Computer Power Supply - Salvageable?

[Keken]

Hello everyone,

I have done some research on soldering and I am excited to take it on as a hobby! Watching some of the youtube videos really got me thinking of some of the things I could repair at home. I have not started this hobby yet but I'll be starting soon when I get my soldering iron tomorrow (will be trying to fix small stuff first, like a cable).

While I was thinking about things to fix I came across my old Power Supply. I already used its "lifetime warranty" once and they wont take it back a second time.  So I decided to open it up and was hoping all I would have to replace is a capacitor. There are two bad capacitors that are visible. I think that could be an easy fix, but my other concern was this copper colored stuff that's on the image on the right:


(Ultra X3 1000Watt Power Supply)

I've been looking for videos on how to possibly clean this and salvage it, but I wasn't too satisfied with what I found so I figured I'd ask my questions here.

1) Is this salvageable?
2) What is that copper color residue on there?
3) Is that way too much solder on the back of that board? Answered! Thank you David Hess and kolonelkadat for the info!

I am a noob and do not want to work on this until I got some experience soldering and some great feedback.

My thought process was cleaning it with vinegar or lemon juice, letting it dry, de-soldering (the yellow cables), cleaning it again with alcohol(?), drying it again and re-soldering those yellow cables.

Let me know your thoughts

Thanks in advance to those who help!

-Keken

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Forgot to mention this as well, I'm not sure if the fuse is still good.

[mariush]

Use isopropyl alcohol to clean the back side. You can easily find it in shops or online (amazon for example)

What you have there may be flux or some glue... can't tell from the picture.

[Rasz]

I already used its "lifetime warranty" once and they wont take it back a second time.

are you in us or some other third world country with no consumer protection?
warranty is warranty, there is no such thing as one time warranty.

yellow stuff looks like rubber glue? it doesnt matter, no need to touch it

what is wrong with this psu? if its dead replacing caps might not be enough
not all bad caps are visibly bulged/damaged/leaking, you need to test them or just replace all in bulk

[Keken]

Thank you both for your replies.

I used the isopropyl alcohol to clean the back side of it, looks much cleaner now and got the majority of the dust off. The texture of the spot I was concerned about feels like a very thin layer of glue, I wont touch that part.

Rasz, any recommendation on a multimeter or other device to test out the caps? (<$50 would be great)

The part about the warranty, they were only able to replace it once, they stopped making this version of the psu. I got this psu over 6 years ago. Not sure if the warranty would have covered fixing the darn thing, but I had to pay for the shipping the first time and hey, maybe I can fix this on my own and probably cost less than the shipping. In any case, I'm gonna take on this challenge when I get comfortable fixing other things that I have laying around.

I've got my old GTX 295 from BFG before they stopped making video cards. I'm gonna take a look at that next.

Again, thank you both for your replies. Any and every piece of info helps.

-Keken

[Rasz]

pretty much doesnt matter, ESR meter is just a alternating voltage at ~100KHz meter, so nothing fancy
even this will be enough
http://www.ebay.com/itm/DIY-Kit-Capacitance-ESR-Inductance-Resistor-LC-Meter-Tester-NPN-PNP-Mosfet-M168-/281262386306


but its pretty niche, will be cheaper to just replace all the caps on 12V lines (I suspect those are the faulty ones?)
you still didnt say what is wrong with psu

[lowimpedance]

Also as a noob you are aware that the caps are polarized!. ie dont put them in the wrong way!!. As Rasz said, it may not be just a cap/s  that are dead. Wouldn't  it be easier in the long run just to get a new PSU.
How ever if its for education, have a go but make sure you know what your getting into.

[David Hess]

The stains look like they could have been caused by electroysis when that corner of the board got wet but I suspect the capacitors failed and leaked.  Cleaning it and replacing the capacitors will likely fix it unless the traces were dissolved.

Excess solder like that is common.  Sometimes that is done to increase the current carrying capability of the traces.

[German_EE]

On the mains side of your power supply there should be two larger capacitors. Remove these and examine them carefully because if they fail your PSU could a) stop working or b) go off with a bang.

Take care working on these units because the capacitors remain charged for a few seconds after the mains supply is disconnected. They can supply quite a 'bite'

[kolonelkadat]

3) Is that way too much solder on the back of that board?[/b]

adding solder to traces decreases resistance and increases current capacity.
dave has done a video on it

so has mike

[Keken]

if its for education, have a go

It is. PSU is one that has been laying around, don't need it, but would be great if it was working again.

