Replacing Caps

[Lord AnthraX]

I recently had a motherboard pop 5 capacitors and I was wondering if it would be worth it to try and replace them or just buy a new mobo. The mobo in question is an old Socket 423 VIA something or other. It's one of the best one's i've seen but again, not the point. The caps in question are the main caps next to the CPU, so I have no idea if it would be possible/advisable to try and solder new ones in. Anyone that's done it/knows how to do it please do give some advice.

[Crashman]

Remember when bad capacitors made a big "bang" in the electronics media a couple years ago? I was the guy who "blew" the whistle. Someone else was repairing boards already, but not well publicised, I was contacted by a guy from electronic news after posting a few things at another site. Having been in the motherboard repair industry, it's easy for me to say that repairing your board is probably one of the easiest solder jobs you'll do.

Simple really, you just heat one leg and tip the capacitor one way, then do the same to the other side, until you've walked it out of the hole. The easiest way to put a new one in is to make sure the hole is still at least mostly filled with solder. Then you can heat the spot where the leg comes through and walk the new one back in, through the pool of solder.

Quality capacitors are very expensive unless you buy them in huge quantities. Because of this, I keep a large stock of used caps pulled from otherwise worthless older boards. Since high quality capacitors last very many years, it's OK to use used parts.

One problem you may have is that many boards made with cheap parts (such as VIA chipsets) have undersized caps packed so closely together that standard sized caps won't work. Often that means 8mm caps where it's hard to find replacements smaller than 10mm, or 10mm caps where it's hard to find replacements smaller than 13mm.

If you can't find an exact replacement, go with the next voltage up. For example, if you have 6.3v 1200uf caps, it's OK to go with 10v 1200uf. In some ways it's actually better, because the higher voltage tolerance will enable it to tolerate larger spikes.

So replacing the caps is easy, finding the right ones (especially at a decent price) is the hardest part, and if all else fails in your search, start looking for donor parts on other boards.

[Crashman]

Oh, I almost forgot, pay attention to the stripe on the capacitors, it marks polarity. Make sure the new one goes in the same orientation as the old one.

[Lord AnthraX]

Ok then, I relized it might have been easy but not that easy. You're right about VIA using crappy parts; about the size of a dime and only about 6 of them, but it did last for a good 4 years so I don't complain, it cost me 34$. Do you think radio shack might sell capacitors for a decent price?

P.S. I have done much wiring throughout my life, but I am not sure if I can put higher power caps in or not, meaning VERY high power.

[causticVapor]

You can probably place caps with the same farad/voltage rating and have the motherboard last till end-of-life. Don't put in much more powerful caps unless you want to seriously overclock the CPU.

[Lord AnthraX]

Originally posted by causticVapor
You can probably place caps with the same farad/voltage rating and have the motherboard last till end-of-life. Don't put in much more powerful caps unless you want to seriously overclock the CPU.

Ooooo you just gave me an amazing idea which I will now try to do without creating some sort of crazy electrical fire.

[Crashman]

Last I checked Radio Shack only carried 25v and 75v caps or something like that. They also carry variety packs which might have 1 or 2 of the caps you need. You can also check places like Mouser Electronics (expensive for small quantities) or Parts Express (usually cheaper but they often don't have what you need).