnect one ribbon cable from the Tconn to the panel the problem might go away (only half the picture will show) and you will know the side that is causing the problem. You can also try some freeze spray on the COFs to see how it reacts.
Dave, from my experience with my TV, it is indeed the T-con board. You realized that the lines are exactly where the letters of the menu are, as if the menu "caused" the problem. If you put a digital image to it, the lines will probably disappear after some minutes and the image will be totally clear until you bring up the menu again or if you try to watch anything analog and the image will probably get even worse then. I'm telling you this, because that was exactly the symptoms of my set. Replacing the T-con solved completely the problem here.
According to what I read, the chip the causes the problem is a small squared one with the code AS15-G (at least in my set)
Did he trickle some flux under the BGA chips ?
Have they tried actually feeding a signal in over HDMI or VGA?
If you look, the lines only appear where the text is, I'm guessing T-con for sure.
As you have problems on both sides of the split it's probably on the TCON that the problem lies in, as the likelyhood of both sides of the panel TAB bonds going bad at the same time is pretty low. As the problem looks "analog" the scaler board (what you call the main board) is out of the question. A lot of "analog" stuff goes on in the TCON.
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.
Loving these repair/diagnostics videos, as a tight ass dumpster diver these videos only fuel my passion to fix what others would gladly just bin.
Thanks Dave(s)
Lower the brightness level and color intensity and when the menu text dissappear it goes to normal viewing
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. :)
The lines appearing only where the characters are looks like a RAM addressing issue to me, like a floating / stuck address line. Since it fades, it's probably floating, so you get an average over time of white and black (text and background) on the whole column. That also explains why the lines have colors close to the text color and the striped pattern (the regular spacing of thin black lines in the red columns)
What’s the fix
The TV manufacturers won't like it if you find a bypass for their "Built in obsolescence" lol..
A very interesting project though. 👍🏼
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.
Love this fault finding problem, yes get the Scope out.
This has been fascinating Dave.
What a result if you narrow the fault, even if you can't repair it, great experience.
The fault does't appear straight away, suggesting a heat fault, maybe it is with the tecon board after all.
If the heat fault is in that board, you may need another ASIC.
Maybe interesting: hoe about doing a reverse repair! Introduce an error and look at the effect. Two examples 1) Cut a trace (repairable) on a FR4 based board leading to a flex cable, goal discover what a bad solder joint would introduce. 2) introduce a "stuck at" 1 or 0 error on memory databus.
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 :)
I would bet on memory problem with some of the cells. I would:
1. Install custom linux image from: www.samygo.tv/
2. run memcheck on PCU board
3. swap/change memory modules on video board
try your thermal camera on the back, see what warms up, freeze that, as it related to text, how about a video signal input? please try that with no generated text on
EEVblog Dave, this whole stuff can be because of low gate open voltage, there is a dc-dc converter on tcon board somewhere which drives gates, check voltages
I used to heat the boards to the oold CRT TVs on the gas stove. Once I heard cracking, I would drop the boare, component side down, and all of the components would fall out. That is how I would quickly collect boxes of components for fee. Great video.
Frank
It would be great if you had a service manual showing testing points. A real time saver.
The problem seems to be more evident with antialiased fonts drawn by osd software lib (you have the issue near the curved lines and not on the horz and vert lines that are instead perfectly row/column aligned), this suggest a timing problem with partially lighted leds...
I think you should input some video test signal from a pc software generated image and see if we have changes with full red, full green, full blue, 33% rgb, and so on...
In the event of a suspect main ASIC or memory, feed it a video signal (VGA/HDMI) and try to change the resolution. If you have a memory error the patters will move as the picture is placed differently in RAM.
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.
You didn't put any pressure on the flat flex where it's bonded to the LCD glass, which was the location of this issue on the 2008 Samsung I had. Notice how the lines follow bright areas in the picture at any row. Maybe one of the return lines for the row drivers has lifted, and every pixel in the row slowly floats high if one is high?
