Replacement caps question

[aaronmarsh632]

Hi,

I'm replacing some caps on a pc motherboard. I have done so mannnyyy times before but just wanted to ask how important is it to use the exact same size caps as te originals, until now I replace the same spec and size but just wondered if it matters too much. Also can I replace bad caps with the newer solid state type aslong as the specs are the same?

Thanks

[ratdude747]

Re: Replacement caps question

Moved out of FAQ.

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Size wise: generally, if it fits, it's fine. Different can sizes will have slightly different ESRs but TBH it's not enough to write home about.

Poly caps: Depends on the location of the cap. If it's in the VRM, match the ESR. Otherwise, match the capacitance. There's threads on this already (it's called poly modding, look for that). Even ones with known configurations for boards people have already modded.

[aaronmarsh632]

Re: Replacement caps question

Hi,

Thanks for the information, i'll check out the poly modding.

[Pentium4]

Re: Replacement caps question

I think it's more important to match ripple rating than capacitance

[ben7]

Re: Replacement caps question

When replacing with new electrolytics, find the all-around best match. (Closest ESR, capacitance, and ripple current)

With poly-modding, match the ESR and the ripple current as close as possible. Sometimes you will end up using fewer polymer capacitors than you would with electrolytics, because polymer capacitors offer much better ESR and ripple current specs.

Of course, if you cant match the voltage, go higher.