EEVblog #725 - LG Plasma TV Teardown

[EEVblog]

Dave takes a peek inside the 50" LG Plasma TV found in the dumpster.
The Dumpster Dive video was on the EEVblog2 channel:

[mux]

I used to love these screens; the university once bought a whole bunch of them as display monitors, most of them died within one or two years and they would dump them en masse. They had incredibly many high quality and useful components in them. Those were also LG screens that used about 400W in normal operation!

Unfortunately, newer plasmas are considerably less valuable. Lots less power electronics and the electronics on there are less usable for parts. Screens still die after a laughably short amount of time and even though BOL image quality is undisputably great, after a while they all ghost and become very dim.

[mikeselectricstuff]

I think that first "fuse" was a ferrite bead.

Would be interesting to see what's under the heatsinks on the HV driver boards.

[bktemp]

Is it only the light beeing reflected or do those caps look bulged? There seems to be even some black stuff leaking at the top of each cap or are the caps deliberately beeing marked?

[Sionyn]

i checked out the smawha caps website their slogan is the challenge never ends... except for maybe making decent capacitors ?   

[T3sl4co1l]

Not sure if that's black stuff oozing out, maybe more like the shadow inside the split.  They definitely look busted though.  Probable cause!

Tim

[woox2k]

Is it only the light beeing reflected or do those caps look bulged? There seems to be even some black stuff leaking at the top of each cap or are the caps deliberately beeing marked?

Those are definitely bad caps even though the black stuff is just a marker. (quite common on those caps, probably marked after testing) I was screaming at my monitor when Dave was talking about the caps in the high-voltage supply and didn't notice the horde of bad caps in the logic power supply.

[Rasz]

Is it only the light beeing reflected or do those caps look bulged? There seems to be even some black stuff leaking at the top of each cap or are the caps deliberately beeing marked?

Those are definitely bad caps even though the black stuff is just a marker. (quite common on those caps, probably marked after testing) I was screaming at my monitor when Dave was talking about the caps in the high-voltage supply and didn't notice the horde of bad caps in the logic power supply.

Dave subscribes to 'lets talk about it' school of repair videos.

[Fungus]

You mean the ones at 12:25 onward in the video?

How could Dave have missed those...? 

[woox2k]

About the worth of repairing something. I can understand that the usage value is quite low on plasma screens these days but it's always worth to look into faults more closely and try to fix it. It's a EE channel afterall and repairing even the simplest things can teach a lot to people watching those videos. Like figuring out that bad caps can create weird lines and flicker on the screen like it is the case here probably. Even if the device is beyond economical repair Dave should look into it until he knows the source of the problem so other people might know what to look for in similar cases in the future.
Anyway, +1 to the videos where Dave actually tries to repair something.

It was just my opinion, i will not stop watching the videos either way. 

[ludek]

I think that Dave don't want to waste time, replacing caps... Just teardown. There's also only two film shots showing bad caps really clearly. And the other thing is it's weight - 50 kg...

Well, if I'd found a big plasma while dumpster diving - I could spend some time repairing this.


nice vid Dave btw.

[SeanB]

5V, 3V3 and 12V rails off the LV section are all dead. There are about a dozen caps to change to get a nice 50 inch room heater. I went near one in a shop, and could both feel the heat radiating off the screen and feel my fillings buzzing from the RF energy.

[max666]

... I was screaming at my monitor when Dave was talking about the caps in the high-voltage supply and didn't notice the horde of bad caps in the logic power supply.

I think Dave does it on purpose ... checking if we pay attention 

[Refrigerator]

Wait, you say these things fill the dumpsters ? where are those dumpsters ? i could definetly use some parts from those. 
By the way i noticed you were whistling a different melody than usual. 

[Spyke]

PDP's there would run at 50hertz vs 60 in north america/japan, etc. I don't know about anyone else but a 50hertz flicker is extremely irritating for me personally, its so bad that I could never watch TV over in Europe or the UK when tube tv's were the norm because of this. Thankfully LCD backlighting has eliminated that issue entirely.

I completely understand Dave's lack of motivation to repair this. He surely saw those caps but is playing a fast one on the rest of us to see if we noticed. Using a power hungry PDP in this day and age would be taking a huge step backwards, though one can argue about that if they still own a Kuro Elite, etc.

[DanielS]

5V, 3V3 and 12V rails off the LV section are all dead. There are about a dozen caps to change to get a nice 50 inch room heater.

The low-voltage caps powering the logic boards may explain the occasional video glitches but the flickering would have to come from the display panel circuitry and the HV caps appeared to be fine. I would have liked to see oscilloscope measurements of each rail to see how clean (or dirty) they were, see if any obvious suspect would have come up this way.

