IBM 8143 Board Recap

[stc_it]

I am new to this forum so excuse me for posting something that might have been covered before.

I have an IBM Thinkcenter 8143 and the board is made by foxconn and the ibm part number is FRU29R8260 if that helps my upcoming question about a bad cap.

This system stopped working and is out of warranty and after looking at the board I noticed one of the caps was bulging. If you can pull up a picture of this board, it is the cap right next to DIMM 1 and 2. It is a dark brown and goldish looking cap. The numbers on the cap are 1500uf, 10V.

My question is for me to replace this cap, do I need to use the same exact cap with the same numbers or could I use a different cap with highger or lower V or higher or lower uf? I work for an education insitution and we have older p4 computer laying around that are out of service than I can still a cap off of. I also have a Dell junker that I can still a cap off of as well. The dell machine only has a few caps on it and they are 1000uf, 16v.

Any suggestions, guidance or answers would be appreciated.

Thanks

[sofTest]

Re: IBM 8143 Board Recap

You can use a capacitor with a higher voltage rating (V), if it fits physically, but you should not change the uF. Also, be certain that the new capacitors have the same or better ESR than the old ones.

If in doubt, please post back with make and series of old capacitors (all markings), and the same with the alternatives you got.

[stc_it]

Re: IBM 8143 Board Recap

All the caps on the board are Rubycon.

The cap that is bulging is a KZJ series 1500 10v. I don't see this cap listed in the kits.

Instead of using a cap on some other boards I have, I may just order some new ones.

I will have to get a meter and check the esr.

[sofTest]

Re: IBM 8143 Board Recap

I think you have to look again, KZJ is a Nippon ChemiCon (NCC) series capacitor. If so, you can replace with Nichicon HZ, Samxon GA, Rubycon MCZ, Samxon GC, and of course an identical one. Of Ebay, this or this should to the job.

[linuxguru]

Re: IBM 8143 Board Recap

Hmm - then it appears that KZJ does not fix the issues with KZG, which isn't too surprising - they apparently use similar or identical electrolyte.

[PCBONEZ]

Re: IBM 8143 Board Recap

Yes there is some Chemicon page somewhere that says KZG and KZJ use same electrolyte.
KZG and KZJ should have same heat problems.
Don't see KZJ reported so often as KZG because they are used less often.
.

[stc_it]

Re: IBM 8143 Board Recap

The cap that is bad on the board does not have any name markings on it, or none I can see, only what I posted. The rest of the caps on the board are rubycon and some look just like these except these are a smaller diameter. So sorry for the confusion if I was wrong about these. I assumed wrong.

There are 3 of these in about the same area, would be better to replace all 3 or just the one bad one?

Thanks again for the info.

[linuxguru]

Re: IBM 8143 Board Recap

Replace all the KZJs in the VRM section with Rubycon MCZ, MBZ, Nichicon HZ, HD, HM dated 2005 or later, Panasonic FM, FJ or similar ultra-low ESR caps. If you can, replace all the KZJs on the board with values greater than or equal to 470 uF. Do not use KZGs or KZJs in any location where it is subject to heat, including vented hot air from heatsinks, or conducted heat from devices like FETs. Neither KZG nor KZJ live up to their specified 105c temperature rating in high ripple-current applications.

[stc_it]

Re: IBM 8143 Board Recap

By what your telling me here, the uf doesn't matter on these as long as it is above 470 and the voltage is either 10 or higher? Sorry if I am misunderstanding you here.

Thanks

[linuxguru]

Re: IBM 8143 Board Recap

No, I mean replace the KZJs with good caps of the same or similar value as the original, but you need to replace only the caps with values of 470 uF or higher. The smaller-valued KZJs can be left on the board, since they're unlikely to fail quickly.

[gdement]

Re: IBM 8143 Board Recap

I understand skepticism about KZJ, when KZG has shown heat issues. But honestly I've seen many more reports of MCZ failures (again with heat), and we generally accept those as good caps. This is the first report I've seen of a KZJ failure so far.
I'm not convinced if KZJ is better or worse than it's competitors. I just don't see evidence to draw such a conclusion.

Yes there is some Chemicon page somewhere that says KZG and KZJ use same electrolyte.
KZG and KZJ should have same heat problems.
Don't see KZJ reported so often as KZG because they are used less often.
.

The marketing BS says they use the "same" electrolyte, but I don't take that very seriously. It might be similar, or maybe whoever wrote that just made it up. It's marketing after all.

*something* is different about these caps, or else they'd have the same specs. They also might not be manufactured in the same facility - maybe KZG is a 2nd rate operation.
Maybe the quality of aluminum isn't the same. Maybe the quality of the electrolyte is binned for KZG if it isn't a great batch. Or something else - who knows.
It's possible KZJ is as heat sensitive as KZG, but I don't see a record to show that yet.

I suspect these ultra high end caps just live a tortured existence, and they may all suck over the long haul. Thus why so many modern boards use polymers.

[PCBONEZ]

Re: IBM 8143 Board Recap

I've had KZG fail one several boards with no bloating at all.
Bad MCZ bloat.

Off the top of my head the build dates would range from 2001 thru ~2005.
That's a heck of a big batch.

[PCBONEZ]

Re: IBM 8143 Board Recap

Most (maybe all) bad MCZ I remember reported bad were in Dell GX/SX type mini-ovens.

The KZG I've had bad were in standard uATX cases with not too bad of air flow and most CPU's were like < 2Ghz Celeron.

.

[gdement]

Re: IBM 8143 Board Recap

I was talking about KZJ, not KZG.
It's well established that KZG has problems, but KZJ is just speculation.

[stc_it]

Re: IBM 8143 Board Recap

Well I finally replaced the bad cap on my IBm board and had some results but not what I wanted. Before the cap, the machine would not do a thing. now with the new cap, it comes on and the fan starts surging high then low and it keeps doing this till you pull the plug. I think this board had other issues other than the one bad cap. I noticed beside the bad cap was a black surface mounted circuit that looked like it was burned pretty good. This machine may have taken a bolt of lightning, I wasn't told what happened to it so I am just speculating.

Just checking to make sure what I bought was correct to replace what I had bad here.

Bad: 1500uf KZJ 10v
Replacement: Rubycon MCZ 10v 1500uf

Thanks again for the info and help.

[gdement]

Re: IBM 8143 Board Recap

Yes, that replacement is fine. They're equivalent specs.

[Wizard]

Re: IBM 8143 Board Recap

keep replacing other caps as well.

Cheers, Wizard

[PCBONEZ]

Re: IBM 8143 Board Recap

I was talking about KZJ, not KZG.
It's well established that KZG has problems, but KZJ is just speculation.

KZG and KZJ use THE SAME ELECTROLYTE (according to a Chemicon ad) and so will have the same heat problems.
Manufacturer flat says they are the same in regards to what causes the heat problems.
- That's more than just speculation if you ask me.

Bad KZJ don't show up often primarily because they aren't used very often.

Marketing wise...
KZG <~~> MBZ
KZJ <~~> MCZ

KZJ are higher grade and higher cost than KZG and so seen less often.
I ~think~ KZJ are priced higher than MCZ bulk/wholesale so builders tend to choose MCZ (for the Rubycon label) if they want lytics with ESR that low.

.