The DEC82xx parts seem to be the Signetics 82xx parts.
FWIW, I can now confirm that the Signetics N8235 will work for the
DEC8235. Another collector kindly gave me a couple, and I'm set for those
now.
I replaced the 8235s and another bad IC on the TD8E that I found after
that (a DEC5380, which seems to be the same as the SP380, which is also the
8T380 which is also the DM8836 :-), and the TD8E appears to be OK.
Or at least better; it's still not working but now I'm convinced that
there's something funky going on inside the drive's electronics. I'll have
to track that down next.
Thanks again,
Bob