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Re: [N8VEM-S100:5018] An ARM CPU on the S100 bus

Guys not at my desk right now but two thoughts. Get one of their base boards, remove the SMD sockets, copy the footprint and use it to fabricate a S100 board. For placement attach the socket to the main cpu board, place the whole thing on the S100 board with a drop of glue. Let set then remove the cpu board, check alignment then solder.

Another possibility is that these guys supply an eagle layout need to check their Web site


John Monahan (mon...@vitasoft.org)

On Aug 25, 2014 10:22 AM, "yoda" <yo...@r2d2.org> wrote:
I agree Vince - the alignment is the killer in this case - probably a jig and reflow over or hot plate is the only option - I don't think hand solder in this case is an option or you way better than the average user at doing this if you can.


On Monday, August 25, 2014 12:08:25 PM UTC-5, Vince Mulhollon wrote:
On Monday, August 25, 2014 10:09:35 AM UTC-5, monahanz wrote:

soldering two SMD connectors to an S100 board is not that hard.

The part I find completely agonizing about that board is its TWO connectors on two rigid PCBs..

I pretty much LOL at surface mount since I've been doing it for RF stuff since the 80s and I find it easier than thru-hole but to attach both connectors with less than perhaps 0.1 mm accuracy to smoothly attach would require me to build a little aluminum mounting jig or something.  Maybe for the price of those boards it would be cheaper to milling machine away the PCB so I could plug connectors into a machined board, then lay the board on top of the S100 card, then solder the connectors to the S100 board while its plugged in to the sacrificial board.

See if it was just one connector, then misalignment isn't an issue.  Or if one connector (or both) was a short cable.  Or if via the peculiarities of the board we could get away with just one connector and not install the other.  Or if a thru-hole connector were available.

I imagine soldering in both connectors and they look visually lined up but the board won't physically plug in.  Not enough just to get one connector with no opens/shorts but to get two in perfect alignment.  No trapezoids or parallelograms, perfect distance apart, etc.

Maybe use screw holes first to mount it and don't start soldering until it lines up and then hope it doesn't shift at the final removal?  Or is there a technique involving superglue?  Given the price of indium solder I don't like the idea of using it to attach the two connectors but that stuff and the hot plate / frying pan technique might work.  Then the solder on the board might not melt while I'm attaching the connectors.

I'd like to see a proto-ish board that has the 6502-ish logic to give and receive control of the bus.  Everything but the 6502 and its support.  Then solder in a "fill in the blank" that manipulates the S100 bus lines by either hardware (and glue) or software (and I/O pins) to connect a CPU.  I have to think for a second, certainly you need less than 100 I/O lines to talk S-100.  And to talk CPU-ish takes less than 40 pins.  So more than 24 I/O pins but less than 40 to talk?