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You might think you know how film capacitors fail and degrade in capacitance over time - self-healing due to surges, right? WRONG!
Capacitor expert and AVX Fellow Ron Demcko confirms what's really going on after a teardown of some failed and one good polypropylene X class capacitor.
00:00 - Teardown of a some failed film capacitors
00:52 - Self Healing and drop in capacitance
01:44 - Capacitance Measurements
02:15 - Teardown of a new Suntan brand polypropylene X2 film capacitor
03:03 - Different failure modes based on size and winding pressure
05:52 - Unwrapping the film
07:51 - The film inside a NEW film capacitor
09:19 - Teardown of the FAILED uTx brand heater capacitor with half capacitance
10:06 - How Schoopage and the end pin terminations work
12:23 - Teardown continues...
12:45 - WOW! What on earth is this?
14:54 - Elecami Wolf also did a teardown
16:05 - Teardown continues...
17:01 - Separating the film showing both slef-healing and extensive metal film corrosion
18:29 - Another uTx brand failed film capacitor from a Corsair PSU, with 90% loss in capacitance!
Elecami Wolf Youtube Channel: https://www.youtube.com/c/ElecamiWolf
19:55 - Let's call an expert! Ron Demcko from AVX tells us the REAL REASON for the failure!
It's moisture ingress and corona demetallization!
Full discussion with Ron Demcko:
https://www.youtube.com/watch?v=9V99J22aiLE
Metallized Film Capacitor Lifetime Evaluation and Failure Mode Analysis report:
https://cds.cern.ch/record/2038610/files/45-56-Gallay.pdf
Forum: https://www.eevblog.com/forum/blog/eevblog-1486-the-real-truth-why-film-capacitors-fail!
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#ElectronicsCreators #Capacitors #Teardown

Ah hello hi in a recent video. If you haven't seen it which i i'll link in we uh repaired an alec um heater and a spoiler alert it turned out to be a failed x2 uh cloud class metallized uh poly put the kettle on uh filter capacitor or in this particular case. It was used as a dropper resistor for a zener and by the way don't mind the voice and music in the background. If you can hear it i'm just like on hold with a bank.

So yeah. It's going to take an hour. So i thought i'd shoot a video. So that was this one here and um.

I tried to get a replacement one from another uh power supply and it was a corsair vs 650. Power supply which had failed and no this wasn't the reason now for the fail um. But i got the actually the exact same one out of it and both of these had drastically dropped in capacitance. And that's to be expected.

If they've been surged overload. Because that's how metallized self healing polypropylene uh. Probably put the kettle on capacitors actually um work. If you put an impulse into them.

Then they'll get a little energy discharge inside of there. Which will then have a little plasma arc. And it'll just vaporize the metal and then it uh it won't short out because that metal is vaporized. It'll actually just form an insulative hole.

There and it retains its capacitance so it won't short out. But do this too many times and you lose too much square area of your capacitance and uh. That's how these self healing caps work. Anyway.

A few people asked could i actually take these apart put them under the microscope. And see if we can see any damage well um. I don't know is the answer. I guess we'll find out so before we get medieval and sas.

We'll just measure. It here here's the uh failed one from the alec heater at one kilohertz. 1035. Farad.

So that's less than half of the 220 uh nano farad uh nominal value in there and the other one is absolutely plummeted 109. 192. Nanofarads wow more than the order of magnitude. And the esr is up to you know oh looks all over the shop.

Yeah. The esr is better at uh a hundred kilohertz so i'm just testing this on a good one. This is a uh got this from j car. This is a sun tan.

I took the side off it there and you can see that yeah. It's pretty well the potting compound has gone all the way in there anyway. I forgot to tell you this is a utx brand and we do actually have uh. The data sheet uh for this one that we're going to attempt to tear down.

It's in chinese. But we get the deal in this particular case. It's a polypropylene jobby. So they're metal uh metallized film.

They just call them film capacitors is the uh is the generic uh name. And it's got a metal sputtered layer on in this particular case. The polypropylene film and there we go so we expect it to be wrapped in there. Like that the interesting thing is is that you can actually get different failure characteristics.

