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Dusty Fans

I

iMacZealot

macrumors 68020
Original poster
Mar 11, 2005
2,237
3
I opened my iMac G5 today to install some RAM....I couldn't get the stick in, but I'll fix that. What I noticed was the fans, and they were incredibly dusty. Could this be why my iMac sounds like an A380? If I clean them, will it be better? How do I clean them without seriously damaging something?

Thanks.
 
Blow compressed air over them such that the dust isn't blown back into any components and you should be fine. Unless the dust has heavily built itself up in the actual fan bearings, you should notice a fan volume drop too. I've cleaned a few and noticed them to be a bit more quiet after.
 
But if I blow air over them, won't all the dust go underneath the fans to where the core hardware is?

Also, doesn't it have three fans? I only counted two.
 
Can you kinda angle it to blow back out again? I've only done it on the first two versions of the G5 iMac. The third version is slightly different.
 
mad jew said:
Can you kinda angle it to blow back out again? I've only done it on the first two versions of the G5 iMac. The third version is slightly different.
Click to expand...

Oh, I have the second revision. Do the Intels have three fans?
 
mad jew said:
I haven't opened an Intel iMac. I've got the same type as you and I always thought there were two fans, but I really could be wrong. Have you seen this?
Click to expand...

That's very interesting. Too bad they hadn't all shown them from the rear.

I remember reading that there were three fans in the G5's (rev. 1 + 2): one for the hard disk (shown), one for the optical disk (shown), and one for the G5. I could me wrong, too. When I tried to install my RAM, the G5 was amazingly hot!

Which reminds me of another thing. I got some RAM for my iMacs G3 and G5 today from OWC, and I tried installing them, but I couldn't fit the notches into the sticks. They were either right above or below the slots for them. I fit them in as much as I could with the gold part going in. What am I doing wrong?
 
I can confirm, iMac G5s have 3 fans.

You have the ALS revision, right? Would you mind posting your specs? ...My 1.8 GHz G5, 512 RAM, w/ Combo drive iMac's fans are very loud compared to my other iMac G5 ALS with 2.0 GHz, 1 GB RAM, w/ Super drive. According to Apple it's "normal," but I find that very hard to believe.

Could you try to explain your fan issue as detailed as possible? It would really help me out. For a comparison, I posted my problem in this thread.
 
About the RAM...

Have you installed RAM before? (Many people installing RAM for the first time are surprised how hard it is to insert the sticks).
 
iMacZealot said:
No, and No. I've installed an Airport card in the G3 before, which was extremely hard, but how do you properly install RAM?
Click to expand...
Have you read through the manual? ...That's how you install it, but the trick is, it can take more force than seems safe (usually first-time RAM installers are trying to be very cautious and gentle, and just don't use enough strength the push the sticks into the slot). ...But please, still be careful. ;)

You mentioned the slots don't seem to match up? ...They definitely should.
Obvious Warning: If the notches don't align, do not force them in (duh)!​


I would give it a second try, and if you still have problems, just let us know.
 
I'm really having problems with the G3 because my hands can barely fit through the opening. I took out the original stick to see how it was inserted, and I can't get it back in, so, I'm going to the Genius Bar. I think they maay have sent me the wrong G3 stick because it looks the same as the one I've been using, only about a quarter of an inch shorter.
 
iMacZealot said:
I opened my iMac G5 today to install some RAM....I couldn't get the stick in, but I'll fix that. What I noticed was the fans, and they were incredibly dusty. Could this be why my iMac sounds like an A380? If I clean them, will it be better? How do I clean them without seriously damaging something?

Thanks.
Click to expand...

To clean dust off the machine, I frequently use a Shop Vac with a bristle attachment at work. Shut the machine down first before you go vacuuming anything. I don't like using compressed air because it won't get rid of as much dust as a Shop Vac would, as you're still blowing dust inside the machine. You won't damage any components with the bristle attachment as long as you don't use force.