[herrmann]

I was screaming at my monitor when Dave was talking about the caps in the high-voltage supply and didn't notice the horde of bad caps in the logic power supply.

Me too, especially because you can recognize them immedeatly even from far look after the removing of the backplane. As a Professional he is, he should have mentioned them at least, unaware of the intention to repair it or not.

Just my 2 Cent

Greetings from Germany 

[tom66]

The flicker is because it's a really cheap early LG plasma panel, FHD at that. So it's refreshing the panel at 360/480Hz per sustain or 6/8 subfields per main field. Pick up a late model 2013 Panasonic/Samsung/LG plasma and you won't get any flicker. Or a 9G Kuro. Flicker free.

Plasmas tend to last longer, mainly because the power electronics on an LCD are concentrated on the panel itself and these are thin ICs which dissipate watts a piece mounted right next to hot LED backlight bars.  Yeah, the power electronics can fail but so can the power electronics in LED- and CCFL-backlit LCD TVs. I've not noticed the power electronics being much less reliable but if something's gonna die on a plasma it'll be that.  At least you can repair the electronics if they do fail - you can't repair the LCD source drivers and it's a pain in the arse to replace the LEDs in backlit or edgelit screens, which seem to be failing quite a lot in Samsung and LG TVs.

Dave if you'd like to have fun with giving this panel a fitting funeral as it's already dead, take off the top and bottom long heatsinks and play a movie on the screen. After about 10 minutes the panel will slowly start frying itself and will fill itself with flickering colour lines and digital glitches. The TCP drivers dissipate a LOT of heat in the old panels (that thin daggy wiring is easily carrying 750mA@60V for the top & bottom, image dependent!) so they don't last long. The power consumption on Va is dependent on the image complexity - number of transitions per frame in vertical axis - rather than actual brightness. On a solid colour it can be under 20mA oddly enough. Makes for a difficult power supply design, must handle current swing from 20mA to 1.5A in one subfield (1/480Hz older panels, 1/1200Hz newer panels.) Hence the large amount of capacitance spread across the supply for Va to help with transient response.

BTW, it's incorrect to say Vs=Horizontal and Va=Vertical. The Vs is the SUSTAIN voltage (that's why it's called Vs) and powers the sustain drivers. Ultimately Vs actually makes the panel emit light. The Va is the ADDRESS voltage. That's what writes the data to panel itself, for display during a sustain field. The 570W figure is a purely theoretical figure that they have to put on for UL, which includes if the control board ISM mode is set to commercial display (ultra high bright.) Consumer 50" panels peak out at 400W from PSU  including Va and 450W from the mains. once you add in main board, audio, etc you're up to about 470-500W for a 2008 panel. 2013 panels from Panasonic got it below 200W peak and 125W average which is a pretty big leap, obviously still quite a lot but cool enough to run without fans.

And you'd have to pry my Kuro from my cold dead hands. I can't stand watching LCDs for anything with any dark content. Sure, they're better on brightness and power, but yuck. I justify the extra power usage as my dishwasher and fridge use more. Plasma gets <10hr/week use now.  It's reserved for movies and nature documentaries.

[Grapsus]

I once repaired a 50" LG plasma TV, it was an older model and had spurious horizontal lines. I was lucky to find a full service manual, it helped to narrow the problem down to Z sustain board (or maybe it was Y sustain). I got a replacement board for like $70.

I don't think those boards are repairable on component level. Since it's mainly a sort of a huge hybrid that is under those huge flat black heatsinks that contains many bare-die high voltage transistors bonded together on an aluminum plate. Unless of course you have crazy skills like Mike 

Sadly I found no service manual for 50PY3DF, but even with the manual you would have to find a 7 year old replacement board. So I totally agree that this TV is only good for salvaging parts.

About LG not using top brand caps, seeing how many they are and how big, I wonder how much it would cost to get equivalent Nippon Chemicon caps, probably more than the retail price of this TV...

[JoeN]

I have a Panasonic Viera TH-42PZ85U 42-Inch plasma I got in June 2008 and it still works fine, but maybe I don't watch enough TV to cause reliability issues.   

I think it's still better picture quality than almost all LCDs these days.  70.5 pounds, but it was lighter than the 35" CRT TV it replaced.

Apparently I paid $1300 for it.  TVs are cheaper now, but I don't think the quality is any better on 1080p models.

I'll replace it when I have to and probably not before.