Internal plasma. Um arcing in there um. When they're tightly wrapped or loosely wrapped. So a tighter wrapping.

Actually gives you a different effect in the way that these things fail apparently so yeah. That's interesting so let you know a smaller one like this a two to four they might be the same voltage rating. But a uh 220 nano farad in this size might act and survive. Very differently to a the same one here 220 nanofarads in a much larger size because this could have a thicker metal layer and a larger or a less tight wrapping there so less tight pressure uh between the metallized um surfaces.

So yeah. It can make a difference apparently well there you have it i just accidentally broke that off so that answers that yep they are rolled exactly like i suspected. I don't know why the wrap looks like that it's got maybe that's just part of the foil manufacturing process. But you can see that it's got stripes on there which makes it look like you know it's stacked in this direction like this it's like a one stack two stacks.

But it it doesn't you can clearly see the wraps in there so maybe that's the way to do this sort of tear the legs off looks like we haven't done too much damage right so i'm just testing how to get these things apart. And then looks like that has a contact. Which then goes over into the middle. Okay so let's get medieval.

Oh i can't nope. I know i'm gonna need a bigger boat. The potting is too good the way. I did it last time is to kind of like yeah get in there like that.

But yeah. This potting hasn't really taken to the foil so potentially ah yeah. There we go we can't actually get this off ah bobby dazzler you're that all right so. You just have to be gentle getting the end plates off.

Although the em damage is not gonna be in the ends. It's going to be in the middle somewhere. So i assume there's nothing but pressure holding them together. I don't think they'd apply an adhesive when they wrap them i think they just wrapped them.

And bob's your uncle all right can we see. Where the wrap starts is that is that it so that's an additional plastic wrap maybe we can okay yeah. We can get under all that don't worry. I'm not going to stab.

Myself. I am. A professional ah okay. There we go is it starting to look metallized.

See. If i put a bit of light under that you can see ah. It's starting to get more metallized isn't it looks just getting more and more that's that's interesting so you've got to remember. This is a brand newy that'll pull it apart okay.

So this one should not have any fails finally got through to the bank by the way uh have a look here i put some gloves on so now you know that's not the metallized layer. I expect right. But there's obviously something i expected like a solid not not to be able to see through it at all so you could say that it's getting more and more maybe we're not actually into the cap that's just not what i was expecting at all roll and roll and roll in and wow. Oh here we go.

This is what we expect there you go so several layers in oh whoa hello. It's like you got like bad. Toner or something like that um. Yeah.

You really have to have the light behind. Here. There's um stripes by the way. That's just my um adjustable color temperature.

Um studio light and turn. It. All the way. Blue.

Look. At that isn't that neat ah here we go come on is that just another. I don't know that's okay. Oh hang on oh that ripped very thin polypropylene layers.

Oh god it's doing it again no it just keeps just keeps going keeps tearing like that yes. It's getting frustrating am. I back onto a perfect roll. Now yeah you can see one metal layer.

There's some pull back there. And this is in the construction. You can see it in the color. There.

But yeah. They do actually tell you the pullback distance in some data sheet. It has a specific name. I'll spear the gory details.

Yeah. I'm curious to see what happens when it gets to the middle. I presume that there's a some sort of small core. It starts on unfortunately unless you start the un rolling process perfectly.

Then you're gonna come agata haven't peeled off this these side bits properly. So ah yeah really ripped. It as i've so that really wasn't wasn't the way to go about it was it we're not done yet folks. That's not all folks um.

No we have to keep going. That's one side and then the other you can see the other side clearly poking through there so and then and then you can see the polyprop film. You can see the reflection. The poly pop film on top of that so they manufacture this as a completely insulated.

Thing. It's almost like powdery isn't it it's going to be really interesting to open the um dead. One and see how it drops that amount of capacitance. It must have like i can't imagine how many like huge holes.

It must have in there when you talk about these things you know blowing holes in them and self healing and stuff. It has to be on a small scale. I've still got a ton of wrap left in here. Oh.

It's torn again. It's hard to unroll these things without tearing. You're getting the idea. What's inside one of these puppies okay well i certainly don't need these gloves.

