23 Oct
2015
23 Oct
'15
7:37 a.m.
On Fri, Oct 23, 2015 at 7:49 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
We have plenty of the original bezels, from which it
would be easy to cast molds
(the same part is used on the 11/45 and 11/70, unlike the rest of the front
console).
Casting is one option. Another is CNC out of dense PVC foam.
The real issue in any front panel recreation is going
to be the switches (not
the plastic toggles, the actual electrical device). Both the /45 and /70 used
the now-apparently-unobtainium version with the intergral metal plate to hold
the switch in place in a metal holder plate.
It's probably possible to find small quantities of the right switch,
but not 2 dozen per panel.
So a recreation front panel is
going to have to have some new mechanical design, to allow use of standard
micro-switches - and that's probably going to mean a re-design of the plastic
toggles, as those attached to side-plates on the original toggle switches.
The pivot and attachment method is "standard" for C&K paddle switches.
You can still get switches with that arrangement, but with a different
mounting method.
I wonder how big an order of switches would be
required before some
switch-making firm could be convinced to do a run? Maybe whoever made the
'back in the day' still has the tooling to do so gathering dust in an old
room....
Good question... is it 1,000? 5,000?
To do that is going to require exactly emulating the
interface to the CPU,
which is not going to be entirely trivial. Physically, the signals all come
over flat ribbon cables to standard Berg connectors, so that won't be hard,
but I doubt the interface is documented, someone will have to puzzle it out
by reading prints - and probably looking at a working one with a logic
analyzer.
It's been done at least twice
6809-based interface (I happen to have 2 of these, so I'm good here)
http://www.pdp-11.nl/homebrew/cons1170/cons70startpage.html
Blinkenbone.
http://retrocmp.com/projects/pdp-11-70-panel-on-blinkenbone
http://retrocmp.com/projects/blinkenbone (more than just 11/70)
Also, powering the front console requires an unusual
AMP connector shell,
although that may still be available? And of course one could always bodge
the power connection...
That's a "standard" shell as used in several DEC power supplies and
for 20mA TTY connections. They get brought up on the list from time
to time. I happen to have a basket of them, but they are somewhat
rare on the open market.
-ethan