I installed a cooling fan in my G3

Hello,

The only option I could think to propose, would be to put it on a thermal sensor. There are sensors that are designed for PC builders. Those sensors draw power from the hard drive connector (like you powered the fan), and then can control whether or not the fan is powered or not based on temperature (you would plug the fan into the sensor for power).

You would attach the heat probes / sensors to whatever you wanted to base the activation temperature on (CPU, hard drive, ambient temperature, etc.).

That would be about the only option I would see since the iMac does not have a control mechanism for the fan.

Now, if you were up to designing your own electronics, you could devise a sensor / controller mechanism that would activate or shut-down based on the state of a component (such as the hard drive). But, that is not something you'll find pre-built. I used to get into things like that, but it would take a lot of money to motivate me to produce something like that now (just don't have the time or interest anymore).

Otherwise, just let the fan spin.

I have an iMac G3 Lime 333 MHz that came with a factory fan installed. It's fan spins all the time and only turns-off if the computer is completely off. Even when it's asleep, the monitor is off, the hard drive is off, and so on, the fan runs at full speed. I just haven't cared enough to alter it.

I hope this helps.

Let us know if you have other questions.


P.S., if you'd like, go ahead and click the "Helpful" or "Solved" buttons on any of the posts / replies above if you feel they were helpful or adequately answered your question.

I hope that fan is blowing "out" instead of "in."

I don't know... those fans probably last longer if they are continuously spinning rather than having to stop/start every time you let it sleep/wake. If you don't mind the noise, it should be fine that way. I've had Macs that run all day, and if there was a failure, it was not the fan.

However, maybe you can wire up a USB (or Firewire) connector that powers the fan. Those ports should be off when sleeping. You'd have to find a spot to pass the cable into the case, or course, but you'd have a convenient "on/off switch" outside the case for the fan.

Hello,

Yes, USB power is one option. But, it should be considered that it would reduce the power available to USB devices. So, you might lose the ability to use some USB accessories.

Additionally, not all USB ports turn-off +5v power to the port.

And, that would also mean verifying that you are using a +5v fan and not a +12v fan.

The 12v fan will run on 5v (at least many will). But, it would spin considerably slower.

I'm sure the fan does far better than convection. However, to ensure the fan was operating effectively, you'd have to find a way to seal "around" the fan and the opening so that it was really doing 30 CFM (and not just blowing some of the air around the inside of the case).

Hello,

Yes, the temperature switch would be a convenient solution. Set it up, and forget about it 😉

Sounds like that might work for you.

As for convection vs. fan, I don't think you could adequately compare the two.

Basically, convection works on the theory that hot air will rise, and you just need to give it a way out.

Fans, bring in cool air by sucking air through the case (if the design is efficient. Basically, by exhausting air, you create a draw that will suck fresher cooler air into the computer through the opposing air vents.

Of course, there are various factors in design that enhance or hinder cooling. So, theory / operation will potentially be affected by poor design 😉

But, in general, adding a fan is better than just letting it drift out.

I hope this helps.

Let us know if you have other questions.


P.S., if you'd like, go ahead and click the "Helpful" or "Solved" buttons on any of the posts / replies above if you feel they were helpful or adequately answered your question.

A fan sounds like fun - but isn't it also superfluous - I mean, did your previous hard drive die from overheating?

{NB : I am NOT trying to squash engineeeeeering creativity here - necessity [and plain mucking about and experimenting] has the been a most willing mother for invention}

But most convection-cooled G3's seemed to run okay the way they were designed to (another example of creative engineering) - although it never hurts to try and keep internal emperatures down.

Which brings in a new topic I suppose - don't some hard drives - Seagate for instance - actually run cooler than some other brand hard drives? If that's true - then that's a factor to consider.

I know that putting the display to sleep often (something you can do while you're playing through an itunes playlist - but not when you're creating a amsterpiece in PhootoShop) seems to keep the temps down somewhat.

Just given an option to your idea rather than a helpful opinion.

ciao

Gregg 🙂

I do hope the new drive (Western Digital 80GB, 7200rpm, 8MB cache) runs cooler.

I have a Western Digital 120 GB (recent so it's the same series as yours most likely), and it runs VERY cool. It's in an external drive case, and it barely gets warm. Also very quiet.

I like your idea, because in addition to hard drive failure, a cooler-running iMac will make the analog video board last longer (I think). That's the part that most often fails first, and it's a lot harder to fix than the hard drive.

You should have gotten one of those crazy LED lit fans. That would have looked "unique" inside the translucent case.

P.S. I could have just tossed the machine as it's not
worth anything. But it was fun to make a project out
of!

Well I'm glad you did keep it and make a project out of it.
I've noticed that fans have returned in the G5's - I was looking at a pdf on the pulling apart of the G5 and thought how much simpler taht it was than the G3's.

Also I've heard that you can now get a fan unit that fits onto the G4 cube's - which should probably make them last longer as well.

I"ve got 4 G3's that operate on convection only - while the two 233's have inbuilt fans - but so far I don't believe that I've had any heat problem with them - and they are all second hand - I think 3 of them were used in schools (uggg!)

The only prob I've ever had with heat corrupting things was with my old Performa 580CD on an extremely hot day here in Perth - and the claris software was acting like a drunk - so I switched it off til the (relative) cool of the night - and it then functioned flawlessly.

anyway - more power to you - and maybe a little internet searching will add ammo too your creative ability - I know the Xceler8yourmac site has some novel reports.

see ya

Gregg 🙂

Cool. Give us a picture of your iMac in action (in a dark room)...