So it all seems very clean. So that's good stuff going this doesn't end it does not end. This is too much fun. There's an art to unroll in these and i don't have it yet.

This is my first one i'm losing the will to live help me. Larry help me you have to be in on the dumpster joke on twitter to know who larry is well you can't say you're not getting your money's worth in your capacitor. I can't come on there's there's got to be nothing left in there. There's more layers.

No i i think we're done. I can have a go at uh taking apart the failed one like surely if it's lost half of its capacitance right you'd expect to see tons of like huge blowholes in this foil um. Because it's a you know. It's a wrap like it it's a square surface area thing.

This is going to be intriguing. I don't know how you can lose half the capacitance in there okay so here's the utx one that's lost half of its uh capacitance. So this is the one from the heater gonna have a crack literally there we go of course. They're all going to have varying amounts of pot in and stuff like that but there you go.

It's basically the same construction as the other one so these are different brands really adheres to the casing way better than the other one this one seems like bonded you can see here. How they do the end contact and uh. This is called shoopage named after max shoop. It's kind of like a pasty mixture kind of stuff that gets put after they put the wrapping on and then the contacts extend all the way to the edge of the film on each side of it so you've got one that extends all the way over here one that extends all the way here you've seen that before with that overlap gap uh thing in in the film.

And then um. All this pace. Which is uh. It used to be like a tin lead um.

Kind of just like a solder uh paste. But of course ros compliance. They don't have the lead. Anymore.

So it's like a tin zinc or something aluminium uh maybe. And yeah they mix all this stuff together becomes. I believe some sort of like a pasty type thing and you can see the film in here. But you can see how the end here this has actually formed all the impression here because it's it's just got inside each like a wrap of the film.

And it's just it's just peeled off like this. But this is how they do the end contact. There's not just one end contact point. Because if there was then you'd have the giant uh.

You know roll like this and then you'd have huge self inductance in there. This is why each layer is effectively um stacked. So that uh. Yeah.

You get low inductance um. In these capacitors. So. That's how you can lower the manufacturing.

Cost of this of course by wrapping things when you have machines that rotate and wrap. It's you know it's very once you've got that refined it's you know it's very quick and easy to manufacture like huge number of plates like this. But this is how they make contact and yeah that stuff just peels off when you actually break that so you know this is the uh polycarbonate uh probably put the kettle on film. And it just sort of gets in between all the gaps and then the pin is just uh embedded in that as well and they probably you know bake it at a temperature.

And do whatever um to make it um set in there. But there you have it that's stupid. And that's why it appears to break off very cleanly like this because like it kind of sort of adheres to the metal uh layers that are on there but when you break it apart. It's just quite soft and it's just well it looks like it it's like just totally sheered off it's just peeled away from the plastic film and then the metal layer inside there it's neat really neat process.

I like it shoe beach that's that's too perfect. We've got the same stripe effect. Nothing looks as good on camera as it does with your mark one eyeball. I think we're gonna have to sacrifice some outer layers here needs of the many outweigh the needs of the few same sort of thing or much different secret sauce between the manufacturers.

It's interesting. How oh yeah. There we go whoa surely that's oh is this what where is this it is this. It.

This is very consistent look at this look. At this. Wow. Ah.

Hello. This is all the way through. This is not my um. Maybe.

That cut or that cut. There that that that could have been my knife. But look wow look at that whoa look at that huge hole there. But it's interesting this strip down like this looks like i don't know ink lots right if you're a psychologist.

How do you feel dave tell me about your mother. What's the first thing you see in these in these ink plots. It's unusual that this pattern is consistent all the way through what the heck and look we got tearing again surely i didn't gouge it that much yeah maybe i dug into it there okay. What's all this squiggly stuff in the middle.

It's almost like it's split so we're getting smaller and smaller gouges that's what we'd expect until they go away. So that's that's obviously my uh heavy handed medieval technique this pattern is still all the way through it if you want to see the other side looks. Exactly the same okay so this one's lost half of its capacitance. This is not what i expected like if i expected you know i thought i'm sure it will maybe see something but i i really didn't know what to expect.