As for the RAM, examine both the stick of RAM and the RAM slot. There should be a notch on the stick of RAM, and there should be a piece on the RAM slot that would correspond with the notch on the stick of RAM. Examine this in a well lit area. Hold the stick of RAM up to the RAM slot and double check to make sure you have the RAM oriented the correct way. Make sure you have the locking tabs on both sides of the RAM slot opened all the way, and then insert the stick of RAM until the locking tabs lock in the closed position. You may have to push the locking tabs slightly, most RAM slot's locking tabs don't go to the completely locked position when inserting RAM.

Whatever you do, use extreme caution and don't FORCE anything. Otherwise you'll force yourself into buying a new Mac.
 
It will take some effort to install RAM, but you shouldn't feel that you are forcing it in. To discern between them, effort means you might have RAM-like indents on your thumbs, whereas forcing looks like the RAM slots are being bent off of the motherboard.

If this is what your iMac looks like (I believe yours is the Ambient Light Sensor Model, not the iSight), then look at this page, more specifically the bottom left picture. Notice how the black chips on the RAM stick are faced inwards toward the motherboard.

http://www.kodawarisan.com/imacg5/imacg503.html
 
So, I went to the Genius Bar and found my problem. I didn't realise that you push the stick in hard enough so that the notches automatically snap in. I was just placing the stick in gently and then pushing the notches back to place. At least I know how to do it now!
 
You should NEVER use a vacuum to clean the inside or outside of a computer.

A plastic hose with air sucking up it is a simple Van de Graaff generator, and the typical vacuum cleaner hose can easily generate voltages in the high 500KeV area.

Do you want a 500KeV potential difference anywhere near your mac?
 
500KeV discharging through ground through, say, the metal surround to a DVI port or similar can be just as damaging as discharges inside the case. This is actually more of a problem with the plastic-cased macs than with metal cases, because the charge has a time to build up and the only places to discharge are the ports/connectors.

It doesn't matter that the current is very low. This is why we take such careful static precautions when handling ESD devices, where as low as 5 eV discharges can be fatal to a component.

Someone also asked about using WD40 to clean the fan blades (in an IM to me). This is not recommended because the blade is left with a slightly sticky covering that traps dust, which is then much harder to remove. For the same reason, never oil a printer with a wet lubricant.
 
If I understand correctly:
- The fans are dirty.
- You want to clean them.
- You don't won't to blow them with compressed air because you want the dirt to exit the computer.
- You don't want to run a vacuum inside the computer, because the vacuum could damage the computer.

So, why not:
Remove the fans from the computer. Vacuum them. Put them back into the computer.
 
timswim78 said:
If I understand correctly:
- The fans are dirty.
- You want to clean them.
- You don't won't to blow them with compressed air because you want the dirt to exit the computer.
- You don't want to run a vacuum inside the computer, because the vacuum could damage the computer.

So, why not:
Remove the fans from the computer. Vacuum them. Put them back into the computer.
Click to expand...

I would imagine that if the fans could be easily removed, it would also be easy to angle the compressed air enough to blow the dirt and dust out of the computer. I've yet to open my imac though, so I don't really know.
 
KingofAwesome said:
I would imagine that if the fans could be easily removed, it would also be easy to angle the compressed air enough to blow the dirt and dust out of the computer. I've yet to open my imac though, so I don't really know.
Click to expand...

It's easy to open and get to the fans. You might need a T-8 screwdriver, which you can get for $3 or $4 at a hardware store.
http://manuals.info.apple.com/en/imacG5_17inch_UpperFans.pdf
http://manuals.info.apple.com/en/imacg5_17inch_LowerFan.pdf
 
KingofAwesome said:
I would imagine that if the fans could be easily removed, it would also be easy to angle the compressed air enough to blow the dirt and dust out of the computer. I've yet to open my imac though, so I don't really know.
Click to expand...

OK, I took apart my iMac G5 (ALS, Ambient Light Sensor) after work today. It was a super-easy process, and removing the fans to vacuum them was a breeze. I would suggest removing the lower fan completely, so that you can get the duct work clean. You could use compressed air on the upper fans, but I prefer to take them out and vacuum them, since it is a matter of turning 4 screws.
 
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