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Silencing Macintosh II


So, I have a Mac II but… Man, the fan is rather VOOSHy, almost like a vacuum cleaner!

Anyone had success replacing the PSU fan with something quieter? I understand that the PSU fan is the only thing cooling the entire system, but I'd still like to make it quieter…

The Mac II uses a Panaflo FBK-08A12H fan, these are the specifications according to this page.

 80x25mm  1.56W  37.1 CFM   4.5 mmH2O    35 dB-A   FBK-08A12H

I don't see any Noctua  fans that output the same mm H20 for example, any recommendations? I'm really not sure where to go here.



Well-known member
Yeah I replaced the PSU in my II with a IIfx PSU and it made a noticeable difference. I'm also interested if there are further improvements to be made.



Well-known member
I'd try cleaning it first, and re-lubricating the fan.  If you must replace, I'd go for a unit which has similar CFM qualities over the existing fan, not a ultra quiet slow model.  The fan is important in circulating air in the entire case, not just the PSU.



Not seeing too many around 37.1 CFM, I wonder if 31 CFM would work?

The thermal design of this thing isn't exactly advanced…



So, thanks to somebody else's post on one of Larry Pina's books, I took a look through the "Macintosh II Repair and Upgrade Secrets" book for information on fans and such.
It seems there was a fan controller upgrade sold by "Nova International", which connected between the fan and power supply, and used a temperature probe on a long wire to adjust fan speed.
Of course, nowadays… That particular fan controller upgrade is basically unobtanium.
So, as a substitute… I've been looking at various cheap temperature fan controller boards on eBay and aliexpress, and settled on one that features a temperature probe on a wire, and has screw terminals for power input (From the PSU) and power output (to the fan), as well as a dial that can adjust when to start ramping up fans.


I will test it out, and report back with findings!



Well-known member
That's pretty close to the same kind of setup I have in my HP 6632A power supply, mine controls PWM rather than voltage though. It works quite well, the hardest part is just finding somewhere to mount it.



Active member
How did it turn out? Did you change the fan or did you put a fan-controler in the power supply?
I am also thinking about reducing the noise and the fan is very noisy in my macintosh II.
I currently have the color-graphics-card in my setup. The 3,5" SCSI-HDD will be changed to SCSI2SD, so no heat either.
I will also put a soundcard in it (PAS16NUBUS) and a ethernat-card. If everything turns out well, I get a P33-Nubus accelerator and an NUBUS-PC Board. So that machine will be fully equiped :)