But it certainly wasn't this. But also all of this blotchy stuff here is another thing right that like that's another thing entirely. We just did not see that on the good capacitor. But once again you need like a control capacitor.

The same model the same brand everything to pull apart. But there's something like that is just weird here's like the blow here's like the holes. You know. But unfortunately we can't get their film apart right.

There's nothing visible on the surface. So whatever's happening. It's happening inside the film that this is all blotchy and there's holes everywhere right and thanks to one of my viewers elekami wolf. Who saw my live show where i uh previewed.

Some of this um tear down check out his uh channel. Here. It's um. It's actually really good at only 153 subs.

It deserves a lot more subs. There's like great tear downs and all sorts of stuff on here. So i'll link in down below. He actually had the exact same utx branded cap and pulled it apart.

And this is what we get and this is like more kind of what i expected i expected like big sort of like you know blow chunks taken out of it you know from like the impulses and stuff. But you can see it's very sort of blotchy in there as well and here's another shot here and this is you know kind of what i expected like big chunks taken out. But he's unsure whether or not it might have been the peeling process or something like that. But yeah.

It's anyway. It is very different even though exact same brand uh and model cap as my one and i've got that wiggle wiggle. Yeah through the middle of it we don't see any of that here. But yeah.

He's unsure if this was like um. Like when he teared the um film apart and like it just like peeled off blotchy and stuff like that anyway. It's very interesting thank you very much that is quite different to my one it doesn't look like anything's jumped through the uh. The top and bottom polypropylene layer whatever's happening is happening.

Within. You know how they manufacture they're real like this um. You know so they make it that that that's your capacitor. But it's all to do with the difference between these two.

But why is it all blotchy and and the squiggly lines. It's just all the way through did i physically stress. It and it's and it's torn it's stretched the polyprop and that's cracked. The metallization was that done due to my heavy hand and this it's hard to see how it would be or wiggly wiggly.

Yeah like that and also that doesn't explain the blotches so so all i can tell you this is certainly very different to the control one that suntan brand to be 100 sure though i would need another utx brand perfect. I i tore it there and you can i separated the layers look at all those blowholes wow. Gotcha right surely that has to be what happens. But um yeah like when i did my last video.

I i published that yeah. It's actually like it forms a little plasma in there when it over arcs because it vaporizes the metal. And it looks like it does vaporize the metal and that causes a uh decay in your capacitance. But it doesn't short out it just blows.

These things up like it just like the metal is just gone right the metal is just vaporized away. And there's just uh pressure in there and it just i don't know how it escapes. But it's just right it's vaporized away and this is the self healing nature of these capacitors. The last thing you want right your capacitors.

If it shorts out right bingo your uh product's going to go banksy right when they get an impulse like this it damages them and causes a degradation in the capacitance that is clear as day wow that crack though like all the way crack all the way i don't know leave it in the comments. If you can explain that uh in fact. I do have access to a capacitor expert. I might ask him these are just like kiama size blowholes.

This is insane. But then again to lose half the capacitance. I like you really have to lose like half your material here's the next victim. This is from the corsair uh power supply and exactly the same capacitor.

Exactly the same model everything's are the same. I believe so apple's apple's comparison. But this one has lost or over 90 of its capacitance. So the other one we saw you know roughly half the material was missing will we see like 90 of the metal missing from this one.

Let's find out is our layers are we getting into the good stuff. The crack again look at this but the crack is bigger maybe. That's just tearing from the unwrapping process. It just seems weird that it's like only a small section.

Though doesn't seem right i mean look. There's hardly anything left in here. But that's oh yeah. So we just separated separated the two layers.

There maybe i've unrolled the wrong layers. But then you've just got you know holes like that and what the heck you know like this this is not peeled off somewhere else right. There's no matching thing on the other side so it's almost as if this has happened within the film. But yeah.

It's got this weird cracking like there's just nothing left in there. Look. How does this have any capacitance at all it's got that weird gap. All the way down.

I can't see how that's a result of me unraveling this anyway. I think we've seen enough. I think it's time to uh phone. A friend phone.

