[colug-432] Motherboard w/bulged capacitors

[Larry Howell]

Angelo McComis wrote:
> On Tue, Oct 13, 2009 at 2:09 PM, Larry Howell <lhowell at speakeasy.net> wrote:
>> I could take it for Free Geek Columbus and even provide a receipt for
>> tax purposes.  I'd have no problem replacing the bad caps, since I
>> salvage caps from motherboards in our recycle bin.  Please email me with
>> pickup details.
>>
>> Thanks,
>>
>> Larry
> 
> Larry-
> 
> How is your success rate with swapped caps? And what makes them
> bulge/leak, anyways?
> 

The story I've heard is that industrial espionage in the late '90s 
resulted in the theft of an incomplete formula for the electrolytic 
capacitors.  The missing ingredients provide the long-term stability of 
the caps.  Without it the caps degrade after several years and over heat 
which causes the bulging.

I've had good success with replacing bulged caps with ones salvaged from 
P1 and P2 systems, as these were manufactured before the incomplete 
electrolyte formula was in use.  The first repaired mobo using this 
strategy has been in use for 18 mo without any problems, and others for 
shorter periods.  None of the repaired board have failed as of yet.

> And, are bulged caps always a sign the capacitor is bad or just one of
> those situations where if things aren't working as expected, and the
> capacitors look damaged, that's probably the culprit?
> 

Bulged caps are evidence of a failure or soon to fail.  At Free Geek 
bulged caps are criteria for consigning a donated system to the 
non-functional category.

> Sorry for the "electronics 101" question, but I would have never
> thought of fixing my own mobo.  Intriguing!
> 

Patience and basic soldering are the only skills required.  Since the 
mobo is non-functional anyway it's all good if you can make it functional.

> PS: Complete respect for what freegeek does.  What an incredible
> community service you provide there.
> 
> Angelo
> 
> 

Larry