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

tony duell ard at
Fri Feb 6 14:23:36 CST 2015

> 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.

> 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 SMPSU
in there, albeit a large one (750W? 1kW?). You may be able to reconfigure it 
for 115V mains, but watch out for the fans

> 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.

> * 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.

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

> 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...)


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