An expert and see what they have to say about this okay well as it turns out it looks like i'm wrong. So. We have an expert here who's joining us ron demko from avx. Thank.

You ron you're going to tell us what i've got wrong because i thought this was a self healing issue. But you don't think so yeah. I think we could we could give you some details on on the real event. All right.

Thank you so. What's your role at um avx. How long. Have you been there.

Well. I just. Passed. 40 years.

Yeah. Wow. Yeah. Well you know.

It's funny. Though. Because the company changes. So.

Every three or four years. We buy a new division. So at one point at time it was just capacitors now it's antennas connectors uh modules. A whole bunch of other things.

So yeah. Right i work in a small group in r. D. And we do engineering support things like that got it.

But you're mostly. But you're the capacitor guy right you're in the capacitor yep that's your specialty 40 years in 40 years in capacitors well yeah different types glass tantalum electrolytics ceramics tell us your opinion what am i seeing here what do you think this problem is because you don't think that it is uh being destroyed by impulses on the mains that's right yeah. Well i think we we should start going back and looking at the part. So mainly these parts are non hermetic.

They're using a low cost epoxy. So you know they're very cost effective easy to use easy to choose so it's a probability that moisture got in in the application. And then that moisture was trapped with that non hermetic case. So what we have well there's also another scenario.

There could be poor drying in the manufacturing process and possibly materials where you know water was put in there that's very unlikely so i think what we've got is a couple of easy explanations uh of course those small holes. Or maybe. The big hole that you have up on the upper right. There right is that's a result of actually self healing.

Okay. So that's the vaporization as you can expect now when we start getting into the other area. We can explain things kind of easily as you roll this thing out from the left to right or right to left. You'll notice that there's a variance.

Some of that variance is due to the difference and the connectivity from the shoopage on the termination to the actual electrode. So at one point in the video you showed a very light uh background with some speckled. Um scenarios and that was just moisture and a high resistance scenario. But what we're seeing here is in the the the crack lines uh the the lightning bolt.

Looking thing. Yeah. That goes right that almost went through the whole thing you're having this electro uh well this reaction of the moisture. And what's occurring is that you're getting a uh.

A moisture effect. That's actually causing the electrodes to change uh. They're getting more resistive. They're getting some some migration or movement oxidations changing resistances.

So. Those voids are most likely to some extent like a micro healing or a impulse degradation that's how it explained that lighter center section. And the darker blotches are the most likely a result. Yes.

Yeah. Those are going to be mostly a result of end termination. Corona type effects something on that order um. So it's always difficult to comment.

Maybe what fifteen twenty thousand miles away or so yeah. But um and not having dealt with the parts. But i think that's pretty much the scenario. It's definitely a moisture event.

So will the moisture like eat away at the metal will it like actually corrode the metal. And what what sort of metal are we talking about here for the metallization layers well in some cases. There there's zinc. But this most likely is not the case.

It's usually aluminum. It's probably on the order of 100 angstroms. The dielectric thickness itself. So the film itself is probably in the order of maybe 1.

To 20 microns. Something i like that so it's a wonderful part when they work well. And i suppose it worked in a sense. It worked well this one is only a year old.

See that's the thing. That's why because when when i think of moisture ingress. All i think of is like old school reefer paper capacitors. Which are famous for you know getting moisture ingress they crack the cases crack moisture gets in it is absorbed by the paper and then when you go switch it on you've got this big conductive path that just goes boom and the magic smoke escapes um.

I i just didn't expect that this that moisture ingress with film caps after like a year in you know. It's the actual product. It came from is only a year old. Yeah.

I can make a couple of guesses on where the um moisture came in and that's a big issue. Choosing the right epoxy is is tough and i'm sure these guys build great capacitors it it could happen to anyone. But um. The right material system's the it's a it's a real secret right yeah.

And is that something you can test like after you've constructed them yes. That's a very good point. So how do you do that what we could do yeah. We'd put them on a moisture.

