24 May
2016
24 May
'16
4:49 a.m.
From: Bill Degnan
I removed the core backplanes and returned the DD11-C
to the orig
config next to the CPU. I re-inserted cards as-was. I am not getting
comms from the M7856.
Ugh. Not good. Does it respond on the UNIBUS? (I.e. if you try to read
the registers from the front panel?)
I may have shorted the card.
If you somehow plugged it into one of the core backplanes, good chance, alas.
They have either -15V or +20V (I think the latter, for the MM11-U) running
around on various pins.
(Oh, BTW, you probably already know this, but just in case not: those
backplanes take specific boards in specific slots; check the manuals/prints
for the correct slots.)
Do you have a spare M7856 you can swap in to make sure the machine is
otherwise functional? If not, let me know, I have a bunch of spare M7800's,
I can send you one (known, tested good).
Noel