electrolytic caps used to be more reliable, the US brands were copied by the japanese, who were copied by the koreans, who were copied by the chinese. each copy got a little more on the cheaper side, till they dont last very long now.
also, electrolytics fail because of the worng voltage on them. I have replaced caps with only 1.5 volts across them where the cap was rated at 50 volts. the electro chemical process in the caps needs the proper voltage to keep working. older caps were marked in WVDC, or working volts dc, the voltage they were designed to work at. you dont see that much any more. using a cap at way below its voltage rating causes it to decrease in capacitance over time.

 

Operating temp affects it most and most people incorrectly assume the cap maker's data sheet specs reflects AMBIENT temperature which is not correct. Ripple current causes the capacitor to run significantly hotter than ambient... hence their short life.

I was not saying the faults are downright caused by ambient conditions, I said even ambient conditions come into play when considering how a circuit works and how long it lasts. I meant it as an example showing how far the range of causes of failure extended. There are, of course, a lot of little things that affect it even more. I just meant that there are many, many different causes for failure that even includes atmospheric conditions.

 

Maybe the capacitors eat to many electrons?

 

electrolytic caps used to be more reliable, the US brands were copied by the japanese, who were copied by the koreans, who were copied by the chinese. each copy got a little more on the cheaper side, till they dont last very long now.
also, electrolytics fail because of the worng voltage on them. I have replaced caps with only 1.5 volts across them where the cap was rated at 50 volts. the electro chemical process in the caps needs the proper voltage to keep working. older caps were marked in WVDC, or working volts dc, the voltage they were designed to work at. you dont see that much any more. using a cap at way below its voltage rating causes it to decrease in capacitance over time.

I had always assumed the rating was maximum! I had no idea under voltage was damaging as well, there you go another thing learned!

 

electrolytic caps used to be more reliable, the US brands were copied by the japanese, who were copied by the koreans, who were copied by the chinese. each copy got a little more on the cheaper side, till they dont last very long now.
also, electrolytics fail because of the worng voltage on them. I have replaced caps with only 1.5 volts across them where the cap was rated at 50 volts. the electro chemical process in the caps needs the proper voltage to keep working. older caps were marked in WVDC, or working volts dc, the voltage they were designed to work at. you dont see that much any more. using a cap at way below its voltage rating causes it to decrease in capacitance over time.

There's a "badcap" page online somewhere that tells the story of industrial espionage in China, apparently an electrolyte formula that was incomplete was stolen and shared around.

That all happened around a decade or so ago and dodgy caps are still turning up in various places.

 

Hello,

There is even a "badcaps" forum, dedicated to PC's laptops and other computer periphials:
http://www.badcaps.net/forum/index.php?

Bertus

 

Hello,

There is even a "badcaps" forum, dedicated to PC's laptops and other computer periphials:
http://www.badcaps.net/forum/index.php?

Bertus

thats a good read! but I cant help thinking some of those guys go a bit too far! they seem to pay alot of money to recap a motherboard that dosnt cost much to start with! but I did find alot of good info

 

Hello,

There is even a "badcaps" forum, dedicated to PC's laptops and other computer periphials:
http://www.badcaps.net/forum/index.php?

Bertus

I'm a member over there. They seem like a good group of guys, though they definitely tend to be more opinionated than anyone here

 

thats a good read! but I cant help thinking some of those guys go a bit too far! they seem to pay alot of money to recap a motherboard that dosnt cost much to start with! but I did find alot of good info

When I scrap a motherboard I salvage any caps that aren't bulged, once or twice I've replaced MOBO bulged caps from this resource - I've never spent any money on recapping a MOBO.

 

I recapped a W98 MOBO. It worked!
Of course, that was a long time ago.