[RetroGameModz]

Just as bktemp clearly pointed out in reply #4, and as other posters have also pointed out after that, those electrolytic capacitors on the power supply board have definitely gone bad and need to be replaced. I think that it's very likely that these caps are what's causing the problem, since insufficient smoothing of the supply voltages for the main board might affect the operation of that board. At least one of the supply voltages for the main board probably has a lot of ripple on it, which should be easy to see on a scope.
It becomes even more obvious when looking at the symptom at 18:49 in the video. A problem with either the Y sustain, Y buffer, Z sustain or X address board can cause a number of problems, but the symptoms usually then look completely different than what we saw here. Vertical or horizontal stationary or flickering lines or bars, horizontal lines flickering across the whole screen, dead portions of the image etc etc... The symptoms from those boards failing can be many, but what I saw in this video looked more like something being introduced already in the main board, which of course is due to the bad output caps for the main board in the power supply.
Looking at the statistics over common faults on plasma TVs (and CRT TVs too for that matter), the power supply output capacitors for the different power rails are the no 1 common issue when these devices fail. This is not strange considering these capacitors are operating in a very warm environment. The capacitors in this particular TV (as in many other plasma TVs) are sitting in the middle of two fat heat sinks as can easily be seen in the picture from reply #4, and warm ambient temperature does not go hand in hand with long operating life when it comes to e-caps, as we all know.

I really cannot understand how Dave could miss these bad capacitors. I noticed them pretty much instantly when the power supply shot started at around 5:52 into the video, and I was just waiting for him to spot them and mention something about them. Starting from 12:17, we are getting a close up of those caps and Dave is even waving around with his spudger over them, yet still misses to see them...? 
Like someone else mentioned, I'm almost wondering if Dave did it on purpose just to check to see that we are awake and paying attention when watching his videos.

Also, I would like to mention something else about this particular episode.
I think Dave is awesome, and I have been giving Dave a thumbs up on every video he has released since about two years back now. But this is the first video that I felt that it didn't really deserve a thumbs up. (I never dislike videos, because that is extremely disrespectful towards the uploader - In this case, I just didn't click on thumbs up for the first time in more than two years.) The reason being that I felt that Dave's attitude towards the plasma TV in this episode was a bit disrespectful towards the hardware itself, so to speak. The attitude of "No one wants it, no one uses them anymore and they are nowadays nothing more than obsolete worthless piece of junk" does not comply with my own moral standards and values, and if that is what Dave really thinks, I can then not help but asking myself:

1. When Dave saw the plasma TV in the dumpster, why did he go through all the trouble of bringing the 50 kg beast into the lab? He obviously doesn't want it because he has no space for it and it consumes too much power, and he doesn't show much interest in repairing it either. So why did he take it then? It doesn't make any sense.

2. How does Dave know that "no one uses plasma TVs anymore"? Has he asked around to see what kind of TV technology different people all over the world are using these days? I for one prefer plasma TVs over any other kind of flat screen technology for a number of reasons, and I'm sure I'm not alone in this.

3. How come Dave doesn't mind salvaging parts from the TV and throwing the rest of it to the trash which will then eventually end up in the landfill (why not take mother nature into consideration for a change?), but he's unwilling to repair the TV even though replacing a few capacitors in the power supply will actually take a lot less time than it takes to salvage most of the boards (or at least some of them) for parts? I can understand that he doesn't want to keep the TV for himself due to the power consumption etc and that is fine, but why not fix it by replacing a few caps and then put it on eBay with a starting bid of a buck or so? Then it will end up in the hands of someone who actually appreciates it and can find some use for it. At the same time, Dave has earned a few bucks from selling the TV in a working condition. So in other words, it's a win-win situation. Now isn't that a lot better than having most of it going to the landfill?

I have noticed this disrespectful kind of attitude towards obsolete hardware in some of Dave's previous videos as well. I can also say for sure that I am definitely not the only one who has noticed this, because I have seen other people point this out in the YouTube comments for other videos, and it's easy to see that people are in agreement considering the number of thumbs up these kind of comments have gotten.
One of the better episodes I've seen lately is episode #722. It looks like Dave is in his best mood in that episode, and he delivers a cheerful presentation and has a very humble attitude towards both his viewers and the hardware that was inside his mail. But I must say that I was a bit disappointed when seeing this plasma TV episode because of Dave's seemingly unwillingness to even lift a finger to try to repair the TV, but instead planning on killing it completely by taking a few parts out and sending the rest right off to the landfill, just like that. 
Come on, Dave. You could at least try to replace the caps and (if needed) do some basic troubleshooting like checking the voltages for ripple etc before binning the whole TV.

I think that the message Norcal715 delivers at the end of almost all of his videos is a very nice one: "With your help, we can keep these things out of the recycle bin and out of the landfill."

Dave if you'd like to have fun with giving this panel a fitting funeral as it's already dead....