I have the same exact problem on a 42" Toshiba from about the same time period. Vertical lines appear in columns containing text, and horizontal "missing" lines are constantly there. It seems to come and go over time; I've been able to use the TV for the past few months without too many problems, but sometimes it just gets in a bad mood or something and the lines cover everything up.
From my experience with the same problem on LG 42" LCD TV (exactly the same manifestations), hotbar connections were the problem. That sticky conductive transparent tape (forgot the name) that bonds flatflex conductors from LCD glass to that upper board was not conducting any more. With blowing hot air from hot air gun, and more importantly putting rubber bars that mechanically pressed the connections, TV was again having good picture. That worked for about the year and then started going bad again. Problem with my TV were old CFL lamps that were getting pretty hot (glowing with more red color), and whole tv screen got hot and those contacts to the flatflex were ruined. After that 1 year of extra life, and 6 years form TV, i just bought new one...
Mmm, if the problem is associated with the OSD characters, what does it do when a full video signal, via HDMI say, is input? Could it be that the OSD generator is cactus?
That would be my guess too. Though cactus isn't the word is use. ;)
could also be the part responsible for merging the OSD signal with the video before passing it to the tcon board.
It feels nuts even having just a clue how these things work! :D
Jim Groth cacti are always problems...
Prehistoricman Good point.
Jim Groth Another cacti joke I like it.
Michael Norman Completely unintentional pun! :D
Looks like a chip on glass warming up problem to me, try your hot air iron round the outer edge of the screen while its turned on.
HI dave, I have the exact same tv and am experiencing the exact same problem as in this video. Did you end up finding the solution for the problem? Would like to find out if there was ever a fix for it, Cheers.
Well, I have a Samung UN40D5500 from 2012 and in past november 2021 went into this same exact problem. I took it to the technical service here it was until now, and being January 2022, service called me yesterday and told me that TV couldn't be fixed since for they the issue is the panel itself and over here is very complicated to get a replace, and very expensive.
it is shockingly impressive the level of futuristic detail and tech applied into the flat screen.... I tend to think that if such effort was applied into... say fixing the environmental problems... like perhaps deforestation.... then there would not be any problem
You have problem on glass lsd panel, bad connection or short, i have same problem with Sony.
You have tried it with an external source, it's not just a problem with the OSD?
One Hint for the problem not being linked with a faulty panel might be that all the vertical lines appearing on the display are somehow bonded with the characters displayed! Red collumn -> orange "PC" letters, cluster of lines in the middle -> "Check signal cable." and the one in between -> the ":" in the time (?).
What happens when you plug an HDMI or something in and there is no HUD on the screen at all?
Just to echo another comment or two on here - Mike said floating input, does look that way. Someone else mentioned reflowing processor board and considering OSD text having effect I do agree it's probably the processor board. Something perhaps needs reflow on there.
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?
Problem in the t-with specifically in ntc lack of voltage manage to repair it using a resistance of 270k to 12 vdc and a cable to ntc point this is the max 17122 or 17a ka 1718 any question ask
Can you explain a bit more?
seems like it could have something to do with a chip heating up, just based on the way it fades in. you could try blowing hot air on different chips while it runs, or look for a particularly hot chip with the thermal camera.
Let's see:
1. The lcd panel cables are good, if the lines would appear instantly after powering the TV on than flex cables would be faulty
2. the panel is not damaged that is a fact, a damaged panel would not have straight lines but bleeding colours
3. power supply is good
4. Image processoring is working because there is video output to the panel
5. The issue is on the video output source
So if you put all this together you will se it is related to the T-con, something on the board is damaged because when it is heating up the lines appear slowely (vertical lines) these other horizontal lines are most likely because of some small voltage disruptions on the T-con. I can not say what exactly is damaged on the T-con but you can try and look deeper in to what could be wrong on the T-con's circuit, if the chip is damaged than it is best to buy a whole new board
Here is one, I don't know what model do you have de.aliexpress.com/store/product/LN46B650-or-LED-UN46B7000-BOARD-2009FA7M4C4LV0-9/710086_614153320.html?storeId=710086
The Horizontal lines appear to be split between the two sides of the panel(like, even rows on the left and odd rows on the right) and the left horizontal lines "driver" (when the panel is the correct side up) is completely gone (hence no display). But since the vertical "fault" lines appear even on the side with "no" horizontal drive that could be some indicator that the fault originates on the main board that generates the signals for the rest of the components (it skips processing half the rows except where there is an error or "overflow" that produces the vertical lines). Hope this was helpful...
