Stupid AC wiring question (220-ish Volts...)

Josh Dersch derschjo at
Fri Feb 6 15:28:41 CST 2015

On Fri, Feb 6, 2015 at 12:23 PM, tony duell <ard at> wrote:

> >
> > I picked up a "large" machine* (for certain definitions of large) that's
> It's not that large. Or at least mine isn't, Deskside, really.

The one I have is (approximately) 5'x2'x4' and weighs about 600lbs.  I
think the 500-series was about half as tall, from what I've been able to
find.  It's not as big as a full-size rack, but it's not deskside either.
(It does have wheels, fortunately :)).

I was amused to discover a connection to the PERQ when researching this
beast (the 'PERQ-DAP' which used a PERQ as the front end) which I'm
guessing you're already aware of :).

> > I don't know if this machine works, and I'd rather not invest in 220V
> > wiring quite yet unless it does.  And, let's face it, I'm spoiled and I
> > demand instant gratification and I'd like to know as soon as possible if
> > this machine is a basket case or not.
> FWIW, mine currently has PSU problems (which is why I was given it). The
> choppers are dead short all ways round. But it is a fairly conventional
> in there, albeit a large one (750W? 1kW?). You may be able to reconfigure
> it
> for 115V mains, but watch out for the fans

Yeah, there are two supplies in mine, a big supply for the +5 and a smaller
one for other voltages, I believe.  The fans are all 240V units, so they'd
likely need to be changed out.  I'm fine at this point just getting a real,
up-to-code 240V outlet installed at some point in the not-too-distant
future to run this (and other future machines that are similarly

> > So:  since all this stuff is in the basement, I'm just about 15 feet
> > away from the dryer, which at first glance runs off an outlet that meets
> > my needs.  I even have a NEMA 10-30p plug here that I could wire up to
> > the existing power cable for the computer.  But looking into it I have
> > doubts that it's actually that simple; in particular since this house
> > was built well before 1996 and so the outlet is not grounded; there's a
> > neutral lug and two hot lugs (I assume two 120V A/C lines out of phase?)
> > and I'm guessing that might not sit well with the power supply in this
> > computer.
> This will not meet any kind of electrical code, but it should be OK for
> testing...
> The DAP doesb't care that the 230V is centre-tapped to ground (in fact
> that is
> expected in the States). The ground to the case is a safety ground only.
> So I would first check you get 230V (or so) between the 2 'hot' pins of
> the dryer
> socket. If so, then wire up a kludge cable that connects those to the
> power pins
> of the DAP and the ground pin to a good local ground (if necessary the
> ground
> pin of a normal 115V socket outlet). This would allow you to power up the
> machine.

Yep, did this last night and it worked; everything powered up nicely,

> > * An AMT DAP 610, if you must ask.  It's an array processor from the
> > late 80s, with 64x64 1-bit processors.  If the machine doesn't run I'm
> Is it as many as that? I thought mine was 32*32, but maybe you have a
> bigger
> machine. Mine says DAP610 on it.

>From the docs I have, the 510 is 32x32, and the 610 is 64x64.  My machine
has a midplane with 8 Array boards per side, and 4 large ceramic chips per
Array board (which I assume contain 64 processors each...)

> I only have user manuals, but I have thought about trying to figure out
> the hardware
> at some point. Maybe I will manage it.

I got manuals and tapes with mine; I scanned the docs and them off to Al
(and they appear to be on bitsavers now -- thanks Al!).  The tapes are
being worked on...

- Josh

> > pretty much SOL for spare parts, schematics, service manuals, or
> > anything beyond customer-level documentation (which I've recently
> > scanned, btw, if anyone's curious...)
> -tony

More information about the cctech mailing list