To recap or not recap - that is the question

[silentcossack]

Hi all,

Finally able to post :-)

I'll try to be brief, since i tend not finish reading long posts. I have two e-cubes, cf-eg65 motherboards. One doesn't post (just fans spin), other works BUT... It can work for 5 hours or 5 minutes, not way to tell. USB devices seem to make it worse. Basically it freezes completely. Video is on screen, but nothing moving on screen. Only option is a reset. I've replaced every component twice, so i'm sure it's 100% motherboard. Freezes in bios bootup and os, so not os problem.

Now, i've examined very closely all caps and see no visible damage or real bulging. I think if i look long enough i will see some bulging of the little cushions between the stamped X, but it could be just an illusion :-). The caps are all "Chocon", higher values of 2700uF, 1500uF, 1000uF. I can't find anywhere in stores here in Montreal the 2700 ones of descent size. I don't want to order online yet.

I've taken out all the 2700 one from the board and tested for capacitance using a voltmeter. All those that were under 2650uF i threw out, the rest seem ok. I replaced the bad ones with 2700 from another motherboard that i had (different brand caps). Should try a power-on test tonight after replacing the tested caps.

So considering that right now i don't want to spend $15 on shipping to get $5 worth of caps, that's what i've done.

I would love to hear some expert comments on my chances, procedures, etc. This mb is purely a project, i got the cubes for free and just decided to ressurect them for fun.

I guess I wasn't that brief :-)

Thanks,
Silentcossack.

[willawake]

Re: To recap or not recap - that is the question

If a board doesnt post then the chances of a successful repair are less and there is possibility that there is more work than just replacing the caps involved.

using caps from another motherboard - not recommended
not replacing all caps 1000uf and above from same manufacturer - not recommended

[silentcossack]

Re: To recap or not recap - that is the question

Thanks for comments!

Actually, the board i'm trying to fix is the one that works but freezes (I mentioned that i have 2 of the same mobo). I'm pretty much trying to extend the life of this mobo for free, until i come across some required caps here in the city.

Anybody ever heard of Chocon caps?

Thanks.

[willawake]

Re: To recap or not recap - that is the question

yes it is possible you will have success in repairing the board you are trying to fix after replacement of the chocon caps. of course that possibility is limited by the care you take in replacing the caps and your soldering ability. also perhaps the problem is not the caps.

capacitance readings are useful in determining whether a cap has failed in a manner so that the capacitance has become very high.

but they do not show the esr of the capacitors. the usual failure mode is that the esr is becoming high.

therefore as you have a freezing problem and the caps are not a known quality make and their current esr is unknown then it is recommended to replace all of those caps 1000uf and above and see if the problem is solved.

then you have eliminated one of the unknown conditions and either the job is completed or further troubleshooting can proceed.

[Rayman]

Re: To recap or not recap - that is the question

What a coincidence; I just posted something about two of my e-Cubes (w/ cf-eg65 MB's) and one that does the fan spinning and the other that can work from minutes to hours etc right on this site. I gave up on the one that has the fans spinning (I replaced all the caps that had bulged or were discolored) and it still did the same thing. I do have my other one working (I don't know for how long...); it used to do the siren noise several times, lock up, reboot, etc. I tried different CPU's, memory etc. first... then I started replacing the caps (even though they had no signs of bulging!); I suspected bad ESR's on the 16v caps around the CPU and replaced them. The machine is running much better now.

I hope you have some luck on getting something working out of your two machines...in my case these weren't free (each one costing several hundreds of dollars.)

Rayman