If the lines only appear when there's text on screen, then there ought to be no lines when it's showing video only?
Have you tried connecting an input via HDMI yet? Ignoring the built in menus & overlays.
Ten points for keeping it up. I'm sure you guys are closing in on whatever the problem is. Sorry I can't help to diagnose but the character issue seems important. It's odd that stuff is being drawn in placed where the letters never really go. The center bit moves up and down a bit but the 'PC' string pretty much stays in place. Something's not turning off when it should...Good luck guys. Hope you find it.
My bet is framebuffer memory on the main processing board - some rows in memory flip bits, some stay flipped, some decay - this is what happens with videocards. So possibly a memory line doesn't get a refresh signal or something like that... And because it does some postprocessing on the faulty data, it can produce different artifacts depending on when and how the bits flip.
One of the design engineers from Samsung is watching this doing a face palm. Come on tell us which £0.01 component is faulty :-)
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/
Why have you not put in a video signal? The defect could be in the OSD video signal path (the built in test image could be the same path also).
+Doom2pro Are you sure?
I am getting the same issue with water damaged cell phone - it draws lines where are some contrast items. In my case i was thinking that the water+impurities are connecting whole lines together - so if anything in the line light us it affects the other pixels.
The vertical issue was all over the test image as well? Perhaps not specific to ASCII characters rather to intensity?
hey . have you tried just plugging an input in and see if it works ?? the lines don't se to be affecting the graphics,just the ASCII .
This is why TV repair is best left to specialists who have the test equipment. For an electronics engineer wanting to make spare money in their time, it's just not economical enough, but perfectly OK for a blogger on RUclips if it means a large audience.
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. ;-)
may it be the LCD array is not discharging properly (ghosting and downwards fading) or
there is a background current added to the pulsed column signals (info) that lit up the pixels along a column.
I have repaired similar TV's and it was an issue with the ribbon cables coming off the lcd not making good contact in the connector. I would use packaging tape to make the cable a bit thicker for the fix.
So whats the problem? Did you fixed it? Is the screen itself is the problem??? needs replacement? tnx
I believe it's to do with the LCD itself I've seen this before where the LCD broke and caused lines and dead pixels so a replacement of the LCD would be required
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
Silly question but could it be a corruption in the software? Could doing a factory reset via the menu/service menu help?
I am not very expert in this but could the culprit be the chip that is producing menu graphics? Because we are seeing lines only on menu characters so this is related to menu graphics chip
Dave! Check Vgh and Vgl voltage. please check the voltage with a oscilloscope.
This is an internal panel short, you can narrow down which signal lines the shorts on by putting capton tape over some of the pins on the ribbon end, on one of the 2 ribbons going to the panel buffer boards
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
Like other people suggested, hook up a video source and see what it does. It fades in and out in a couple of seconds with a static image, maybe a moving image won't be a problem?
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.
On the T-CON board, what happens when you spray D22 & D23 with a can of cold spray?
I think it is an analog problem. as it is now in "pc" mode, I think in digital mode such as HDMI it would work
Anas Malas doesn't explain why it follows ascii characters.
***** this is how you could isolate the error and see if it is the processing board or not. Once I was fixing a TV when I thought about using the s-video and it worked!
Also one HDMI could give a different result to another. You never know till you try
+Osmosis because that would be a problem of the processing board. because it is generated by part of it, maybe the same part generates the test image, but the HDMI part is isolated, because also HDMI does require a special chip doesn't it
Anas Malas It looks like an analog problem yes, but by the time you get to the OSD generator (which may be causing the issue) the PC signal would be digitized anyways. The first step in the process would be to convert any analog inputs to digital using an ADC. Since it's displaying the PC label that means it hasn't detected a valid signal anyways, so it's ignoring any analog inputs. If it were an analog issue (which is likely is given the failure mode) it would be on the TCON board or the panel. The LVDS connection to the TCON board is 100% digital.
