Cap replacement advise please..

[ziggatron]

Hi I have a Foxconn motherboard (I will post a pic if I am allowed..) I have a situation where due to the design (board was realeased in 2006/7) there is a Rubycon Electrolytic through hole 22mm 16v 1800uf MBZ T0619 capacitor that is preventing the proper fitting of a chunky graphics card, due to the card being too long and the back edge hitting the top of the rather high 22/23mm cap....

I think I have the tools and skill level to replace the cap.

Ideally I want to replace it for a shorter cap, preferably <12mm.

Firstly I wanted your wealth of opinion on the feasibility of this.

I have looked on a this website for possible replacements and even spoke with their tech adviser.

http://uk.rs-online.com/web/c/passiv...ock=4294955811

To be honest I don't think Capacitors were his strong point..

I can find caps that have the correct capacitance and voltage but I don't know what the ripple current is for the cap on the board.. so I can't be sure I am getting a comparable component.

It also appears that the substitute electrolytic caps are pretty tall also..

The other thing I was wondering was would it be possible to replace it with the higher quality conductive polymer cap which are a lot smaller typically..


Any advise would be appreciated.


Many thanks.

[mariushm]

Re: Cap replacement advise please..

Rubycon MBZ is a type of capacitor that's have very low esr and high ripple... it's unlikely you'll find something very close to its specs and especially in smaller size.

1800uF 10x23 12mOhm 2800mA ripple

Closest you'd probably get to would be Nichicon HN or HZ if you can still get them (they've discontinued recently) ... rs-online doesn't.

My suggestion would be to go down a bit in capacitance to 1500uF and then you'd be able to use something like this Panasonic FM 1500uF 16v capacitor:

http://uk.rs-online.com/web/p/alumin...itors/5261294/

At 12.5x20 it's a bit smaller, and has 18mOhm esr and 2600mA ripple which is close enough.
But I don't think 3mm difference would help much.

Polymer capacitors are mostly low voltage ... high voltage like 10v+ and high capacity are very expensive, for example rs-online has a 1000uF 16v 16x26mm sanyo polymer at around 8 pounds.

[ziggatron]

Re: Cap replacement advise please..

Thanks for the reply..

Yeah, looking through the polymer caps the highest voltages I saw was 6.4v out of 3500 caps there were two/three..

Also noticed that any replacement electrolytic cap that met the spec was gonna be big.

like you say 20mm..

So I looked for a different solution..

And found one.

Modify the cooler on the card.. By cutting a small area of plastic away there are no further obstacles fortunately and the card fits perfectly..

It was simple and effective, should have thought of that first bit obvious really..

I will post a couple of pics in the unlikely event anyone is as stupid as me and finds themselves in the same boat and didn't see the obvious.

Been reading through a few of the threads here, must admit you do seem a very helpful and knowledgeable bunch..

Very refreshing.

Thanks again.