Power Supply Caps Bad - What's the Cause?

[Hypnoglitz]

Hi Everyone- Opened up my network streamer tonight to just look around and discovered that 8 capacitors on the power supply board are bad....leaked everywhere. I'm capable of replacing them but am curious if there is a greater problem with the unit. The device is maybe 4-5 years old. Seems a little early for those to go bad but I'm a novice with this stuff and would appreciate any input.
Thanks.

 

[woody]

Sometimes a bad lot of caps gets produced. About 12 years ago I had a 3 year old Dell computer with a bunch of bad caps. I did a google on this and found something about Dell geting a huge batch of caps that were failing early. Oh not bad enough to force a recall
just be a pain in the *** for customers with out of warranty dead boards.

 

[PRR]

> leaked everywhere. ... I'm a novice with this stuff

Don't confuse "leakage" with the "goo" often used to glue-down large parts so they survive shipping.

(Some goo causes trouble too, but most is fine.)

 

[rayma]

Stuff like that gets the cheapest caps they can buy at the time.
If it lasts for the warranty period, that's all they care about.
But yes, be sure they're bad, and post a photo.

 

[Hypnoglitz]

Thanks for the responses!

I'm having a tough time getting a decent picture. But the caps I'm referring to are in the foreground. I don't think it's glue as none of the other caps in the unit show any sign of this substance. Almost looks like someone spilled a coke on the these sections.

If this is actually bad capacitor, it's sort of a revelation to me, as several months ago I had trouble with the noise floor in my system. I communicated several times with the maker of the unit, because I thought I had a ground issue. I never fully resolved the issue, just wrote it off as something to live with. Now having seen this, perhaps this is the culprit. I ordered $6 bucks of replacements last night, and I'm gonna do the replacement.

 

[rayma]

Be static safe, work on a metal surface, or an antistatic mat if you have one.
Avoid touching any semiconductors, and watch for capacitor polarity.

 

[Hypnoglitz]

Messed up my previous attachment.

 

[ej25awd]

Glue!

If it ain’t broken don’t fix it, I’m referring to the “leaky” caps. The Rubycon caps are probably OK, the problem is likely somewhere else.

 

[adason]

caps are ok, they usually bulge before they leak
do not touch it

 

[Hypnoglitz]

Aha...I'll leave them be, then.

Why would the manufacturer glue just a handful of caps and not the rest? There are several other caps on the power supply board that have nothing on them. Are there critical caps for a component that require extra TLC?

Thanks again for all the input!

 

[powerflux]

If it's Rubycon, they're probably fine. But the photo is not in focus.
If it's Rukycon (yes, really!) they're cheap, bad quality knock-offs.

However, 4-5 years can wear out even good capacitors in a badly ventilated design.

 

[Sorento]

Aha...I'll leave them be, then.

Why would the manufacturer glue just a handful of caps and not the rest? !

Only the heavier / bigger ones need to be fixed such that they can't move after pick-and-place and during soldering. This is all done by machines, not by hand.
Also the glue protects the heavier parts from breaking loose - rough handling while shipped or by the customer. Solder joints could break under harsh acceleration ...

 

[Hypnoglitz]

Good to know. Makes since. That explains the haphazard appearance, as well.

 

[deadpool]

Rumor in the industry was some Chinese manufacturers had problems with the electrolyte formulations so lots of electronics from about a decade ago were affected

 

[simon7000]

From the picture looks like glue.

 

[29285]

Global warming speeds up drying out

 

[JMFahey]

The ones close to board edge are easy and all got glue, some inductors also, as well as a couple midboard, but I also see 3 or 4 long skinny ones *tilted* at random angles (definitely not pushed against PCB before soldering) as well as a similar condition inductor, there may be more: those also *need* some glue around or they´ll be the first to crack their legs.

 

[sgrossklass]

Brown fixing glue - let's hope it's not the nasty stuff that turns dark brown to black and corrosive over time and has to be scraped off to avoid further damage. Normally you'd expect white goop (celastic) there.

 

[Mark Tillotson]

The glue is for vibration control, only the heavier caps need it. Heavy caps will fatigue their own leads if not mounted solidly and subject to vibration (from a fan for instance).