Humidity test uh you may be maybe it would be good to have 40 degrees c. And i don't know 40 rh maybe another 40 degrees c and an 80 percent. Rh brutal humidity cell and then do an 85 85 cell and what we would look at we would look at the degradation of capacitance across time and that would tell us a lot of things about uh. What's happening within the device uh that would probably go in with edx and we would do some uh x.

Ray uh evaluations of of where the material systems have broken down and and constituency of water etc. Because as you said some of those small little points in there might be self healing is that certain those that is is that the size of hole. You'd expect from self healing. As from an impulse.

Thing. Yes. Yeah. It's pretty neat too to uh to throw these on a sample scope and and apply i don't know a couple of different signals to them and you'd actually see some noise occurring.

When we have self healing events. So that'd be a neat though i don't know noise. What sort of noise are you talking about well you'd actually you know apply maybe full voltage at maybe a moderately high temperature. And you might actually see some failures punching through and you'd actually see some variation in the applied voltage of the part as this thing coronas so when you get those little micro uh healing points.

You actually vaporize that electrode material and as it cools it precipitates around that failure site. So if we could blow this up a little bit more with the sem or something like that we actually see a little dark halo around that white point of failures. So this large hole here. I don't think that's a blow.

I don't think that's a self healing blowhole would it would you get one that large well you could it depends what hits it i think that's maybe more unlikely maybe i've torn it there is it possible that i've torn this when i've taken it apart. Yeah. I think he did a good job on the dpa. But i think we might have approached it a little bit differently right okay well it was my first time okay so when you like the ones that where we tour down.

Here. Where's the ceiling point is it the potting is it when they potted is that what they're trying to do is that they're trying to seal. It as best they can yes yes uh it would possibly be at the perimeter of the metallization to the uh encapsulate right okay and then through the uh shoopage on the side really it'd come in through the side. It wouldn't come in through the actual film wrap would it because i would imagine that that's pretty sealed.

It's correct that's correct right it would be at the interface of shoepage or some errors or voids and stupid thank you very much ron. This has been awesome um. I was completely wrong i just went into this video with the mindset that it's all self healing. And i didn't think about moisture.

Who knew right and so this is going to be a surprise to a lot of people. I think that surprise. It's no no well it it introduced something to think about um is like should as electronics designers should we avoid you know if we use them in these sorts of applications um. We're like a capacitive dropper should we avoid like a no name brand sourced cap for this reason or are they all pretty good or i don't know if i could comment about that they can't comment.

Okay just. But i have to say films are a good part to use and it's probably a great application for that all right. It's been awesome thank you very much ron.

By YTB

25 thoughts on “Eevblog 1486 – what you didn’t know about film capacitor failures!”
  1. Avataaar/Circle Created with python_avatars 777anarchist says:

    Is it possible for the moisture to get inside the cap prior to potting? It wouldn't have to be much to cause the damage, I guess.

  2. Avataaar/Circle Created with python_avatars bigjd2k says:

    Cheap X2 caps are definitely worse than good brands. Had big trouble with them at work about 15 years ago, purchasing loved this brand because they were cheap but sales hated the failure rate! However be careful with the peak currents in your circuit during normal operation, especially when using them as decoupling caps for PFCs etc as they can run hot due to their ESR and degrade fast! Especially if the ambient is hot. If you don’t mind spending more, specify a good make of class X1, they are way more robust.

  3. Avataaar/Circle Created with python_avatars SignallerK says:

    Do we have the same issue for standard metalized poliester (pe) caps too (those red ones which you can find in different devices)? Because I used to find them with significant capacity degradation, but I never had an idea of degradation reason.

  4. Avataaar/Circle Created with python_avatars Rubus Roo says:

    very interesting thank you

  5. Avataaar/Circle Created with python_avatars Cyrus Brinkworth says:

    corona ….again! dam!

  6. Avataaar/Circle Created with python_avatars Darren Young says:

    I see “capacitor art” as something that needs to be done, compare good and failed film caps in a post-modern, avant-garde, abstract kind of way. Just add some more fancy words to describe the style and auction it, starting price matches the cap, 1k is $1,000, 10k is $10,000. Make more of the lower values and only a couple 1M ones. Use a pseudo-name, say you’re Italian, Pico Farad.

