Re: UDC short mystery - 2 different cards that both hate my Apple 5 1/4" - Different revs?

["Michael J. Mahon" <mjmahon@aol.com>]

atfphotography@gmail.com wrote:
> Hello,
>
> I recently resurrected a dead UDC short by swapping in new caps. Also
> I was able to pick up a UDC short from a fellow vintage connoisseur
> here (thank you ]3ob!).
>
> You can see pictures here;
>
> http://www.atfphotography.com/udc/
>
> I was curious that my original "gold" card is missing parts from the
> "green" card. Might it be a later version that didn't need those
> parts? I also noticed the green had wire-wraps on the back.

From the date codes on the chips, the "gold" card was manufactured
in late 1990, while the "green" card was manufactured in mid-1987.

I wouldn't be surprised if there were substantial firmware and hardware
revisions, and even specification changes, in that period.

-michael

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