13 Aug
2006
13 Aug
'06
11:23 p.m.
From: "Ethan Dicks" <ethan.dicks at gmail.com>
That would be a lot cheaper, but would sacrifice some of the "vintage"
aesthetics :-).
Sure. One could use keyed 20 pin receptacles, and 18 actual pins.
Sure, and depending on how closely one followed the old schematics, that
might
still be needed :-).
One would certainly have to pay extra for the look-alike over the
work-alike.
On 8/14/06, vrs <vrs at msn.com> wrote:
> I'd start out by building replacements for the Rxxx and Sxxx modules,
all
> scaled down. (Once a few of those work, you
could start in on a
backplane
for them.)
Would it be worth the expense of a backplane? I would have thought
that the way to do it would be to lay it out on both sides of single,
largish PCB with off-board connections for I/O and front panel. > I was thinking of a 9x2 header/socket arrangement
for the interconnect
> and soldering the header to pads on each side of the board to make
little
1" wide
modules.
While the originals R and S modules were 18-pin, I'd think that 20-pin
headers, etc, would be easier to find in quantity (not that they
couldn't be trimmed down, of course). > For testing, you just need a standard size module
with a female 9x2
right
> angle connector on it, and insert the miniature
card being tested.
Replace
> an original module in some old gear with the
result, to see if you've
got
> things right. You could also use the technology
to resurrect old gear
with
missing
modules :-).
That's certainly true, but in some cases, they hand-picked modules to
get the timing right. > Another goofy idea I had (for inexpensive
interconnect) was to try to
> squeeze
> the SMT modules down into the footprint of, say, an 18 or 20 pin DIP.
It
wouldn't
look much like a replica anymore, though.
I would think the point would be a work-alike replica more than a
board-for-board form-factor-in-miniature replica, but whatever works. I would think that the individual PCB
costs, even for something about 2 sq in., and the interconnect
hardware would start to make this a rather expensive project.
I know a couple of places that will do panels inexpensively without
quibbling
about the number of designs on them. So I'd recommend panelizing about
8"x10"
of the things and produce them 30 at a time or so :-).
It
would, of course, be easier to _test_ dozens of individual modules
than a monolithic CPU PCB (since there wouldn't be any interaction
issues), but quite a bit pricier. OTOH, even with a $1000 budget,
it's cheaper than the going rate for a PDP-8/S these days.
Agreed.
Vince