Is this capacitor deformed?

[timb]

I had to open my Tek DMM4020 to fix a broken clip inside the front panel. Looking at the main PCB, I noticed this capacitor. It appears deformed, but it's not leaking.

Is that some weird shape I've never seen before? Does it contain a miniature black hole causing it to implode (and trapping the electrons in a singularly)? Or is it a dud?




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[rickselectricalprojects]

i have blown up so many electrolytics to know that the cans are not that shape so yes i would say it is deformed. (don't quote me on that though)
i hope this helps

[T3sl4co1l]

If it's regular and even, that's normal for some types; crimping the sides allows more heat transfer.  Although I've only seen it in big ones (computer grade sized).

Tim

[ataradov]

That does not look regular at all. I'd say this one is dead.

If you decide to replace it, do a teardown of this one. Never seen them implode, it usually goes the other way around

[edpalmer42]

Sometimes a plastic sleeve will ripple like that when it gets hot.  It kinda wants to shrink, but it's not heat-shrink so it gets confused.  Does that capacitor run hot?

Ed

[SeanB]

Probably was crushed by a pick and place machine during assembly, leading to the crushed sides. Probably should be removed and replaced, though it probably is still working well. Have a look at DextersLab for a teardown of one of Ian's scratch and dent large caps.

[ataradov]

Probably was crushed by a pick and place machine during assembly, leading to the crushed sides.

It actually takes a lot of force to squeeze the capacitor like that. I doubt anything in a PnP machine can get even close to the force required.

[calexanian]

Defiantly a singularity in that one. Watch out for various radiation and other charged particles. My rule of thumb on caps is if anything about them catches your eye, just go ahead and change it. They are cheap. Far more so than any amount of time worrying about them.

[Deathwish]

Yes, I had one on one of my frequency Generators I have that looks like that, i had to remove it.

[timb]

Okay, I'll replace it. As far as I can tell, it isn't running hot (I'll run it with the cover off this afternoon and see how warm that area gets; there are a bunch of diode bridges and three linear rectifiers only being cooled by the PCB board). It's run fine over the two years I've owned it (and it came brand new from Tek).

I kind of expected better QC from Fluke/Tek. Ah well, I guess I can clean the flux off the board too (in the analog section, no less, which is just shameful on a 5.5 digit meter).

Here's a few bonus pictures to show the cap in relation to other parts:








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[dr.diesel]

I have a 4020 as well, dangit, now I gotta yank it apart and see what mine looks like, LOL.

[dexters_lab]

I had to open my Tek DMM4020 to fix a broken clip inside the front panel. Looking at the main PCB, I noticed this capacitor. It appears deformed, but it's not leaking.

Is that some weird shape I've never seen before? Does it contain a miniature black hole causing it to implode (and trapping the electrons in a singularly)? Or is it a dud?

Sent from my Smartphone

Probably was crushed by a pick and place machine during assembly, leading to the crushed sides. Probably should be removed and replaced, though it probably is still working well. Have a look at DextersLab for a teardown of one of Ian's scratch and dent large caps.

The internal clearance will be much smaller on a low voltage capacitor so it could well have crushed the insides, probably best to change it

this is the 450v cap i did a teardown on:

[dom0]

Some large caps just have these six "dents". I guess they mechanically support the winding. If they're regular around the cap I'd not care, but if they look very irregular it's probably not made by the cap factory and I'd replace it.

[MagicSmoker]

I've seen this happen before when an elko overheats and the vent seals shut after releasing a little bit of the electrolyte. In any event, this is not normal.

[T3sl4co1l]

Like I said, bigger ones can be crimped around the sides for better heat transfer.  They leave quite a bit of space inside them, sometimes, I guess.

Dexters: your caps are fine.  It's a feature, not a bug.  Meanwhile, back to putting speed holes in my car...

Tim

[onlooker]

I guess the OP can better see if it is a machined shape or one caused by damage or it is just the plastic wrapper.

[timb]

I guess the OP can better see if it is a machined shape or one caused by damage or it is just the plastic wrapper.

Turns out, it was just the plastic wrapper. I guess it didn't evenly shrink or something? The plastic was so rigid that it made it look and feel like the metal was dimpled. In fact, I didn't realize until after I had unsoldered the cap (at which point I removed the plastic).

The can itself was a perfect cylinder and it tested fine, so I printed out a new label and soldered the cap back on the board.

So, that explains that.


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[printplaatreparatie.nl]

Very old topic, I know but didn't want to start a new one for my post.

I found that some new capacitors are dented as well. I remember seeing the dents on big fat caps in old industrial equipment, but found dents in my new Vishay caps.

At first I was puzzled, because the ones in stock were almost identical with no deformations. But then I noticed the different vent and checked the order. I had ordered the high vibration type, which apparently has dents. Makes sense, as the construction might be stiffened by the dents.