Macintosh II fan speed controller hack (circa 1993)

[David Cook]

I recently purchased a Macintosh II without seeing a picture of the inside because I like to live dangerously.

Upon receiving and opening it, I saw a cable running from atop the hard drive and around to the power supply. The hard drive had a temperature probe taped to it.



From there, the cable sneaks into the power supply near a little box cable-tied to the lid.



Opening the power supply is relatively easy (just two screws). I suppose that is to allow the fuse to be replaced?



The little black box connects to the temperature probe. There is a power connector that goes into the original power supply fan connection. The original fan then connects to the little black box. This nice little setup is easy to install and remove.

The fan is very quiet when the computer is first powered up. Subsequently, it does speed up and become a little noisier. However, I never really thought of the Macintosh II as a loud machine (compared to a Quadra 950, for example) in the first place. Apparently, the original owner disagreed.

- David

 

[saybur]

That's a neat find, quite clean as mods go. Maybe the previous owner upgraded from a pre-SE compact and was unhappy their machine was making fan noise at all?

 

[finkmac]

oh yeah this was a commercial thing. it's mentioned in a book from the time... possibly one of the dead mac scrolls books?

i was going to do a similar sorta mod as the fan noise was annoying me in the past.

enough people considered the II fan to be loud that apple went with a variable speed fan in the IIfx

 

[David Cook]

it's mentioned in a book from the time.

Well spotted!