  7. Avataaar/Circle Created with python_avatars Bill Kerr says:

    There's nothing like talking to an expert.
    Now take the squiggly line one and drop it casually outside of Area 51 where an unofficial visitor will find it. Makes perfect "alien writing".

  8. Avataaar/Circle Created with python_avatars CERG LABS says:

    Thanks for this one!

  9. Avataaar/Circle Created with python_avatars 1975RStefan says:

    Maybe moisture got diffused into the layers?

  10. Avataaar/Circle Created with python_avatars Peepee Poopoo says:

    "poly put the kettle on" lmao. acting like polypropylene and polyester are in any way similar is so disgusting to someone who knows about chemistry… "FILM" is a very ambiguous term!

  11. Avataaar/Circle Created with python_avatars Hola! SashaXXY says:

    Are there caps that are built specifically for moisture resistance? I had to make some circuits without capacitors recently because I need to use them in a high humidity environment and they kept giving me trouble. IC's have held up better for now. But I would like to use capacitors eventually…

  12. Avataaar/Circle Created with python_avatars Max Myzer says:

    maybe too high of current and it tried to short across the 2 sides? idk enough about caps to say

  13. Avataaar/Circle Created with python_avatars Johnne Luchsinger says:

    I love the Pulp Fiction 'Get Medieval' reference though it may just be what Dave says when he is out to destroy yet another device!!!

  14. Avataaar/Circle Created with python_avatars Kyle Rhaged says:

    This was super cool!!! Now I wanna take apart my pulse rated capacitors that seem to have lost 30% of their value. Wonder how many holes they have!

  15. Avataaar/Circle Created with python_avatars Jeremy McMillan says:

    Looks like a cool tshirt graphic to me. Kinda surf-themed I think.

  16. Avataaar/Circle Created with python_avatars GHILLIES ARCADE AND MORE says:

    Cool

  17. Avataaar/Circle Created with python_avatars neilw2O says:

    Some years back, same problem. Testing at various clean, spike free, AC voltages up to 270AC, 50Hz, I measured reduction in capacitance at about 1% per week, proportional to applied voltage. This was in a product I designed previously, using charge pump voltage stepdown. It was in certain brands. I heard unconfirmed rumours relating to an unhappy chemical engineer assisting this problem. Same with bulging electrolytic capacitor, olive green. Different brand. No problems. Wima are winners.
    Further to that, start off with 2 new bum brand ones. Now using AC kill a capacitor for a week, then unroll both an compare.
    There are a self healing variety that have a grid instead of a film, and the blowholes from spikes are much smaller. Noticed in larger type motor start capacitors.

  18. Avataaar/Circle Created with python_avatars Tyler Hayslett says:

    I found it interesting that the failed capacitors had much better epoxy/potting compound adhesion than the good cap. Maybe the moisture cant get out?

  19. Avataaar/Circle Created with python_avatars RavenLuni says:

    I use these in the multipliers for my ozone generators. Should I be worried?

  20. Avataaar/Circle Created with python_avatars Qs Tech Service says:

    Holy cow look at those lightning strikes pattern's 😳
    It made a record of them White lightning strikes …

  21. Avataaar/Circle Created with python_avatars Ivan Kocher says:

    I hope that someone with access to a electron microscope can also open one of these caps and show us how it looks around the healing zones.

  22. Avataaar/Circle Created with python_avatars zyblex says:

    Thank you Ron! I enjoyed the video with your tear down and educated guesses Dave but the expert view was delightful (and actually useful for my day job) 👍

  23. Avataaar/Circle Created with python_avatars Gregory McCoy says:

    This was a great discussion. I learned a lot.

  24. Avataaar/Circle Created with python_avatars Proluxelectronics says:

    What are them big components with wires sticking out, something from the 80's 😆😆

  25. Avataaar/Circle Created with python_avatars Hola! Mihai Achim says:

    in college we were proudly presented with the "advances in technology" that allow the construction of smaller and smaller capacitors at increasing capacities but shortly after graduating I realized that bigger is almost always better … so to speak

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