Interesting post. However, the TV is not dead. Look at 18:49 in the video. There you can clearly see that the TV powers up and is even showing something on screen. That is not what most people would refer to as being "dead".
If you are referring to the plasma display panel itself... well, there is no evidence of the plasma panel in that TV being dead. On the contrary, it looks like there is nothing wrong with it at all.
The flickering shown at 18:49 could of course be caused by the camera as well, just as when filming CRT screens. But Dave did mention that the TV screen is flickering so this is not very likely to be a 'camera vs TV refresh rate'-kind of issue.

[calin]

I have a Pioneer Elite - KURO PDP series series 60 inch i got in 2005 .. it was reeeeaaaallly expensive but the thing still works as it worked in day one and the image is something not too schmozze at. The LED TV I have (bigger and way cheaper than the Pioneer was) still does not have the same nice image and blacks that the plasma has. All in all I can say the Pioneer still stands after almost 10 years ... Heck I just looked on ebay the same odel still sels with soething between 2000 to 4000$ ... I did read some crap "specialist" review that this was the bentley of plasma TV's but really !!! still 4K .. yeah I paid more than 4K on it back in 05  

[Tek_TDS220]

I took a look at the Samwha website looking for a datasheet for their caps, but I couldn't find anything.  These things fail so regularly that I wonder if they have a guaranteed maximum lifetime?  Maybe they have a lifetime chart with time on one axis and temperature on the other.  Companies like LG and Samsung use these caps to ensure that the electronics they sell will only last a bit past the warranty period.

[JoeN]

yeah I paid more than 4K on it back in 05

Doesn't matter until there really is 4K.  4K monitors are one thing.  4K content is another.  I expect real general availability of 4K content is still 5 years away.  Who cares what the monitor can do until I can watch Raiders of the lost Ark on it .

[RetroGameModz]

Companies like LG and Samsung use these caps to ensure that the electronics they sell will only last a bit past the warranty period.

I wouldn't be surprised if that is the case. Planned obsolescence; it's still happening today.

[JoeN]

1. When Dave saw the plasma TV in the dumpster, why did he go through all the trouble of bringing the 50 kg beast into the lab? He obviously doesn't want it because he has no space for it and it consumes too much power, and he doesn't show much interest in repairing it either. So why did he take it then? It doesn't make any sense.

I was thinking that myself. I think George Mallory can provide the answer.

Maybe he is actually going to do what he said he might do - part it out.  I think those heatsinks are the very least are worth the effort, and probably all the parts he mentioned except maybe I would leave the capacitors.

[calin]

Think you got me wrong .. i was not referring @ 4K resolution .. but at more than 4000$ back in 2005.  Even by 2005 standards the price I paid was up to the roof ... the Pioneer was second most expensive thing that was in the store  . The guy that sold it was asking me what kind of business I have 


Quote from: JoeN on Today at 08:43:19 PM

>Quote from: calin on Today at 07:56:55 PM

yeah I paid more than 4K on it back in 05

Doesn't matter until there really is 4K.  4K monitors are one thing.  4K content is another.  I expect real general availability of 4K content is still 5 years away.  Who cares what the monitor can do until I can watch Raiders of the lost Ark on it .

[JoeN]

Yeah, someone else was talking 4K resolution and somehow I glossed over that. 

Anyway, if you like your set and it still works, good for you.  I love my 42" plasma.

[DanielS]

I wouldn't be surprised if that is the case. Planned obsolescence; it's still happening today.

Electrolytic capacitors have the most predictable failure characteristics.

How many other components are explicitly rated for service lifetime based on voltage, temperature and current with some parameters allowed to degrade by 20-200% along the way? Semiconductors, inductors, resistors and most other components are stable within a few percent from nominal over 10+ years unless they are exposed to extreme conditions.

[RetroGameModz]

Maybe he is actually going to do what he said he might do - part it out.

Yep, it sounds like he has that in mind, and I do agree that there are a lot of parts in there that could be salvaged. But I mean, if you're only looking for junk parts for your lab, then why go for the heaviest, biggest and beefiest piece of equipment you can ever find in the dumpster? Why go through the trouble when you could just as well stick to other things being thrown away there, like computers, smaller TV sets, printers, CD players etc etc? Things like that are much easier to handle, yet still contain a lot of parts. I would personally not go for a big-ass 50 kg 50 inch plasma TV if I was only looking for parts and had no interest in the device itself whatsoever. A few parts in exchange for a broken back doesn't sound too tempting to me. But each to his own.

[coppice]

I took a look at the Samwha website looking for a datasheet for their caps, but I couldn't find anything.  These things fail so regularly that I wonder if they have a guaranteed maximum lifetime?  Maybe they have a lifetime chart with time on one axis and temperature on the other.  Companies like LG and Samsung use these caps to ensure that the electronics they sell will only last a bit past the warranty period.

