Replacing capacitors on a motherboard

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Hinokagutsuchi

Limp Gawd
Joined
Jul 8, 2003
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371
Unfortunately, my brother's motherboard died the other day. I counted about ten capacitors with leaks. Well the problem itself has been resolved, and I've got a motherboard on my hands. Has anyone had any luck replacing capacitors? I have seen people move them with relatively little trouble.

I'm going to go out on a limb and guess that I probably won't be able to get the capacitors at Radio Shack and that I'll have to go to a site like McMaster or Jameco to get them.

Share your stories of success or failure as well, if you like.
 
Oh plenty of luck on my video card...

I heated the bottom and just slowly pulled it out. In the end I think I used the point of the iron to just poke the rest of the cap out of the via. I presume if you wanted to do it correctly you could use a desoldering pump or braid but there really isn't much to desolder.
 
PM RavenatNM here on the forums. He's a buddy of mine that replaced some capacitors on his wife's motherboard about a year ago with great success!

Just do a search by username, and then you can click on his member info.
 
I've done it dozens of times. I usually alternate heating leads and wiggle it out. A good guesstimate for size would be 1000uF at 16 or 25 volts. It usually doesn't hurt to use a bigger cap than original. I would look at surplus dealers like electronic goldmine, All Electronics, or MPJA. Try not to buy ones that are bigger in diameter - you may have a hard time fitting them into narrow spaces. Here are a few examples:

http://www.goldmine-elec-products.com/prodinfo.asp?number=G14306
http://www.goldmine-elec-products.com/prodinfo.asp?number=G13652A
http://www.goldmine-elec-products.com/prodinfo.asp?number=G8707
http://www.goldmine-elec-products.com/prodinfo.asp?number=G9110
http://www.allelectronics.com/matrix/Radial_Electrolytic_Cap.html
 
It's better to get capacitors with the same capacitance (1000uF or whatever) as the originals. Also, the voltage rating should be equal or higher than the original. Other than that, you'll be good to go.
 
Mohonri said:
It's better to get capacitors with the same capacitance (1000uF or whatever) as the originals. Also, the voltage rating should be equal or higher than the original. Other than that, you'll be good to go.
Click to expand...

Yeah, try to match if you can, but since most are smoothing caps and not meant for timing, going a little bigger shouldn't hurt. Plus, electrolytics usually have a +/- 10 to 20% tolerance (usually minus from my experience), so going a bit bigger, especially with a low ESR cap, shouldn't hurt. Going higher in voltage gives more security, but it costs more and makes the cap physically bigger and that might preclude it fitting into the allotted space.
 
Well I made the final tally for what I need:
2200uF @ 10v: 6 + 2 spares: 8
1500uF @ 6.3v: 3 + 2 spare: 5
1000uF @ 6.3v: 8 + 2 spare: 10
23 capacitors total.

Most aren't leaking, though, just bulging. I've been able to find capacitors that match these, for the most part. They're only slightly larger, but it shouldn't pose a problem. The only trouble I have had is that I can't find any 1500uF capacitors. Would it be alright to replace them with 1200uF? I have found a source that looks like you can, but I would like a little more reassurance.
 
It's probably better to err on the side of larger caps. If you can find the same capacitance, that's best. You definitely don't want to go lower.
 
I'm just going to play devil's advocate here and throw in some thoughts to consider.

You mention that the mobo died, and observe leaky & bulging caps. The probablility is high that the caps are the root cause of the failure, but often times with power supply circuits related components are damaged or stressed as well, most likely power mosfets or transistors, maybe regulators. Unless you are able to confirm the failure is limited to the caps, you are basically risking the investment of 23 caps, shipping/handling and labor time...Unless this is a high-end expensive board, you might consider the financial comparisons of just purchasing a new warrantied board. It's unfortunate but true that most repairs are not cost effective in today's throw-away world.

Don't want to completely discourage you, and I wish you the best, but just wanted to point that out.

[edit]

If the suspect parts were limited to just a couple it would be more in your favor.
 
agent420 said:
You mention that the mobo died, and observe leaky & bulging caps. The probablility is high that the caps are the root cause of the failure, but often times with power supply circuits related components are damaged or stressed as well, most likely power mosfets or transistors, maybe regulators.
Click to expand...

