[rescue] SPARCserver power supply

Lex Landa brooknet at imap.cc
Sun Jan 2 20:12:25 CST 2011

Hello Michael - thanks for your reply.

On Sat, 1 Jan 2011 08:35:20 -0500, "Michael Thompson"
<michael.99.thompson at gmail.com> said:

> One of my 3/80 systems vaporized a tantalum cap on the motherboard and
> kept on working. It still works fine.

My cgthree doesn't start up now, and displays corrupted graphics (bits
randomly moved around, and stripes).  Sometimes the display doesn't
appear at all.  Whatever happened when that capacitor 'frizzled', it'll
need fixing (see later).

> As far as I know all of the CG3/cgthree frame buffers are
> architecturally the same. There are quite a few different physical
> implementations for the VME bus, S-Bus, and P4.

Thanks.  I see that they're quite cheap as well, and there are some UK

> The backplane is removable, but it takes a bit of work.

That's what I'll be doing, then - it'll mean moving the computer into a
bigger room, and with those two rooms facing north, it's very cold in
there.  This will have to wait until spring (I can't afford to heat
those rooms so I tend to 'hibernate' in the kitchen).

> I think that reverse polarity from the power supply is unlikely. I
> have seen lots of tantalum caps just vaporize.

I agree and add that I've never seen a PSU reverse the polarity of its
outputs - unless I've connected something the wrong way 'round - so that
was a bit of a wild guess from me.  I wonder what makes the capacitors
do that?  The Wikipedia article on Tantalum mentions a very thin
dielectric layer - maybe this wears out over time.



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