I do see that Maxim does offer a drop-in replacement for the DS1285.
I'm curious enough about this as to contact TT next week.
Optimized assembler certainly is
different for each chip. My experience is that it can take a man year
to become half way competent in assembler for a particular chip, to
know whether it was a good choice or not. When I first did that the
choices were about 5, now there are thousands to choose from. Yet
some still have the same op codes as those five I had to choose from
in 1975 but can address much more memory and run much faster.
I was a few years behind you and yes - it takes quite a while to pump
out good assembler. The redeeming thing here is that it's just
basically control functions and and not fast fourier transforms! 8051
tech is alive an well along with it's codebase (who would have guessed
this back in the late '70s).
I also see a lithium cell on the board.
Has anyone ever replaced that cell when there was a control board
problem? Every other radio that vintage with a lithium cell has
needed replacement. That might be worth the bother in the Omni VI and
VI+.
I know from experience that an IC-751 can totally loose it's firmware
if the lithium cell dies, but I'm thinking it's more than just losing
code. You suggested a disassembler (if that would solve the problem)
but it's kind of an "in your face" thing to do to a company you like
and what to maintain relations with. But, on the other hand, if someone
would just "happen" to acquire the code through disassembly or by some
other means, the problem could be solved to everyones satisfactions -
if in fact it is code-related.
Since there is a lack of information, I'll give it a rest until I can
ascertain more facts next week and then continue from that point. Maybe
someone at TT will be in a sharing mood by then.