partial P112 kits

[Tony Duell]

> 
> Tony Duell [ard at p850ug1.demon.co.uk] wrote:
> > To tie into another thread, one of the photos of the VCF-UK
> > that I saw (I
> > can't rememeber who took said picture) seemed to be of
> > Spectrum (?) ULA
> > built from simple logic chips on large plugblock breadboard.
> > While that's
> > undoubtedly a great hack, I do have to wonder why the chap
> > didn't solder
> > it up on stripboard or similar. Anyone who has the dedication and
> > knowledge to make a copy of the ULA is capable of learning to solder.
> > And the resuylt would be a lot more permanent and probably more
> > reliable. 
> 
> At DEC I did see (but never snagged) the wire-wrapped DHV11 protoype
> (filled a BA23-size chassis). It had been wire-wrapped by an external
> wire-wrapping house and then the various snags were fixed up in house.
> 
> Perhaps the ULA builder was also a reverse-engineer and found it easier
> to wire-wrap whilst working out the design rather than building on 
> stripboard? (Was the ULA design ever made public?)

Wire-wrapping id fine, and very reliable. It's also pretty stable. Those 
solderless plugblock breadboards are none of the above :-)

I am quite sure he needed to test and modify the design as he went along, 
and maybe it;s easier to do that on a solderless breadboard (I doubt it, 
actually, I had so many problems from bad connections on those darn 
things)... But it's not had to 'edit' a design on stripboard. So perhaps 
transfer each bit to stripboard as you get it finalised?

Cerrtainly if I'd managd to make a clone of a ULA in such a machine I 
would not have kept it on a solderless breadboard, even if I'd used one 
to develop the reverse-engineered design.

-tony