I pulled a current off the pins on the external floppy drive port on my Plus and wired it up using a D-connector to 2 486-era heat sink fans that I wired on over the sloping vents either side of the handle. It works well enough - the one on the analogue board side really throws out a lot of heat that'd otherwise be wandering around inside. The vents on those babies are really poor, but i think they had to be like they because of the plastic they used to mould the case and the moulding technology being a bit more limiting in 1988. A little fan assistance helps no end.