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Fans.....who needs 'em?


Well-known member
I have been refurbishing a couple of PowerMac 6100s and a Quadra 660av.  I've noticed that the fans in those machines are pretty loud (probably because they are pretty old!).  Since I have replaced the hard drives with SCSI2SD devices, and since the CD drives don't see that much action, I'm wondering what the group thinks about the wisdom of going fanless.  I realize the PS will likely heat up pretty good, but if nothing else is throwing off heat, maybe convection can take care of that?  Or should I just find some "quiet fans" to replace to old fans?





Well-known member
Maybe investigate a modern power supply that can replace what is in the machine that is designed to run fanless. Power supply technology has also improved but it is always going to cost more than a couple of good, quiet fans. As another alternative look for solutions that place sensors on the telltale hot parts of equipment and increase fan speed accordingly, that way you can avoid having fan noise until it is needed. Sometimes it will be needed and there is no getting around that. I would never run without fans completely.



The Steve melted many a 128k top grill that he'd never wanted to be there in the first place. I imagine you could build a MacChimney to draw the PSU heated air up and out along with the rest of the heat generated by the internals, but quiet fan's aren't nearly that tall or unsightly. Power/cooling budget is yet another thing that took a back seat to styling at Apple.



Daring Pioneer of the Future
Staff member
6100 recase project where instead of a chimney, the whole thing goes into a slim vertical case with mesh bottom and top to let the heat rise out /s

With replacement PSUs, I bet the 660 would be fine, especially if the CPU does not already have a heatsink, and you add one.

The 6100's 601 is reputed to make more heat. With no cards in it, and a SCSI2SD instead of a conventional hard disk, the pressure is off a little bit. Going for a more modern PSU or an external PSU via something like a mAcTX, if one will be made for the 6100, will take some pressure off too. I'd say that a 601 (especially a slow one as in a 6100) with a heatsink shoudl be good, but it's worth being careful attaching heatsinks to 601s, I believe there's slightly more to it than an '040.

Noctua has a good reputation for quiet fans, so whatever Noctua would be a drop-in replacement for the extant fan is probably fine.



Well-known member
If you somehow want gold colour fans, SilenX is also a pretty good brand.

Part of me wants to install one of those tacky gamer fans with RGB lighting in a compact Mac for sh*ts and giggles!



Well-known member
I'm in the same boat. They have a line of gray and charcoal fans now it seems, though...

Also, they don't have as many sizes as Noctua, but I'm a fan of be quiet! brand fans.
They have the Chromax line these days, which are black fans with a variety of colored rubber bumpers (including black for a simple look), as well as their black industrial line of fans. The gray/charcoal ones are the Redux line, which is essentially the budget option. They're older Noctua designs.



Well-known member
I put a Noctua fan in my CC for the same reasons as above. Admitedly, being that I never see it, it never even crossed my mind that that it was an ugly color...but it was a very very worthwhile upgrade.



Well-known member
So I’ve been doing some research to try to find fans that will replace the fans in my 6100.  I’m looking for any good tear down guides for the power supply.  Googling has been locating nothing.  Anyone have a source for a tutorial on tearing down the power supply?



Well-known member
I just put a Noctua in my Quadra 700 power supply and it made a world of difference, noise-wise. The air that's coming out is quite cool, but I have noticed that the CPU heatsink feels, how to describe it, not uncomfortable hot, but fairly warm if I take the cover off right after shutting down. I've removed the floppy drive, not sure if that's messed up the air flow... But it's held up for a couple of long sessions with no weirdness so maybe it's fine? I might be picking up a 7100 soon, and I'd want to give it the same treatment.

I'd like to get some sort of temperature probe to know how hot things actually are,and also compare different fans etc. Any recommendations there?



Well-known member
I bought one of these a while back for this purpose. Works great though you might want to solder in an extension to the thermistor probe wire, it’s probably only about 8” long.  https://www.amazon.com/dp/B01L1DLPWG?ref=ppx_pop_mob_ap_share

Separately I had a silly toy project last winter to hook up an Arduino Nano to a thermistor, do the math to read the temperature and then convert Arduino serial to a Mac-readable serial signal dumped to a DIN8 cable I could plug into my SE30 and display the internal temperature on screen via software. I actually got it working and even made a custom PCB (not shown - photo is the early breadboard edition but the software works - note 73 degrees displayed on the screen) for tidiness but never cleaned it up completely because we had a lovely baby. If anyone might be interested in such a contraption maybe I’ll make it available as a kit one day. The pcb and parts are cheap, but you would need to supply an Arduino Nano. 


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