Not all of the EII's have fans, and those that do have a device between the power in and fan to slow it. I have been fitting a small low cfm "silent" 12v PC case fan between the power supply and floppy tray. This attaches with an in-line connector to the floppy drive power cable. Only a whisper of air seems to be required to take a lot of heat that normally warms the control panel away. You do have to fashion some sort of mounting bracket, and be careful as live mains power is in this area.
The attached picture shows one fitted between a Rev F HxC, and custom power supply I fitted.
Chris
www.thisoldsynth.com