The Asian TV makers I've worked with all seem to use the same baseline for how long their TVs should run without problems - 8 years of typical domestic use. However, they can be a bit vague about the average hours per day they rate as "typical domestic use".

[vlad777]

Your digital PSU capacitors are all dead. You should replace them.

You got a working unit and you are going to scrap it? Are you shitting me?

Please don't do it.  At least replace those caps and test it , show us it works , and then scrap it.

[tom66]

...

I'm glad to see someone on here with respect for older technology. Plasmas were killed off in part because consumers found it hard to judge the improvement in picture quality in a bright storeroom. Ask almost any home theatre professional, LCD vs Plasma, and they'll say plasma any day (or OLED, a true successor - just need to get price down & more sizes) The main issue plasma had is the light output is capped to keep power requirements sane, and the screens are extremely reflective. Most people have the ability to control the light in their room (curtains, blinds, or position of the TV) but it didn't help show the TVs for what they were.

Interesting post. However, the TV is not dead. Look at 18:49 in the video. There you can clearly see that the TV powers up and is even showing something on screen. That is not what most people would refer to as being "dead".
If you are referring to the plasma display panel itself... well, there is no evidence of the plasma panel in that TV being dead. On the contrary, it looks like there is nothing wrong with it at all.

The panel is, sadly, dead (for any reasonable TV-viewing purpose) as the pixel-wide pink lines are caused by failure of the address drivers. These are bonded to the display panel and are non-serviceable. LG had a lot of issues with this on their 2007-2009 model TVs (both LCD and plasma) due to poor bonding quality (possibly solder failure.) The failure is the same as on Dave's Panasonic TV (though that Panasonic was due to the actual IC failing, rather than a solder failure.)

Part of the problem is the drivers dissipate a lot of heat in a tiny area (1" x 0.2" max, 5W or so) and most manufacturers don't heatsink them well.

Perhaps it will be good enough for someone who just wants to use it as a TV but I certainly would struggle to use it...

[Grapsus]

Not all problems in the world are due to bad capacitors. So many things can we wrong with this TV, including damaged panel or those high-voltage hybrids in which case there's nothing that can be done.

By the way many very big capacitors are not totally flat from the beginning. The only real way to tell is to ESR test all of them, if it's even possible to do in-circuit.

[Rasz]

.

LOVE your YT channel 

[DanielS]

Your digital PSU capacitors are all dead. You should replace them.

You got a working unit and you are going to scrap it? Are you shitting me?

While bad caps on the low-voltage supply may explain some of the artifacts, the flickering which is Dave's biggest reason to decide to not bother fixing it (in addition to the weight and power draw issues) is a problem either with the HV stuff or the panel itself. The flicker could be a bad panel, worn electrodes, gas leakage, current leakage, sputtering, dying hybrids, etc., all non-fixable issues. The HV caps are plentiful and look fine, so they are unlikely to be the source of flicker. You also need to keep in mind that Dave said the flicker looks much worse in person than it did on camera and from what he has shown on camera, I would expect it to translate to the screen being unbearable to look at for any sort of normal use.

Would you bother attempting to fix a 400W power-hogging TV (at least the bits that you might be able to) when you are pretty much certain beforehand that the most painful issue with it is most likely hopeless?

[NiHaoMike]

Doesn't matter until there really is 4K.  4K monitors are one thing.  4K content is another.  I expect real general availability of 4K content is still 5 years away.  Who cares what the monitor can do until I can watch Raiders of the lost Ark on it .

All you need to get 4K content is a GPU. If you're not a gamer, a $100 750 will do the trick. See all that work area once and you won't want to go back. It's like having 4 1080p monitors in a 2x2 grid, just without the borders...

If you haven't already figured it out, 4K is an integral multiple of not only 1080p but also 720p.

[JoeN]

Doesn't matter until there really is 4K.  4K monitors are one thing.  4K content is another.  I expect real general availability of 4K content is still 5 years away.  Who cares what the monitor can do until I can watch Raiders of the lost Ark on it .

All you need to get 4K content is a GPU. If you're not a gamer, a $100 750 will do the trick. See all that work area once and you won't want to go back. It's like having 4 1080p monitors in a 2x2 grid, just without the borders...

If you haven't already figured it out, 4K is an integral multiple of not only 1080p but also 720p.

Do you mean as a computer monitor, displaying games, Excel spreadsheets, possible your photo collection?  The content I am talking about are Hollywood movies and television shows and live TV/sports content.  I get it that I could run my computer on such a TV and play Skyrim, but that isn't good enough for me, at least.   You're right, though, I will probably get a 4K monitor before a 4K TV because that makes more sense.

[Ed.Kloonk]

Once I looked in an old dumpster and I found an old wino. He was annoyed that I woke him up.