The stains look like they could have been caused by electroysis when that corner of the board got wet but I suspect the capacitors failed and leaked.  Cleaning it and replacing the capacitors will likely fix it unless the traces were dissolved.

Excess solder like that is common.  Sometimes that is done to increase the current carrying capability of the traces.

Didn't know about the excess solder part. I'll be checking out the capacitors when I get a meter (hopefully today). Thanks David, I appreciate the info.

On the mains side of your power supply there should be two larger capacitors. Remove these and examine them carefully because if they fail your PSU could a) stop working or b) go off with a bang.

Take care working on these units because the capacitors remain charged for a few seconds after the mains supply is disconnected. They can supply quite a 'bite'

I hope it's not the larger capacitors. All I got here in Chicago are radio shacks and I did not see one that big there. Might have to get those online if that's the problem. Maybe the micro center here might have one.

adding solder to traces decreases resistance and increases current capacity.
dave has done a video on it

so has mike

Thanks for posting those videos for me. I guess when I take on this project, I'd probably have to put the same amount of solder back on there.

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Thank you again for your replies everyone. I'm enjoying all the info everyone is giving me. It sets me off on a path that breaks out into more paths and I can't help but move forward!

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On a side note, I got my soldering iron yesterday and tried it out on a usb cord. It works! I think I put too much solder on it though (didn't take a picture). It takes a few seconds before the phone I used (old crappy one) to notice its charging.
Anyway, thanks again!

-Keken

[Keken]

More pictures

[mariush]

I hope it's not the larger capacitors. All I got here in Chicago are radio shacks and I did not see one that big there. Might have to get those online if that's the problem. Maybe the micro center here might have one.
-Keken

Don't buy capacitors from fucking Radioshack, they're bottom of the barrel capacitors that are not suited for power supplies.

Power supplies need LOW ESR ,  HIGH RIPPLE  capacitors.

Go on digikey.com , newark.com, mouser.com ... search for Panasonic FM or Panasonic FR,  Nichicon HM, HN, HW,  United Chemi Con KZE  etc etc...  you can't just use any "made in china" capacitor from Radioshack in such a power supply.

[Keken]

lol. no radio shack, got it.

I'll look for the brands you mentioned when I start this.

Thanks

[Richard Crowley]

Switch-Mode Power Supplies (SMPS) are notoriously difficult to troubleshoot and repair.  And you will pay 10x more for whatever replacement components than the original manufacturer got them for.

Add that to the fact that PC power supplies are commodity items and are so inexpensive, I can't see how it is practical to repair this?  Am I missing something here?

[Mechatrommer]

looks like some sort of glue (we call it jebsen glue here) maybe strong solvent, thinner or what may remove it, or maybe using sharp tip knife and peel peel job. and then  melting solder of that magnitude i believe you'll need the "horse dick" iron to get thing easier. or hot air blower at max setting with patient. care to post picture of the damage capacitors? i also have many broken psu but not sure which capacitor to fix, and also supply is not so easy here. if removing and testing them all, i think buying a new psu will be easier.

[David Hess]

Switch-Mode Power Supplies (SMPS) are notoriously difficult to troubleshoot and repair.  And you will pay 10x more for whatever replacement components than the original manufacturer got them for.

The most common failures are easy to diagnose and repair.

Add that to the fact that PC power supplies are commodity items and are so inexpensive, I can't see how it is practical to repair this?  Am I missing something here?

They are not that cheap.  Good ones go for $80 or higher and most failures involve the output capacitors wearing out which amounts to $10 worth of parts and the replacements are likely better than the stock ones if you know what you are doing.

[Mechatrommer]

i figured out the good ones are due to better sleeving, painting and big fan and metals only, which are not critically needed. performance wise, its nothing difference from medium priced one (not super cheap though), sometime even better, like my currently operating $30 tronmonxter 450W psu compared to the last time and dead 2 nos of $80 500W gigabyte (crap) psus.

[Richard Crowley]

I wouldn't trust my computer to a repaired power supply that has already failed once. 
It is not a good omen for continued reliability, and it is false economy IMHO.

[Keken]

care to post picture of the damage capacitors?

These are just the visible ones I noticed, still taking my time on buying a meter to test others if need be.

