Are they bad?

[dastan]

Hello,

I hope i can get some insight from the experts.

All of a sudden i get system instabilites with my qdi kudoz 7 mainboard.
I took a look at the mainboard and a cap looks suspicious.
Since i am not am expert on this, maybe someone else could to take a look.

What do you think, is this the troublemaker ?

http://web17.s1.okayspace.de/bcap.jpg (500kb)

I am thinking abut the second one from the bottom.

[bushytails]

Do you have a photo of the ones around the CPU voltage regulators? (should be next to the cpu socket)

That one does look toasted...


--Randy

[willawake]

actually the one next to it looks a bit bulged as well but might be visual distortion from the pic.

Licon is a well known bad cap brand. It would be recommended to recap all those Licon 1000uf 6.3V. The spacing between those caps is nice so shouldnt be too hard to recap them. That J.D. cap 470uf, what is the voltage?

You have some big green caps also, what is the brand/rating. would be nice to see another pic.

Welcome to the forums.

[Topcat]

The 2 caps I circled in your pic are clearly bulging and bad, remember, it only takes one bad one to make a board unstable, there's 2 right there.

I'd replace all 1000uF and up. That'll cure it of it's instabilities.

[dastan]

Thank you for all your answers!
I gave the board a friend of mine who can solder to replace the defective caps.

Since it was asked for i made some more pictures:

The board
http://web17.s1.okayspace.de/caps/board.jpg
http://web17.s1.okayspace.de/caps/board_side.jpg

The green caps willawake mentioned
http://web17.s1.okayspace.de/caps/green.jpg

The smale one willawake mentioned
http://web17.s1.okayspace.de/caps/small.jpg
(sorry i forgot to note the voltage, but i will post it when i get the board back)

[dastan]

Today i got the board back, and what can i say, everything seems to work okay! I have to make some more tests, but didn't have any crashes so far.
my friend tested the capacitors and he told me that one had 700 of 1000 microfarad left and the other one only 500.
He also showed me one from his collection that was looking perfectly from the outside but was dried out. I hope that never happens to my board.

He told me the replacement was difficult, because there were lots of small
paths around the soldering points.

The small cap on the last pic had 10V if i am not mistaken (the print was very tiny)

Thanks to everyone who answered!

[bushytails]

I'd still reccomend replacing, at a minimum, all of the ones of the same brand... if these failed, what makes you think every other identical one isn't about to fail as well?

Replacing two caps a month would get very tiresome.


--Randy

[willawake]

yeah i agree, that was not even half the job done. Anyway if you are happy for now good luck to you. Prolly we see you back later.

The small cap i was interested because it is small but has vents on the top. So it is a 470uf 10V. Maybe even a candidate for failure even though it is small but we will see.

The big green caps I could not see the brand from your photos cos you took the photos each time from the wrong side. maybe you will be lucky with them.

nice photos by the way.....and a friend with a capacitance meter and a soldering iron is a friend indeed.