[rescue] Perverse Question

Robert Novak rnovak at indyramp.com
Sat Jun 7 12:55:27 CDT 2003

On Sat, 7 Jun 2003, Al Potter wrote:

> Gawd, I love stiring up a hot topic....    8-)

Heh. No goth babes to rile here, but...

> I guess what would be ideal, if there was such a beast, would be a
> replacement mainboard of IPX/IPC size, with compatible power connectors,
> but with mini-itx guts.

Agreed. If something of similar size and power capability were available
in MIPS or AXP processors, it'd have more cool points and (at least for
AXP) similar 'puting power for the space and power used.

Maybe some of the people who want you dead for wanting to use a good case
will send you some free Cycle upgrade boards for these critters. :) There
were Cycle 5-IP boards that would take you as high as 125mhz MicroSPARC.

> Now, back to the real question, which was would the IPX/IPC power supply
> be convertible to feed a mini-ipx board through an ATX connector. I had
> not considered the power-on issue. How does that work with a "proper"
> atx supply?  Is it never totally off or something?

I believe it is never totally off whilst plugged into mains. Most of these
boards have a LED on the board that is on when power is fed to the PS,
even if the PS is "off." There's a low amount of voltage fed through the
board, enough to do something if the momentary-contact power switch is
"closed." And I believe this is the case with any system that can be
powered up through any means other than a physical two-position on/off

Note that this is probably also the case with many Sun systems which are
capable of powering up via keyboard. I just thought of this. I can't
remember if the IPX and IPC and ilk work with keyboard-initiated powerup,
as I haven't used a keyboard on one in years, but if so, the capability
*might* be there. 10s can be soft-powered-off from the prom if there is a
supported keyboard connected, as I recall... Tatung 5s and 20s should be
the same way.

I'm pretty sure newer rocker-momentary switch Ultras are this way, as well
as the 4/5/20 machines with similar switches. Pulling the plug (or
otherwise removing mains power connection--i.e. turning off an outlet
strip that the plug is connected to) is the only way to completely remove
power from these systems.

You may be onto something here. I still wish someone with a bit more clue
about power supplies would respond to this. It could be a cool use of the
remaining bits of some systems. I've seen some that from the smoke marks
are probably not rescuable without a few thousand dollars worth of time
and equipment, and I don't think anyone on rescue is stupid enough to
think a random IPX is worth a thousand dollars to "save."


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