Adrian Graham binarydinosaurs at
Thu Feb 25 03:51:15 CST 2010

On 24 February 2010 21:26, Tony Duell <ard at> wrote:

> I've not checked the prints, but I would have thoguht it was jumper 1-2
> and 3-4 for 115V and jumper 2-3 _only_ for 230V. As you've worded it, it
> suggest you mean to jumper all 4 terminals for 230V (which I suspect
> whould chort out the mains!).

You are indeed correct, there's 2 windings in the transformer that 2&3 join
together.  After I'd dismantled it and worked this out someone told me it's
a 115V box anyway!

> Well, if they plugged it into 230V, it sounds like it. But 115V outlets
> are not totally unheard-of in UK factories, etc, so it's possible it was
> strapped for 115V and used on 115V


> Incidnetally, there's at least one DEC PSU -- and I think it might be
> this one -- that has an inrush limiter resistor that's shorted out by a
> relay once the supply has got going. If this relay doesn't make properly,
> the resistor gets left in circuit, and gets hot and bothered as a result.

I'll check tomorrow. Didn't have a chance to do much else with it yesterday
other than a visual to check for obviously blown components of which there
appear to be none, certainly nothing that looks like it's let the magic
smoke out...

Owner of Binary Dinosaurs, the UK's biggest home  computer collection?

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