Recapping A Board With Different Capicitance Caps?

[opaque]

Hi, I've recapped a couple of boards successfully before, but this MSI 694D Pro2 board I've had for 4 years 24/7 has developed bulging caps and the local store that sells Rubycon / Sanyo Organic caps doesn't sell exactly the ones i need.

Is it safe to replace capacitors with a higher capacitance? I understand the voltage must be exactly the same right? e.g. I need 1000uF 6.3V caps, can I replace those with 3300uF?

The shopkeeper says I can replace my 2700uF 6.3V capacitors with 3300uF 6.3V and it'll be fine. I'm a bit skeptical and would like some feedback.

'Thanks!

[bushytails]

Re: Recapping A Board With Different Capicitance Caps?

Bigger is better.

Neither higher voltage nor higher capacitance is going to cause problems.

--Randy

[opaque]

Re: Recapping A Board With Different Capicitance Caps?

Cool! Just checking... Thanks! I'll get 470uF's for the 330uF's etc,.

[kc8adu]

Re: Recapping A Board With Different Capicitance Caps?

should be fine.
my 694d's have 3300@6.3 in place of the 2700 with no problems.

[Chris1992]

Re: Recapping A Board With Different Capicitance Caps?

In reply to: "I need 1000uF 6.3V caps, can I replace those with 3300uF?" replacing 1000uF with 3300uF is a drastic jump, tripling the capacitance. I'd replace them with 1500uF. It's generally not really a good idea to replace caps with >150% the original value.

<offtopic>This is the board's 4000th Post!!!</offtopic>

[bushytails]

Re: Recapping A Board With Different Capicitance Caps?

I think all the 1000s are just filter caps on the 3.3v or 5v lines... you could put capacitors on them half the size of the motherboard and it wouldn't hurt anything.

I've replaced many with vastly-huger (3x the capacitance) caps with no problems.

--Randy

[opaque]

Re: Recapping A Board With Different Capicitance Caps?

In reply to: "I need 1000uF 6.3V caps, can I replace those with 3300uF?" replacing 1000uF with 3300uF is a drastic jump, tripling the capacitance. I'd replace them with 1500uF. It's generally not really a good idea to replace caps with >150% the original value.

Heh, that was just an example... I'm replacing the 2700uF, 6.3V's with 3300uFs, 1500UFs with 2200uFs, and 330uF 16V with 470uF 16V.

Those are the closest upwards the store sells - and very cheap too... HK$20 for 10 on most (that's about US$3 for 10)

[AK0R]

Re: Recapping A Board With Different Capicitance Caps?

Heh, that was just an example... I'm replacing the 2700uF, 6.3V's with 3300uFs, 1500UFs with 2200uFs, and 330uF 16V with 470uF 16V.

Those are the closest upwards the store sells - and very cheap too... HK$20 for 10 on most (that's about US$3 for 10)

What manufacturer and series are you using? I don't believe anyone here has been able to find quality parts for anywhere close to those prices. You need to make sure you're using high-quality, low-ESR capacitors, or the board will be unstable at best, if it boots at all. Then you'll find yourself in the midst of a massive troubleshooting effort, and end up having to recap again, or else give up and pitch the board. Better to spend a little more and get the right parts the first time.

[Chris1992]

Re: Recapping A Board With Different Capicitance Caps?

in his first post he says ‘Rubycon/Sanyo Organic'. And those replacement values are ok.

[opaque]

Re: Recapping A Board With Different Capicitance Caps?

What manufacturer and series are you using? I don't believe anyone here has been able to find quality parts for anywhere close to those prices. You need to make sure you're using high-quality, low-ESR capacitors, or the board will be unstable at best, if it boots at all. Then you'll find yourself in the midst of a massive troubleshooting effort, and end up having to recap again, or else give up and pitch the board. Better to spend a little more and get the right parts the first time.

That's the beauty of living between Hong Kong and Canada ... I'm using the Rubycon MCZ series (again, I used them before with a different MSI board too) and for the 100uF 10V one they didn't have Rubycon in stock so I'm using the Sanyo organic or wahtever it's called.

If you buy in bulk, you can get 10 pcs for $19-25 HK (about US$3-3.50). I know the shop is not selling fakes because they're very reputable (especially when it comes to selling Silverstone and Zalman stuff).

[RJARRRPCGP]

Re: Recapping A Board With Different Capicitance Caps?

I was given a Shuttle AK31 motherboard that won't even POST, no video and no bleeps at all!!! Thus, I'm thinking about recapping it, because of the possibility that the caps are bad when not visibly bad. The motherboard currently just won't POST. Because a damaged processor can cause the same symptom, I checked to see if the processor that was in that motherboard was still good and it's at least alive.

I'm thinking about recapping it, because the brands of the caps are on your blacklist, even when a couple of my other motherboards have caps from one of the companies in the blacklist, I still have yet to see signs of them going bad. The motherboard has OST (also says IQ on them?) and G-Luxon caps.

