Slightly off the schedule
I have now assembled another PVB meant to be a 'pass-thru' video device meaning it has: video RAM, Spartan 6 FPGA, 2 FPGA PROMs, and FPGA PROM MUX. There is no videoDAC or RGB connector since it is passing 16-bit RGB, HSYNC, VSYNC and pixel clock video signals to the next board.

I've been witnessing a problem the past few days: The 2 boards only work when the pass-thru board is in slot K3 and the output board is in slot K5. I will have to troubleshoot this backplane immediately.

EDIT: I see a design error. The original can oscillator spec's output @8mA. Too little to drive 6 PVBs, or even 2. The fix is an easy one.
EDIT: The problem was not in the backplane, but incorrect soldering of PVB2. Working now.

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65Org16:https://github.com/ElEctric-EyE/verilog-6502

If there's enough room between the rows of pins, connectors can be soldered very quickly. Crank the iron up full whack, run it along one side of the pins, and run the solder wire on the other side. With a bit of practice it's possible to do a couple of pins/second.

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Interesting!

Thanks gentlemen!
But I've finished this backplane months ago and it's a solid performer.
Just FYI, I haven't noticed any noise issues with 16-bit RGB data flowing at 70MHz through 4 boards. 2 of them don't even have a single bypass capacitor yet!

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65Org16:https://github.com/ElEctric-EyE/verilog-6502

tsk tsk

Understanding thermodynamics helps. It's the same principle that allows someone to walk on red hot coals and not get burned.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!