Osmosis It doesn't just follow ASCII characters. You can see at 22:23 that the vertical lines go through some non-ASCII symbols. It's possible that those are encoded in an extended ASCII table, but it seems more likely that the lines just go through anything bright on the screen.
Well, looks like I was wrong about the TAB's being the issue. It looks very similar to a tab issue, but upon your further investigation, it became obvious that was not it. Ah well, those panels are a marvel to see anyway, so wasn't a complete waste of time.
are the pixel colors not reseting?. itll change color, but only once?
If you tv has not got a hdmi out can you take the back off and add another board in that will give you that function
EEVblog 3d print a new post and remove the bits of the old one and then glue in the 3d printed one with epoxy glue
Did you guys ever throw a new T-con board in there and see if it worked? Did you fix it at all somehow? I've got a Toshiba 42" TV I'm trying to fix that is doing the exact same thing.
It fades in over a short time. Is there maybe some dynamic contrast system running on this TV, is there a light sensor on the TV? It's definitely an analog issue, not digital.
Deathlok67 Just to add to this, it may not be a fault in the video processor, it's just over-driving the signal due to some erroneous analog feedback (eg. room light level or similar).
The fix! Try to measure all the capacitors to see if they are bad.
The vertical filtering capacitor is the problem! Try the fix. I got this answer from my dad!
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.
Hi i have an medion LED tv with this exact T-con board. the problem I am having is that I dont have any picture, but the sound and backlighting work. What is the best way to troubleshoot this board?
How does it look with actual video being sent to it instead of showing a 'no signal' and menu items?
I wonder where it is now. scraped?
EEVblog Check those Sam Young filter caps on the power supply board using your ESR meter! I don't see that you did that in either video. I know you have no reason to think they're bad based on ripple and visual diagnosis. BUT - I have a very similar vintage Samsung LCD TV (2009, 55", high end) I'm working on, that also has multiple Sam Young filter caps on a very similar board. One of them was visibly bulged, but even the ones that weren't in the same value (25V 1000uF) had questionable/high ESR values.
The TV I'm working on has the same exact symptoms.
I'm waiting for the replacement caps to arrive, but given the nature of the failure (it worsened with time according to the owner, used to go away on it's own, and it's temperature related) etc, and the fact that one had visibly failed - I'm confident that this is what's wrong.
+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?
Problems like this are so interesting. Keen for Part 3!
Maybe each driver board drives an interlaced half of screen lines, like one board drives odd lines, and another drives even ones. Maybe one of the boards stopped driving horizontal lines and they are left floating.
And maybe the signal that drives "bright" pixels leaks over to "dead" lines on the screen...
I have a laptop from early 90's that has its monochrome LCD messed up kinda like that. But what I know about it for sure is that it really has some rows disconnected from the driver right on the glass. Disconnected rows look really dark with vertical ghosting stripes from nearby characters.
Just throwing my 2 cents in here :)
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.
Should the 2 boxes be static instead of shifting up and down randomly?
No
The way the fault fades in has to be a vital clue. Also - why not put in your own signal?
can anyone tell me please from where i can get my desired screen panel online? My TV model is LG 42LB5820.. thank you....
i love it when we are in like flynn!
Did you ever fix it??
So it seems to only follow the Text. Try displaying some text through the HDMI port to see if its the firmware the doing it to overlaid messages.
May i know what is the solution for this? I just got same symptoms
got this issue on my tv and just uploaded a video, with a desktop background (a still image with lots of different text /game icons the lines literally cover the screen after being on for a minute or so
I'm probably way off with this, but I'm thinking that if each pixel has a triple (RGB) x,y control, the vertical lines seem to follow any high-contrast element of significant height (the dashes in the clock display didn't seem to contribute), and the line color seems to be determined by the dominant color of the contrasting element, then there must be a communication issue in the x,y controller, whatever that may be.
