On Wed, 27 Feb 2008, Peter C. Wallace wrote:
> Probably cheaper/board than the female part of CF socket...
> Even with gold, 2 or 4 layer PCBs this size should be less than $2.00
> each
Hmm. I get $5 per board, and that's assuming you can get quantity 100 of
each of the module types! For a single replica, you'd pay more per board.
I didn't get prices around $2 until quantities closer to 250 per design.
Unless you know some place a lot cheaper than I do.
From: "David Griffith":
Okay, so the sockets and boards seem to be worked out.
Populating the
boards shouldn't be too much of a challenge. Now, how about the
backplane? Can a PCB be designed that replicates the wire-wrapped
original? If so, how many layers would be necessary?
That part's fairly easy. As I mentioned, I've got a DEC style backplane
already drawn for a variation on the 8/S. All that's really required is
to define a new package and "change package" on all the components.
One issue that comes up with the DEC backplanes is that all the
connectors are right next to each other, leading to pretty dense
wiring on the backplane. Most DEC backplanes I've tried to route
as PCB's take at least 4 layers. They're also really big boards --
typically 12"x16" or more. Which means they're a few hundred
dollars each in small quantities.
If these are half-size (or less), maybe they'd drop back into the
size range where the inexpensive fabs will do them. (Most of those
seem to stop at 10"x12" or so.)
We *do* all understand that an 8/S replica is a multi-thousand
dollar proposition, right? If the boards could be done for $5
each, and the connector is another $0.50, and the components
another $2 per board, then we are looking at about $7.50*400=$3000
already, and we haven't got a backplane or a front panel, each
of which is probably a few hundred dollars. Another hundred
for the power supply, and gotta buy a pretty box. Even with
prototype board pricing and cheap interconnect I never came up
with cost estimates below about $3000 for a whole system (which
is partly why I never tried to build any of it).
Quantity discounts would make a big difference, but even so I
don't see it getting below the $2000 mark. It'd be great to
be proved wrong :-).
Vince