[Fungus]

All you need to get 4K content is a GPU.

Nope, that's not "content".

If you're not a gamer, a $100 750 will do the trick.

I'm a gamer and I have a 750...

[Fungus]

1. When Dave saw the plasma TV in the dumpster, why did he go through all the trouble of bringing the 50 kg beast into the lab? He obviously doesn't want it because he has no space for it and it consumes too much power, and he doesn't show much interest in repairing it either. So why did he take it then? It doesn't make any sense.

I was thinking that myself. I think George Mallory can provide the answer.

Well ... Dave is a fitness instructor so 50kg is nothing to him.

Why did he do it? Maybe he was interested in salvage (he says so several times in the video).

[RetroGameModz]

The panel is, sadly, dead (for any reasonable TV-viewing purpose) as the pixel-wide pink lines are caused by failure of the address drivers.

I was first wondering which pink lines you were talking about when I read your post, so I had to go back to Dave's video to have a look. And sure enough, I could clearly see the lines now when looking at the video in 1080p on a larger display. I watched the video on a smartphone the first time, that's probably why I missed it. 

I think you might be right. Those vertical lines certainly doesn't look good, and one common cause would be a problem with the either the flat flex cable(s) which are bonded to the X electrodes in the plasma panel (they could be ruptured), or the COF on these flat flex cables (could be faulty), or poor bonding of the flat flex to the plasma panel which makes them lose contact with age. There isn't much to do in any of these cases as repairing a flat flex cable or a COF is nearly impossible.
However, a lot of people have reported fixing X address problems by simply locating which flat flex cable that corresponds to the affected area, then releasing the flat flex cable from the connector at the X address board, cleaning the flat flex cable end with a bit of alcohol as well as the connector, and then reseating the flat flex into the connector again. I would certainly have tried that if I were Dave since I definitely think it's worth a shot.

It looks like the vertical lines are happening only on either the upper half or the lower half of the picture. Some of the lines, for example, are present only at the upper left portion of the screen. This suggests to me that this is a dual scan plasma TV and not a single scan one.
Hold on...
Ok, I just checked the video again. Yes, it's a dual scan system, because you can clearly see the X address boards at the top of the TV as well, not only at the bottom. (Around 3 mins into the video.)
The lines going vertically through the screen would then have something to do with the X address bus corresponding to that portion of the screen.
For example, the lines at the upper left of the screen, those lines would correspond to the upper right flat flex cables going into the plasma panel, looking at the TV from the back as can be seen at around 3 minutes in.
There is a metal bar going at the top of the TV from left to right. This bar is partly covering the two X address boards. If this bar is removed, the flat flex cables for the X address electrodes can then be accessed. It's then possible to clean them and reseat them in an attempt to repair the TV. Definitely worth a try, I would say.
Of course, the same goes for any vertical lines at the bottom half of the screen. The cause would then likely be the corresponding flat flex cables at the bottom of the screen instead.

And the flickering is most likely because of the bad capacitors. It might be a bit unnecessary to replace the capacitors if the flat flex issue cannot be fixed anyway, so I would have a look at the flat flex cables at first and try to clean them to see if that fixes the vertical lines to start with. If it does, I would then go for the capacitors in an attempt to get rid of the flickering.

These are bonded to the display panel and are non-serviceable.

Actually, you can service them, but you would need to have access to a special bonding machine used for that very purpose, and this is not something you would often find in the ordinary workshop. So indeed, they are non-serviceable for most people.

Part of the problem is the drivers dissipate a lot of heat in a tiny area (1" x 0.2" max, 5W or so) and most manufacturers don't heatsink them well.

In the case of a COF sitting on the flat flex for the X address electrodes, it seems to be common to heatsink these chips by using the metal bar covering the X address boards as a big heat sink. These COF are then pressed against this metal bar with thermal paste in between, heatsinking the COF driver ICs.

I don't know the reason why many plasma TVs are designed like this. Wouldn't it be better to have the driver ICs mounted directly on the X address boards (with heat sinks, of course), and just have a plain flat flex cable going to the X electrodes in the plasma display panel? It would certainly be a lot easier to service these TV sets if that was the case, but there might be some design complications involved there which I don't fully understand, perhaps...

Perhaps it will be good enough for someone who just wants to use it as a TV but I certainly would struggle to use it...

Same here. I didn't notice the lines first time watching the video (sorry about that), which made me believe that the lines that Dave was talking about was the type of line fault that only shows up every once in a while. I could live with that if it's not too serious, but I wouldn't want to use a TV that has stationary lines or some other kind of continuous line failure, which is the case with the set in Dave's video.
But on the other hand, I would certainly not mind taking on the challenge of repairing it.