Blue is the dominant contributor to the "white" (it's not pure white/all-on white) text.
Red is the dominant contributor to the orange text ("PC")
It seems like the vertical controller is taking cues from the horizontal controller. Knowing absolutely nothing about how this screen is engineered, I find myself asking:
1) Are the x and y controllers physically separate drivers?
2) Does either the x or y have "priority" to the system?
3) Do they communicate, and/or does one vary itself compared to the other? (Contrast management? Blacks enhancement?)
4) Are they SUPPOSED to communicate? Is there a chance that information from one is "bleeding over" into the other?
5) Is this a heat-related, actively-bridged problem? How long does it take for a particular die and/or circuit to reach a temperature or charge that would, say, cause a tin whisker or similar anomaly to expand and bridge a gap, which it then holds based on heat or charge until the unit is powered down and the anomaly is pulled away?
I would have re-flowed the processor board. The OSD and test image seem to be the issue and surely they come from the processor board.
Darren Jacobson Yeah, next step, just for kicks.
+EEVblog Is there maybe a separate part that handles the OSD?
It's not the processor board. The text in the OSD just happens to be the only full brightness items on the screen shown so far since he hasn't shown us any other video signals but it will look the same with any full brightness areas of image on the screen.
What about the lines next to the : ?
Does the length matching of the conductors in the LCD flex make significant difference to timings?
MrCube17 Not sure at all, but the proc. board is sending to the tcon board the whole screen pixel data at 60hz, the signals going on this strip should be insane fast since just a few lines to make the whole panel. Would be interesting to probe there to see the actual freq and rise time of this lines, almost RF stuff to me.
+MrCube17 Why? Do you think one of the flex cables grew longer?
The Kaiser The ribon has a shape to avoid twisting, it make a turn
38911bytefree Ah you just want to see the video signal on the oscilloscope to see how it being send. Good idea, that's interesting.
Dear EEV. Ive got a samsung H series. Its 2 years old. Just this month it starts to get large pUrple hazy spots. Any Ideas on what it is and how to fix it?
Kind regards
You can buy a working T-Con board on E-Bay for about or less than 60.00....From a HDTV with a broken screen they sell all the good parts from it....power board and main boards....inverter...
If you look closely, lines do align with "P C" (the red ones) with check cable, and with time dots. Looks like some sort of filter accumulates values or something, definitely something with the scaler/frame buffer or something like that.
Is there edge mount LEDs in that? How about tearing them down. I have some that seem to be 6 volts each but can not find any information on them to drive them. How about a video on how to reuse them for lighting? Sony and Samsung seem to use edge lighting and LG back lighting. Also a friend of repairs TVs and says the streaks are caused by the panel itself.
in the old TV somethings like chroma ?? voltage drop on the rgb ?
So, what happens if you put a video signal on it and place it in a mode so no tv generated text is displayed? Also, it is strange that when powered up, the lines ramps up in brightness.
To date I've not got what is the cause of the problem and what was the fix
Check out the way they matched the length of the traces in that cable. The railroad could do this on the inside track on curves.
Since in fades in, I don't think this is on the digital side. More like a analog thing between the driver chips and the panel. Could also be wrong supply voltages to the panel.
I just ran into this same problem. There is a bad connection somewhere on the digital input board.
Hi Friend, first of all congratulations for the video. I wanted to ask you for help: I have a problem with my Samsung LE40B530P7WX TV because it has horizontal stripes. I did several tests but nothing. Could you tell me which are the PINs that I have to block with the tape, I can not understand which is the trace of the signal (VCOM, CLKN, CLKP, CPV, STV, VGM ....) that is causing the problem. A thousand thanks.
EEVblog I had a TV once that did the same thing, the lines followed certain colors on the screen.
Wait, my monitor is the same with the lines and doesn't work. Did we come to any conclusions about the failure? Just noticed this is part 2, I'll look for part 3.