Dead Sun Ultra2 Question-->PS or something else?

From: J'm Sm'th (smith.house_at_sbcglobal.clothes.net)
Date: 01/29/04 

Date: Thu, 29 Jan 2004 04:06:40 GMT

My trusty Sun Ultra 2 croaked last night, quietly and without alarm. I
noticed that the power was off, so I tried the power-on button the
keyboard--no go. I tried the power switch on the back--the fans spun
around about 3 revolutions [as though they got a small pulse of
electricity], then nothing. This 3-rotation thing is repeatable.

So, I began to unhook hardware--first the drives, then the CPU, then the
frame buffer, all with the same result. Then I began unhooking the main
power connectors to the mother board. With all the connectors unhooked,
*nothing* happens [not even the 3-rotation thing] when the power button
is hit.

When I hook the MB connectors back up, the PS does the 3-rotation thing
[the CPU fans do the same thing].

So, my question is this: is it the PS, or could this be the MB that is
the problem? If it is the PS, how can I be sure when I hook a new PS
up, that there isn't some piece of hardware that will take down this PS
as well?

I took apart the PS [I am relative comfortable around electronics, being
a ham], tested the fuse and it's ok. Not having a schematic, and not
knowing all that much about switching power supplies, I don't know how
to proceed.

Any hints?

  

--
J'm Sm'th
To Reply Direct, Remove Clothes
..._._
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