PDP-11/70 Boards

[Rob Jarratt]

> > -----Original Message-----
> > From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Jay Jaeger
> > via cctalk
> > Sent: 05 December 2021 14:51
> > To: cctalk at classiccmp.org
> > Subject: Re: PDP-11/70 Boards
> >
> > On 12/5/2021 3:37 AM, Rob Jarratt via cctalk wrote:
> >
> > > Thanks for the tips. The transformer that drives the bricks is a real beast.
> > Did you find an alternative more convenient way to power them on the
> > bench?
> > >
> >
> >  From the schematics, some of them seem to want 20-30 VAC (some, like
> > at least one of the -15v regulators, take DC inputs from other
> > regulators)
> >
> > For lower current initial testing I have some 24v 2A transformers
> > lying around.  For higher current, I might use something like this guy:
> >
> > https://www.digikey.com/en/products/detail/triad-magnetics/F-
> > 401U/5032226
> 

> I have a variac rated at 2.5A. I am not quite sure whether that would be
> sufficient to test the bricks individually. Otherwise, I guess one of these
> would do the trick https://cpc.farnell.com/block/steu250-48/transformer-
> 250va-230-400v-2-x/dp/TF01418?st=24v%20transformer ?

So, to supply the bricks on the bench, would a variac rated at 2.5A be OK? I am not sure I know how much current the bricks will draw at 20VAC, and at what voltage the 2.5A rating is given. Otherwise, would this do the trick? https://cpc.farnell.com/block/steu250-48/transformer-250va-230-400v-2-x/dp/TF01418?st=24v%20transformer

Thanks

Rob


> 
> >
> > JRJ