11/73 (ba23) bringup after 12 years in deplorable storage conditions

Noel Chiappa jnc at mercury.lcs.mit.edu
Sat Nov 22 21:07:31 CST 2014

    > From: Jacob Ritorto

    > I don't yet understand where to insert the resistors, but I guess
    > anywhere there's 12v and 5v would be sensible.

Alas, I don't (yet) have a BA23, so I can't offer any personal-based guidance
on how to attach a dummy load to the power system. (On the BA11-N/BA11-S,
it's pretty simple, there's a nice barrier strip, but I don't know much about
how a BA23 is, inside. I suppose I should go read a manual... :-)

Maybe I should just lend you some of my QBUS load modules? That would avoid
the whole issue, you just plug it in like a normal card. You're in PA, right?

    > So now, with no boards at all in the chassis, I do at least get a few
    > lights on the little front panel but unfortunately not the "DC OK"
    > light and still no fans. To get them to stay on, I have to kind of
    > 'trick' the PSU by turning it off, waiting a second, then turning it
    > back on.

If it's a switching power supply (which it probably is, as late a machine as
that is), it probably needs _some_ load to operate properly.

    > Would it be more sensible to just buy a commodity PC power supply that
    > has lots of 5v and some 12v, find a way to bolt it in and rework the
    > wiring to fit? Or do you think it's likely I'll be able to bring this
    > power supply back to safe, reliable condition without getting in over
    > my head?

Hard for me to answer that.. you're the one who knows how much you can
handle! Alas, I'm not an analog whiz, so it will have to be others who help
you through it, if you go that way.

    > Got lots to re-learn here; thanks for bearing with..

Hey, you're not the only person in that particular boat... :-)


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