[grom371]

Hi
I'm looking for a model of capacitor for SGI 013-2304-001 Octane XIO to PCI Card cage
It exploded and it is impossible to determine its model.
Please see photo
Thank you!

[weblacky]

OK I have good news and some bad news.  You're lucky I tend to take random pics of stuff I get before installation :-)

OK, Good news...here's a great pic of that region.  Bad news, it appears I have a different revision of the board.  HOWEVER, all the components in that edge region do in fact match the VALUES from your picture, just not the supplier/part # of that manufactucturing run.  Short answer, I believe my cap values are the same as yours, but some of my board layout isn't the same. 

Take with a grain of salt.

Cap value in position C25, I have is a Tant Cap 22uF 35v.  So I'm about 99% sure yours was too.

   

[grom371]

Thank you!
I have installed a capacitor but the system will not boot. The server turns on, but the IRIX does not start.
If I take XIO to PCI Card cage out, the system starts good.
Probably something else burned out, but visually examined all the boards and all components are Ok.
I'll leave it as is now

[weblacky]

I would temporarily remove the cap and use diode mode on a multimeter to check the pads. If you find a short then continue the investigation accordingly. If that cap was used as a decoupling cap to ground, there maybe additional damage at other sites (also remove all pci cards from cage).

A burnt cap like that could be spontaneous, but more likely was a symptom of under regulation or the presence of ripple or AC. It’s also possible that a neighboring semiconductor went short and took out the cap by connecting voltages it shouldn’t. But I’d bet you’ll find additional symptoms if you probe around.

[Irinikus]

Not related to this case, but...

When I first got my AlphaStation 255, it had one of these tantalum caps blown in the PS/2 connector circuitry for the keyboard - a common symptom that these machines seem to suffer from.

After doing some research I noticed that on later boards, DEC fitted the cap the other way round. (Incorrect polarity in the original circuit layout was causing it to blow!)

When I fitted the new cap, I fitted the way it was fitted on the newer boards, and the system's functioned perfectly ever since!

[grom371]

Thank you, I will give the module to electronics engineers who work in our company for research.
I will inform about the result later