[rescue] SUN Ultra 24 4-pin power switch

Richard ejb at trick-1.net
Wed Dec 19 19:28:18 CST 2018

Hi Matt

#include disclaimer

So if you have some way to test continuity or if you can trace the tracks easy
enough I would suggest working out which pins on J12 of the photo are bridged
when SW1 is pushed bonb. Then I would look to get the right sized IDC
header and some cable to break out the two pins.  You then need to connect
these two pins to the ATX power control pin and gnd per the following


By bridging power PS_ON# and ground the supply will power on. This is where
the switch needs to connect to. I am assuming you are replacing the PSU also
in your mod.

Hope that helps


Sent from my iPhone

> On 20 Dec 2018, at 03:17, Matt Smith <matt at mattsmithcodesmith.com> wrote:
> I thought I would ask here to see if anyone has done anything similar.
> I'm reusing my old (to me) Sun Ultra 24 case with modern components. I know
> it's not the coolest thing SUN ever made, but it's nostalgic to me. This
> been more or less easy so far since the 24 was all boring ATX components in
> the first place.
> The only thing that I can't figure out is the power switch. Sun used a
> panel I/O board that has a 4 pin power switch. I've only ever seen 2 pin
> power switches. From looking at the PCB, pins 1 & 2 are power and 3 & 4 are
> ground. The old motherboard is a ATX standard Intel chipset, so I don't
> think Sun would have done anything too crazy with the front panel headers
> there.
> Here are some pictures:
> https://imgur.com/a/xcCjSoI
> Thanks for reading!
> -Matt
> _______________________________________________
> rescue list - http://www.sunhelp.org/mailman/listinfo/rescue

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