We moved a DLT stacker recently. into the face of the machineroom aircon, and
rack mounted instead of on shelves. even with the door on the rack shut, it was
colder.

this was enough to disturb thermal equilibrium, and put a shear force on the
case, (because of the sodding rack and the rackmount on this dell unit being
pelow par) and it stopped working until we-recabled it down lower in the rack on
the shelf.

YMMV, but if you also moved the tapedrive/robot, it could be physical and not
s/w.

-George