[Tothwolf]

Don't buy capacitors from fucking Radioshack, they're bottom of the barrel capacitors that are not suited for power supplies.

Power supplies need LOW ESR ,  HIGH RIPPLE  capacitors.

Go on digikey.com , newark.com, mouser.com ... search for Panasonic FM or Panasonic FR,  Nichicon HM, HN, HW,  United Chemi Con KZE  etc etc...  you can't just use any "made in china" capacitor from Radioshack in such a power supply.

Nichicon HM, HN and HZ are discontinued now. They don't usually have a high enough ripple current rating for PSU use anyway but were excellent for older motherboards. Nichicon HE, HV, PW, and PM seem to be the best for these sorts of PSU applications. I wouldn't personally touch a United Chemicon with a 10ft pole, although some people swear by them.

[Tothwolf]

For a PSU such as this where they used low quality electrolytic caps, just replace them all. Replacement electrolytics are inexpensive and it isn't worth the headache of trying to troubleshoot it again if another cap fails later. I have about a dozen or so PSUs in my work-queue that I'm going to be starting on in a few weeks and replacement electrolytics for them averaged between USD $12 and $25 per PSU.

As for replacement caps, you want low ESR high ripple current rated parts for the filter caps. I prefer Nichicon HE or HV for those but when a specific value/size isn't available in those two series, I'll go for Nichicon PW or PM. For the smaller parts (generally 47uF or smaller) I'll use Nichicon PW but very occasionally (0.33uF, 0.22uF, 0.1uF) I'll use VZ. The larger two main input filter capacitors don't fail as often, but I generally replace those as well. Nichicon CS, CY, GU, and similar series tend to be suitable replacements for those. Beware though, there are a /lot/ of counterfeit electrolytics on eBay, so stick to a major vendor such as Digi-Key/Mouser/Farnell/Newark/etc.

Not only do you need to match up the value (uF) and voltage of the capacitors though, but you need to make sure the replacement has at least the same or better ripple current rating and also match up the diameter, height, and lead spacing. Capacitor manufacturers specify the physical measurements in mm in their datasheets, but beware, sometimes a particular value/voltage capacitor is made in 2 or 3 different physical size combinations. Sometimes you can substitute a smaller/larger diameter (10mm for 12mm for example) or a shorter/taller part, but for larger diameter parts (8mm or larger) try to match the lead spacing so you won't stress the solder joints. In general though, with modern PSUs made within the last 10-15 years or so, you want to avoid replacing a larger diameter part with a smaller diameter part even if the lead spacing matches because the larger diameter part will have a higher ripple current rating and be rated for longer service life.

Another tip, make a list before you order anything. I've found it easiest to go with a format similar to:

C1 1500uF 16V 10mm 25mm 5mm

Where C1 is the board designation, then value, voltage, diameter, height, and lead spacing. Making a list such as this will save you a lot of headaches. As you add each part to your list, mark the top of each capacitor with felt-tip sharpie marker too.

[Rasz]

I wouldn't trust my computer to a repaired power supply that has already failed once. 
It is not a good omen for continued reliability, and it is false economy IMHO.

yes, and I wouldnt trust my car after brakes failed and got fixed once
I wouldnt trust my airpla....

electrolytic capacitors are pretty much consumables in the age of SMPS, replace every 2-3 years if in heavy use

WTF, this is electronics forum, fixing is what we do

[Keken]

Thanks Tothwolf! That is a lot of great and helpful information. This will definitely help me out.
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I'll make sure to write everything down and post the parts I will be buying before actually buying it just to make sure I got it right. I'll take a pic of the old ones as well and post them.

[SeanB]

There very simple, if it has a green, black or brown sleeve and is a capacitor replace with new. If you cannot get the exact value go to the next higher one, and for voltage the same. Try to get the same diameter and luckily here height is not a worry, so if they are slightly higher no worry. Just stay with the brands and series mentioned, if you buy on price you will be replacing them again soon.

[David Hess]

When I do this I select the capacitors based on lead spacing and diameter first and then capacitance which may be higher.  If I can get a higher ripple current rating with a higher voltage unit which will still fit which is usually the case, then I do that as well since the increase in price is small.

There is little reason not to change all of the capacitors except for the input filtering capacitors unless their is reason to suspect them as well.  Those are usually selected based on hold up time and maximum voltage ripple so their ripple current rating is irrelevant.