I guess I reacted to your statement
that the MM1100 was a dog. Certainly in engineering we knew what was wrong and
it was not the fundamental design. The big problem was that the "per channel "
motherboard that the 440 cards plugged into, was made with a cheaper grade of
fibreglass board, " to save cost". Unfortunately the fiberglass was
hygroscopic. i.e. it absorbed moisture like there was no tomorrow. The result
was noise, stray logic misfires etc etc.

I went out into the field once, to a studio farm near Nashville. There we
stripped all the motherboards out of 2  MM1100's, unplugged all the relays,
and washed the water & moisture out/off the PC  boards with the help of a
bucket of isopropyl alchohol and then baked them dry in the electric oven of
the farmhouse kitchen. Once this was done we masked appropriate places and
spray coated the boards with lacquer. No problems after that!!

The other problems with the MM1100 included unsealed relays which developed
rapid contact contamination from 'pot' smoke which would gather in  the back
of the bays! This would result in bad record/repro/sync switching.  Also
serious tension drift due to the effect of AC line voltage variations
affecting the tension servo! All of these problems were addressed in the
redesign of the motherboard and other areas in the MM1200. The fundamental,
design of the transport etc did not change with the MM1200, we just fixed the
bad stuff!