🚀 go-pugleaf

We have a number of NeXTdimension boards that have been damaged by us in
"little accidents" during development and debug of a NeXTbus board, such as
shorting bus signals and power rails etc with falling probes and test leads.

The curious things is that they have all failed in the same strange way, and
so I was wondering if anyone else has had the same problem, or has any clues
what might cause it. The damaged ND boards appear to operate correctly in every
respect, except that the monitor windows do not appear: the boot sequence,
NMI monitor and panic windows simply don't show, although the machine still
waits for & responds to key pressess expected by the windows as normal.

All the documented NBIC registers read the same as on working ND boards, and
replacing the NBIC chip on the damaged boards had no effect.

Does anyone have any idea what might cause a NeXTdimension board to not display
system windows, but to operate correctly otherwise?.

thanks,
Graham