# replacing power supply capacitor



## Bonzoso (Sep 15, 2011)

Hi all,

My power supply on my dell OptiPlex went kaput and I took it apart to look at the capacitors. I found one that is bulging and want to replace it. Problem is, it and a lot of the other components are covered with this white gooey like caulk which I am assuming is to dampen vibrations and such. How do I get this stuff away from the capacitor I want to remove? It's all a very tight fit in this ps. Thanks for any help.


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## GrayHair (Apr 9, 2015)

Bulging electrolytics are a bad sign. If the cap has vented, that "white gunk" could be electrolyte and if it has gotten on any boards, it's wise to clean it off. The other caps are the same age and are probably due for replacement as well. After all, a stable output to the computer is what you are after.

Now I'm from the "anyone can replace, but it takes a craftsman to repair" school of thought, but considering the cost of a power supply, I'd just replace it. After replacing, you can go through the old one and decide if you want to repair it.

Personally, I wouldn't put a repaired power supply in a computer. If there's a problem, the result could be disastrous. As a project or bench power supply, I would use repaired in a minute (at first I wrote "in a flash", but decided that's not a good phrase when talking about power). *NOTE:* Some power supplies need to see a "load" before they will power up. Google “testing computer power supply”.

I'm in the process of recapping a 45 year old guitar amp that gives me a lot more room than you'll have, and it's still a pain. However, most of my pain is finding today's equivalent caps.


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## mako1 (Jan 7, 2014)

Agree with Gray hair on this one.I have built many custom electronic components over the years .Mostly custom amplifiers ,not computer power supplies but caps ar caps and electronics are the same in general.
Just replace the power supply.They can be had for relatively cheap price.
You would probably have to order the caps and pay shipping,clean up the old mess,solder in the new and unless you are experienced and have the ability to troubleshoot ,may have to buy a new power supply after you get done with it.
go to www.newegg.com and buy a new one for way less than your trouble.If you have to ask these questions on a forum you probably do not have the experience to fix it correctly.


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## Bonzoso (Sep 15, 2011)

Thanks for the input greyhair. The white gunk as I said is probably a dampening material to keep components from vibrating loose in the presence of the large fan that is squeezed into this ps. It is clearly not coming from the caps and is also all over other components. I've got some experience in amps and such from back in the 70's and 80's but this is my first time inside a computer ps. My reading on the internet kind of explains the goo but I haven't heard from any of the computer guys as to how they deal with getting this crap off the components when they want to do repairs. As for a new ps, not worth it in my book. Cost is upward of $70 vs a couple bucks for new caps and computer is almost 8 yrs old. Who knows what or when something else will go and I'd rather keep patching until I can't patch no more. I do get satisfaction out of fixing stuff and not paying out more big bucks to "the man".


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## mako1 (Jan 7, 2014)

I understand your point.The gray gunk is nothing more than a silicone base substance like caulk to keep the components where they should be .all you can do is peel or scrape it off .No easy solution .these components are not made to be worked on these days.Just replaced.
I have worked on many of them over the years and see your point .They just don't make anything simple to work on because they don't want you to.That's why I stick with vintage amps and love them.
Computer components are simply not made to be worked on but swapped out.That's how you can buy a whole new computer for $400.


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## Bonzoso (Sep 15, 2011)

Thanks for the post mako. Yeah. I guess I'll just start digging at it. To be honest I do think it's more of a way of discouraging folks, whether they are knowledgeable or not, from fixing these components themselves for a pittance compared with buying new. Way of the world now. Unfortunately not everyone has the means to go out and buy new every time some piece of Chinese crap goes kaput. I'll keep buckin' the system as long as I can get away with it. Thanks again.


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## mako1 (Jan 7, 2014)

Be aware that electrolytic capacitors will hold a charge for long after they are unplugged unless they have a bleed resistor wired to them.


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## Bonzoso (Sep 15, 2011)

mako1 said:


> Be aware that electrolytic capacitors will hold a charge for long after they are unplugged unless they have a bleed resistor wired to them.


 As I indicated, in previous posts, I'm not a newbie. Thanks anyway


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## del schisler (Aug 22, 2010)

Bonzoso said:


> As I indicated, in previous posts, I'm not a newbie. Thanks anyway


the output is 5 volt ? no charge in cap here, the other is 110 volt input no cap's here, of course unplug it, i been in repair for 50 yrs , just replace the cap's , their are plus and minus here so watch when you take them out. 1 at a time , probly only one that has a bulge on it, do you have a meter ?? ohm scale ? you can measure the 5 volt with meter set to volt scale , now their are regulator transistors in their to get the voltage to 5 volt and stay at that voltage , un-less you can measure this i wouldn't do a repair , if the voltage isn't right their goes the comp. it can't take more than 5 volt's going to the unit , good luck


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## Bonzoso (Sep 15, 2011)

Bonzoso said:


> Hi all,
> 
> My power supply on my dell OptiPlex went kaput and I took it apart to look at the capacitors. I found one that is bulging and want to replace it. Problem is, it and a lot of the other components are covered with this white gooey like caulk which I am assuming is to dampen vibrations and such. How do I get this stuff away from the capacitor I want to remove? It's all a very tight fit in this ps. Thanks for any help.


So just to close this question, and to help any other DIYers that think the scary "no user serviceable parts inside" label is gospel, I include this follow up. A sharp exacto knife and tweezers allowed me to slowly manipulate my way at freeing the offending capacitor AFTER fully de-energizing all the capacitors on the ps. I was then able to de-solder the connections at the board and remove the capacitor. I found a similar sized 10V 2200 microfarad capacitor at my local RadioShack and soldered it into place. Everything went together (I did not re-goo the cap into place) and the ps is working like a charm. $1.57 for the cap and some of my time. 

Bottom line is if you know your way around electronics there is no reason to buy a whole new part all the time. Especially when the parts are overpriced Chinese made junk that are built to fail. That goo was primarily put there probably to discourage "user servicing". Look, if it is under warranty, make them replace it, but if not, what have you got to loose. I don't know about you all, but I've got a real problem with big companies trying to force me to shell out big money to replace their inferiorly built products. If you paid attention in your science classes ( which most Americans fail to do any more) you should know enough about electronics to be aware of the dangers involved and work safely in that environment. It is not quantum physics we are dealing with here. Electronics techs come from all walks of life and if you read and study the material, you can work safely. All these "deadly warnings" are merely to cover these company's legal rear ends and to discourage you, the consumer, from saving money by doing it yourself.
Call me another satisfied DIYer.


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