23 (1998)
When their other computers prove to be inadequate the guys buy a second-hand "PDP-11", in fact an AS/400, to help them crack passwords, but are unable to use it because of a lack of three-phase power and air conditioning.
Well it's not a PDP-11, but even given that the AS/400 would have been more or less new when this film was set and buying one second hand would not have been feasible.