Also, a major update, Radio Shack apparently is selling Nichicon caps!
But, they weren't the models that were known to fail, definitely wasn't HM (N) nor HM (M). It looked like one of them said PL (something). But, I hope they're low ESR!!! Because if they are, then I may come back there to get stuff for doing an experimental motherboard recap!

[bushytails]

Re: Recapping A Board With Different Capicitance Caps?

I use PW, PM, and PL nichicons with no problems... they're heavy-duty caps meant for switching power supplies, with low ESR. the problem is they're often much larger (physical size) than the panasonics or other replacements.

--Randy

[MD Willington]

Re: Recapping A Board With Different Capicitance Caps?

We use PW, PM, and PL Nichicons with no problems...either, we've HALT tested them typically at 90°C for 90+ days without any ill affect.

...no ones computer is going to run like that...

The equipment it goes into has a 10 year warranty, given that we do not expect any capacitor to last that long...the main product with those capacitors has a calculated MTBF of ~5000 years.

...again we we do not expect any capacitor to last that long...but these Nichicons are known to us to be quality capacitors.

MD

[bushytails]

Re: Recapping A Board With Different Capicitance Caps?

I have some 5v 20amp switching power supplies intended for use in hospital equipment (unlike most that say "not for use in life support equipment", these are meant for it... and have a price tag to match!) 500,000 hour MTBF. all nichicon P* caps.

--Randy

[pawn]

Re: Recapping A Board With Different Capicitance Caps?

sorry i seldom read....jus wondering..i got all this idea that u can't replace the capacitance,but only change the voltage rating.....eg....4700 uf/6.3 v with a 4700uf/16 v....i jus want to hear some affirmations or reactions bad is good

[PeteS in CA]

Re: Recapping A Board With Different Capicitance Caps?

The three big considerations here are the capacitance, the voltage rating, and the impedance (impedance incorporates ESR and ESL).

If you are dealing with the output caps of the VRMs, they can affect the stability of the VRM's control loop. I'd recommend against going higher than 150% of the original values.

Wrt voltage ratings, if a 10V part is used on a 3.3V or 1.8V output (O/P), using a 6.3V part should be safe. The MB mfr probably did that to reduce the number of different parts they use - economies of scale. While using higher voltage parts will be safe wrt voltage, you need to be careful not to use a higher impedance part. A higher impedance part may not last as long as it should.

The impedance (Z) is critical. The power dissipated by the cap (power means heat) is I(Ripple)^2 * Z. The higher the Z, the hotter the part.

With Nichicon, PLs and PMs are the same basic parts, except the PM is lead free. The PWs are a newer series, with (usually) higher capacitance and lower Z in a given can size and voltage rating. Nichicon parts whose series names begin with "H" (e.g. HE, HC, HD, HM, HN) are a different electrolyte technology, and usually have significantly lower Z than P* series parts. I would recommend against substituting PW for HN or HM.

[Harvey]

Re: Recapping A Board With Different Capicitance Caps?

Likewise with the 150% over stated capacitance maximum for replacement, don't go too far above the rated voltage too. Electrolytics work by using the voltage flowing through to form (and repair) a layer of oxide, if there's insufficient voltage flowing that process can fail.

I don't think there are any actual rules, and I've never seen any published figures (never actually looked to be honest), but I was told to ensure a capacitor has around a third of its rated voltage as a minimum.

i.e. don't replace a capacitor that has 5V on it with one rated at 50V or something equally extreme, even if it will fit, as its not likely to last long; using something like a 10V or 16V would be OK though.

[Logistics]

Re: Recapping A Board With Different Capicitance Caps?

ensure a capacitor has around a third of its rated voltage as a minimum.

i.e. don't replace a capacitor that has 5V on it with one rated at 50V or something equally extreme, even if it will fit, as its not likely to last long; using something like a 10V or 16V would be OK though.

Is this strictly an electrolytic thing?

[Tom41]

Re: Recapping A Board With Different Capicitance Caps?

The way I see it, the capacitance and the voltage have to be exact if you want the best performance. I've never done a recap though, so can't be sure...

Think of it this way. Imagine you have a rechargeable battery that gets fully charged in 3 hours. When it runs out, you charge it for only 2 hours. If you keep doing that, you're not using the full potential of the battery and life can be shortened.
I assume a similar thing happens with capacitors - they're essentially very small rechargeable batteries. Someone correct me if I'm wrong!

[gonzo0815]

Re: Recapping A Board With Different Capicitance Caps?

A capacitor will not degrade if voltage or size ist higher than the operation voltage. It is a completely different story than batteries.
Shure, the oxide layer will thin out, but this will only last until a higher voltage is aplied.
The endurance is not affected by this.

Even most batteries are not dying from memory effect rathern than bad (read cheap & unregulated) charging devices or poor quality right from the start.