bulging caps

[kleung]

Hi there guys,

Great forum, just tried recapping a functional Dell Gx745 sff motherboard (BTX motherboard and proprietary).

So... replaced 6.3V x 2200uF capacitors with new ones from Sayal Electronics here in toronto (Nichicon caps).

The computer runs fine.

HOWEVER, 2 of my new caps that I installed exhibit some mild "bulging" even before I powered up the system. I examined them all and tested them before installation with a multimeter so I knew they were at least visually good.

Are they bulging because I overheated them? Is this of significant enough concern that I should recap them again?

I used a 40watt Soldering iron to place on. Maybe should have used 40W to remove caps and 25 W to solder on.

Many thanks, I'm a newbie to motherboard recapping.

[selldoor]

Re: bulging caps

Perhaps a close up picture would assist in our assessing the extent of the damage.
Check its not just the plastic sheath bubbled.

use the manage attachments button, which is found by clicking "go advanced" under quick reply. (max resolution 2000x2000 and 2MB)

Please do not post inline and offsite as they slow down the loading of pages.

[momaka]

Re: bulging caps

Perhaps a close up picture would assist in our assessing the extent of the damage.

+1

It would also (usually does) tell us if the caps are genuine. Many places online, especially ebay, often have fakes of well-known brand caps. I'm not familiar with Sayal Electronics, so I advise you to be careful.

And even if those Nichicon caps are not fake, it's important to know their series as well. Nichicon HM, HN, and HZ are the only ones suitable series for motherboard use (for larger 470uF and above caps, that is).

[kleung]

Re: bulging caps

Many thanks for the quick replies. I have taken some pictures and included them here.

[Heihachi_73]

Re: bulging caps

AFAIK Nichicon caps don't have a K shaped vent, so they're probably fake. The K design also looks like a Sanyo type, so it's probably the same company who makes the fake Sanyos. Every Nichicon I've seen has always had a cross shaped vent (+ or x).

[Scenic]

Re: bulging caps

Those are definitely fakes.
Nichicons always have a "X" vent on top, not a "K". The color scheme is wrong too.
Nichicon HM/HN are black with white (sometimes gold?) text, not green with gold text.

You've been ripped off. If you bought them on ebay, leave negative feedback.

edit: oh and that's more than just a "mild bulge". These have already failed without even being used. Should tell you something about the "quality" of those caps..

[kleung]

Re: bulging caps

thanks for the quick reply and analysis.

The good news is the system is working. It is disheartening to have re-capped the motherboard and having to do it again some time soon.

Sayal electronics is a big enthusiast electronics parts/components store here in Toronto.

Badcaps.net is obviously the place to go for genuine stuff but I was impatient and for 5 caps; they had them locally for $3.50 which is less than shipping.

Oh well, this post can confirm that as of 2012 June, Sayal electronics still is selling fake caps (as per forum member analysis/opinions).

[momaka]

Re: bulging caps

Better recap it again very soon before they take out a MOSFET or leak electrolyte on the motherboard.

[selldoor]

Re: bulging caps

Perhaps you should go see what Sayel say and ask for your money back.
Perhaps they just got the order wrong?
If not totally happy with the outcome report them to local inspectorate.

[kleung]

Re: bulging caps

I will ask them about it with the member's evaluation here.

I am not sure if they will do anything about it.

I'll recap it when I can.

The thing is, Sayal isn't some fly by night store; they are actually one of the few big retailers for electronics components in Toronto with multiple retail sites.

http://sayal.com/zinc/zinc_about.asp

[kleung]

Re: bulging caps

Also,

I agree that the capacitors are probably fake.

HOWEVER, Could I have damaged them during the installation by overheating them with the soldering iron?

Not sure why just 2 of them would have failed during install otherwise? Can I damage good / authentic capacitors during installation that way as well?

[mariushm]

Re: bulging caps

No, it's very unlikely you damaged them from the soldering.

[retiredcaps]

Re: bulging caps

I am not sure if they will do anything about it.

The thing is, Sayal isn't some fly by night store;

If they are a reputable store and want to keep it that way, they will investigate. They would want to know that they are selling counterfeit goods.

[momaka]

Re: bulging caps

No, it's very unlikely you damaged them from the soldering.

I agree.

In my experience, it takes A LOT of heat to kill good caps. I know because at the place where I work at, we regularly reflow Xbox 360 consoles and when we do that, the caps often heat up to 100+C on the machine. So far, all of them have been fine as long as the heat doesn't go much higher than that. If the board is left on the machine for very long, only then the caps would start to bulge - that's usually 10+ minutes where the whole board is at 220-230C (so the caps are probably no less than 150C).

In any case, I very much doubt your caps could have reached that temperature by just heating them with a soldering iron. More than likely, they bulged because they are cheap fakes.

[ratdude747]

Re: bulging caps

They are obvious fakes, thats the sole reason they died. a soldering iron (even a good one) can't bulge a cap unless you intentionally try to... as in keeping the iron on the joint for hours and hours.

Get some real caps at the badcaps.net store and redo the recap. Every cap you installed needs to go, even if it hasn't bulged. Fake caps only belong in one place, and that's the "never buy" list.

[tom66]

Re: bulging caps

Is that a fake Nichicon with a Panasonic "T" vent?

[c_hegge]

Re: bulging caps

Fake caps only belong in one place, and that's the "never buy" list.

They also belong in fires and on test benches where they can be over-volted

[tom66]

Re: bulging caps

Just beware some of these cheap caps have really dodgy safety vents. They will vent but only at the last moment. I have had one nearly go bang on me because the vent was very tight.

[Jooo]

Re: bulging caps

They look quite like these. http://m.dealextreme.com/p/16v-2200u...ece-pack-91279

[larrymoencurly]

Re: bulging caps

AFAIK Nichicon caps don't have a K shaped vent, so they're probably fake. The K design also looks like a Sanyo type, so it's probably the same company who makes the fake Sanyos. Every Nichicon I've seen has always had a cross shaped vent (+ or x).

Could reverse polarity have made the caps bulge so soon? What if the counterfeiter was faking Sanyos and Nichicons and was so careless they not only got the shrink wrap mixed up between those brands but also installed it rotated 180 degrees wrong?

I'd look for a more reputable counterfeiter.

Are there any cap counterfeiters that buy rejects of Japanese brands and then repackage them? A janitor at a local Intel factory used to steal rejected CPUs, and reportedly the ones with cosmetic flaws (even crooked markings) turned out to be pretty good.