My working Twiggy drives do not feature that revision.
Strangely enough, my set has one of each. Both are marked as Rev F.
... more complex configuration
Does anyone know the story of why the analog board went through such a dramatic change?
AFAICT, they are the same circuit, the board layout was re-done. Comparing their styles, I suspect the less spread-out version was at the prototype stage, and only when the design was finalized was the board laid out again with the Apple logo and more detailed ground fill. I do wonder if there is any difference in performance and if the new layout was intended to address a known problem that contributed to the poor performance of the Twiggy.
A wild guess is the "1985" designation on the digital board is an error on the reproduction as the copper on the top side says 1982, and it is easy to be confused by looking at a backwards 2 in the x-ray view. One of my boards is 1982 in copper (on both sides), the other 1983 in copper (on both sides), with matching years on the silkscreen. Both are Rev H.
I see one of the older analog boards pictured is "E"; we don't yet have an accurate schematic history of the Twiggy analog board, are there more pics of that particular board?
Along those lines, are all of your Twiggy analog boards marked as Rev "F"?