LOVE your YT channel 

Haha. Love you too man. 

[RetroGameModz]

Would you bother attempting to fix a 400W power-hogging TV (at least the bits that you might be able to) when you are pretty much certain beforehand that the most painful issue with it is most likely hopeless?

I certainly would, and I was kind of hoping Dave would too.

1. Because experience can be gained from every repair attempt, whether or not you succeed in repairing the device you're working on. Dave is running a video blog, so his repairs (successful or not) are shared with a lot of people worldwide. That means a lot of people, not only Dave himself, will gain more knowledge from his repairs.

2. Because you can never be completely sure about what is causing the problem before you have troubleshooted the device and verified the cause. And as long as you haven't done that, there is always the chance that the cause of the problem is something that is very much serviceable.
I personally don't like to assume things. I like to verify.

3. Because if Dave does manage to fix the TV, then not only will it be saved from going to the landfill, but Dave can also sell it on eBay (local pickup only, of course) and earn some money on it. There are still people out there who are big fans of the plasma TV technology, and a 50" plasma could sell for quite a bit of money. The new owner of the TV will be happy as well, so it's a win-win situation.

4. Because there is nothing to lose, only to win.
TV turns out to be unrepairable; troubleshooting experience gained.
TV turns out to be repairable; troubleshooting experience gained and money earned since TV can then be sold.

But I do realize that Dave is a very busy man, and I can somehow understand his decision considering he's not interested in the TV. And I'm sure there will be other repair episodes on his channel in the future anyway.

[Zbig]

Cut the guy some slack. It seems Dave's mind was already at building his new, double Xeon monster machine - see Twitter. It indeed seems a bit rushed, like he just wanted to be done with it already, but I bet, my inner child and the urge to get to something much cooler, rather than to deal with some old appliance, would win, too. I think most of us have been there as well ;-)

[VK3DRB]

Anyone notice the triangular pin 1 designators on the LG PCB's? Good engineering ! Round pin 1 designators are second class citizens compared to triangular pin one designators because triangular pin 1 designators are more easily discernible and they point to the device of interest.

[DanielS]

3. Because if Dave does manage to fix the TV, then not only will it be saved from going to the landfill, but Dave can also sell it on eBay (local pickup only, of course) and earn some money on it. There are still people out there who are big fans of the plasma TV technology, and a 50" plasma could sell for quite a bit of money. The new owner of the TV will be happy as well, so it's a win-win situation.

A quality plasma TV in perfect working order might be worth some decent money. A plasma display with unknown ownership history salvaged from a commercial dumpster room and horrible flicker and line/column glitches is mostly worthless. If it is not something obvious like ripple on the voltage rails which Dave had a quick look at with a multimeter, then the other possibilities are either busted/flaky digital chips which involves replacing a board since the chips are likely not available as loose parts, or the hybrids, which are also not available as parts (or even if they were, they are potted) so that's another set of board-swapping.

Dave's lack of enthusiasm about this potential repair is quite understandable. There is not much that can be repaired in it that would make economical sense. If he sold it as parts though, he might be able to earn $150-200, which is more than what he would likely get for the whole unit even after a successful repair without the expense of throwing parts at it and the risk of doing so for nothing.

[Wim_L]

Is it only the light beeing reflected or do those caps look bulged? There seems to be even some black stuff leaking at the top of each cap or are the caps deliberately beeing marked?

Those are definitely bad caps even though the black stuff is just a marker. (quite common on those caps, probably marked after testing) I was screaming at my monitor when Dave was talking about the caps in the high-voltage supply and didn't notice the horde of bad caps in the logic power supply.

Remember Dave usually sees the item he's filming through the screen on his camera, which would be quite small and low resolution compared to what ends up on Youtube.

[VK3DRB]

Is it really worth salvaging anything from this plasma TV?

I used to hoard electronics and when I moved house in 1986, I took 6 trailer loads of TV's and VCR's and other electronic junk to the local garbage tip. Next time I moved house in 1999, I took 8 trailer loads of TVs, VCR's, computer chassis, useless test equipment and boards to the tip, vowing never to hoard again.

Eventually I learnt it is better to buy new parts than to take up so much valuable real estate with electronic junk box stuff. The economics actually makes sense NOT to hoard just in case you might need something one day. High voltage capacitors are the exception, because they are generally hard to get.

[aveekbh]

Remember Dave usually sees the item he's filming through the screen on his camera, which would be quite small and low resolution compared to what ends up on Youtube.

Although, to Dave's credit, he usually puts in annotations in post-production (in the video itself) or even in YouTube once he spots something that he missed while filming.

I totally understand Dave's reluctance to try a repair. Like he said, some of the boards are worth salvaging for components. I hope once he's removed the boards, I hope he will dispose of the panel et al responsibly. Dave is ecologically minded, after all.

