Noel,
>> If the machine HALTs on power-up, some micro coded diagnostic failed
There are no microcoded diagnostics in the 11/34.
I'm talking of that data path check up after power-on. See http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/pdp11/1134/MP00082_1134_Vol2_Sep76.pdf PDF page 40. Logic analyzer trace here: http://retrocmp.com/articles/time-scales-of-a-pdp-11-34/221-time-scales-of-a-pdp-11-34-50us Joerg