Actually, it probably is the caps. Mobos from a few years ago suffered what became known as "bad cap disease". What happened is that someone stole a formula for a new electrolyte in Japan. This was then sold to various Chinese and Taiwanese capacitor manufacturers. Unfortunately, this electrolyte tended to break down and not last for more than a year or two. Its breakdown was exacerbated by the high temperatures and deep cycling of computers. It isn't know if it was an experimental formula that didn't pan out or if it was intentionally leaked to give a bad reputation to the less scrupulous capacitor manufacturers, but what is known is that a large number of electronic devices, especially motherboards, have been affected. It's no longer an issue because the electrolyte is no longer used, but older motherboards are well known for this problem.
 
Mohonri said:
It's better to get capacitors with the same capacitance (1000uF or whatever) as the originals. Also, the voltage rating should be equal or higher than the original. Other than that, you'll be good to go.
Click to expand...
Use the same voltage rating. Higher voltage capacitors typically have higher ESR, causing greater heating inside the capacitors (which have a lot of ripple current) and this can cause a quick failure.

And you want the ESR to be in the same ballpark - eg if you're ordering capacitors from Digi-Key, use the Panasonic FM series caps, not the M series which can only handle a fraction of the ripple current.
 
Fenris_Ulf said:
Actually, it probably is the caps
<snip>.
Click to expand...
Yes, I'm aware of the electrolyte issue, I guess my point was more along the lines of the cap failure killing other components. When they go, they could short, frying the switching drivers and such.
 
agent420 said:
I'm just going to play devil's advocate here and throw in some thoughts to consider.

You mention that the mobo died, and observe leaky & bulging caps. The probablility is high that the caps are the root cause of the failure, but often times with power supply circuits related components are damaged or stressed as well, most likely power mosfets or transistors, maybe regulators. Unless you are able to confirm the failure is limited to the caps, you are basically risking the investment of 23 caps, shipping/handling and labor time...Unless this is a high-end expensive board, you might consider the financial comparisons of just purchasing a new warrantied board. It's unfortunate but true that most repairs are not cost effective in today's throw-away world.

Don't want to completely discourage you, and I wish you the best, but just wanted to point that out.

[edit]

If the suspect parts were limited to just a couple it would be more in your favor.
Click to expand...

I see your point, but it's going to be around $5 to buy the caps. The investment isn't that big, and the labor time will help me kill the boredom that's been plaguing me. If it's still fried, oh well.

I guess since I'm having trouble finding 1500uF, I should go with something higher, then, like a 2000uF, right?
 
2200 uF should be fine, just make sure the overall size and lead spacing are close.
 
Hinokagutsuchi said:
I see your point, but it's going to be around $5 to buy the caps.
Click to expand...
I see... That's a good deal then. I recently recapped an old oscope and quality caps averaged $2 or more each at Digikey.
 
agent420 said:
I see... That's a good deal then. I recently recapped an old oscope and quality caps averaged $2 or more each at Digikey.
Click to expand...
http://www.badcaps.net/kits/

They charge $1.10 each for Rubycon capacitors... and they sell kits for common 'bad cap' motherboards.
 
it is definatly possible to save it by just soldering on new caps... i'd say go for it... it's not hard to replace caps...
 
It looks by now you probably found the caps... and they are going to cost you $40-50 by the time you get done with tax and shipping and handling. You might want to look into what it would cost to replace the whole MOBO with one that will work with your CPU, memory, and video card.
 
Fenris_Ulf said:
It's no longer an issue because the electrolyte is no longer used, but older motherboards are well known for this problem.
Click to expand...
I'm not so sure the problem is over. I looked inside my 6-month-old router the other week and found the smoothing cap, a 1000uF 16V 105C, badly swollen and leaking at the vent. The brand, CTC, is listed at badcaps. There's also a swapping how-to on the site.
 
Mohonri said:
It's probably better to err on the side of larger caps. If you can find the same capacitance, that's best. You definitely don't want to go lower.
Click to expand...


not nessearily. it depends on the system.. bigger caps = slower response... so it depends on what the function of these caps are...

it probably isn't a problem though to go a bit bigger...
 
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