[Fungus]

I totally understand Dave's reluctance to try a repair. Like he said, some of the boards are worth salvaging for components. I hope once he's removed the boards, I hope he will dispose of the panel et al responsibly. Dave is ecologically minded, after all.

If it *is* the column drivers as some people have suggested then it's probably not fixable (without spending a lot of money).

OTOH I think he should have tried swapping those caps just to see what happens. Where's the sense of curiosity?

If it starts working perfectly then... I dunno. Put it in the lobby with a sign on it saying "fixed! working!" and see what happens (leave a GoPro filming it or something). Have some fun! Maybe somebody will use it.

One time I replaced the ugly bathroom cupboard/mirror that came with the house for a new one and I left the old one downstairs with a sign saying - "Haunted mirror - we saw dead people in it! Do not take to your house!!" to see what would happen

(Answer: We got bored and went home after watching it for 20 minutes, I guess I'm not cut out to be a PI).

[DanielS]

OTOH I think he should have tried swapping those caps just to see what happens. Where's the sense of curiosity?

No need to replace them in a (mostly) working device: put a scope probe on the output rails and see how clean they are. If there is only 100mV of ripple on the 5V rail, then you know without having to swap caps that caps on the 5V rail are most likely still good enough regardless of how bad they might physically look and you are better off looking elsewhere for more likely suspects.

I recently repaired a 24" LG LCD. The caps on the 12V rail had leaked and were from the infamous Samwha WB-series, but there was only 100mV of ripple on it. I replaced them anyway with Panasonic FM which have significantly better specs just to spare myself the trouble of potentially having to re-repair it because of them later but on the scope, this made practically no difference despite doubling the total nominal capacitance on top of that. Capacitors on the 24V rail were in far worse shape with 1Vpp of ripple and wild fluctuations (3Vpp if you include switching noise peaks) that went down to a much more steady 200mVpp (2Vpp including switching peaks) after putting new caps in.

My point: if you have a (kind of) working device, measure before blindly replacing components - spare yourself the trouble and cost of replacing parts that most likely have nothing to do with the immediate issues until you have identified repairable high probability suspects. If you do not find any such smoking gun, you may still choose to try blindly replacing caps afterward but at least you do so knowing there is a fair probability it won't help much, if at all.

[tom66]

In the case of a COF sitting on the flat flex for the X address electrodes, it seems to be common to heatsink these chips by using the metal bar covering the X address boards as a big heat sink. These COF are then pressed against this metal bar with thermal paste in between, heatsinking the COF driver ICs.

I don't know the reason why many plasma TVs are designed like this. Wouldn't it be better to have the driver ICs mounted directly on the X address boards (with heat sinks, of course), and just have a plain flat flex cable going to the X electrodes in the plasma display panel? It would certainly be a lot easier to service these TV sets if that was the case, but there might be some design complications involved there which I don't fully understand, perhaps...

The main issue is the  number of connections. A 1080p display will have 5,760 address driver outputs. For a screen about 45" wide (~50" diagonal) that's going to be 0.2mm between each address driver output. Difficult to do that with conventional PCB connectors and layouts. So the PCB is fairly cheap, and the TCPs themselves have the complex layout density. I guess it's cheaper to do that.

The heatsinking that manufacturers use has been reducing year on year as manufacturers pushed for improved efficiency. Modern address drive forms less than 30W of a PDP. Problem is jumping to 4K would double that, and also add ~50% more sustain losses, already a push for 1080p displays with lower brightness trying to meet energy regulations.

[haxtormoogle]

Moment I saw the caps on the low voltage power supply I was saying to myself "YES fix them caps dave! FIX them!!!!" Then the rest of the video was pure torture waiting for him to mention them, By the end of the video I was yelling at my computer! The caps Dave! The CAPS!!! Why didn't he attempt to fix it?!? What if he replaced the caps?!? 

[Pentium100]

They still make Plasma TVs and I bought one (LG 150cm) a three months ago. The reason for buying a plasma instead of LCD was this:
1. The plasma TV was cheaper than equivalent size LCD
2. The black levels are better.
The black levels are not that great, but I read on a forum that it is possible to tweak the voltages to get the black level down - something that I will do after the warranty expires. It also has the white level power limiting, but I guess nothing can be done about that (since that's more likely to be done in software so getting a bigger power supply would not change anything).

The TV actually does not use a lot of power, 150W or about the same as a LCD of the same size. However, I do not really care about the power - as long as it does not trip the breaker I'm fine, especially since I watch that TV probably an hour a week on average. I care a bit more about the power consumption of the devices I keep on all the time (servers, bitcoin miners probably use 1.5kW continuous).