On Nov 20, 0:53, Tony Duell wrote:
> > I've been cleaning up my recently-acquired PDP-8/E, and I've had to
remove
> > the plastic foam from the inside of the lid, which was fairly horrible.
>
> Yes, that's a very common problem... Makes a right mess on a the
backplane...
This hadn't reached the completely crumbly stage, but it did smell of cat
:-(
> I have never seen conductive foam used on PDP8/e machines. There's
> nothing particularly static-sensitive in there anyway (the CPU is all
> fairly large-junction bipolar chips (TTL, etc). Mine just had the normal
> brown foam throughout.
>
> Since you can put options with top connectors anywhere in the backplane,
> there would seem to be little point in having special foam over the front
> slots only.
>
> But the leakage on conducive foam is not that high, and I doubt that
> using it would cause many problems (TTL inputs are fairly low impedance).
> It might have an effect if used over core memory units, but actually I
> doubt it.
I didn't really think it would make much difference, but I can clearly see
the impression made by the connectors for the core stack, which is
reputedly not working. The machine had modern semiconductor memory in it
when I got it -- the 1995 board I mentioned in another post -- and I've not
tried the core for myself yet.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Tue Nov 20 2001 - 02:05:09 GMT