Noisy 'ol imac

June 26, 2009 2:21 PM

iMac filter: 1st generation flat screen imac. Internal fan whirring constantly & loudly (1.6GHZ powerPC G5). I just maxed the memory from 256 to 2GB. I thought this might help. It's working much faster (thankfully) but the whirring is relentless. Last resort is to purchase a new one...I'd rather not go this route for now. FTR she has been doing this for quite sometime, so not a recent activity. Any suggestions on how I can silence my old lady?
posted by sequin to computers & internet (10 comments total)

ol' that is
posted by sequin at 2:23 PM on June 26

Might the heatsink or vents be clogged, raising temps so the fan runs harder?

Otherwise you may have to replace the Fan.

Also some apple systems do glitch and run the fan 100% for no reason, the solution is sometimes a firmware update, even on systems that showed no dymptoms for years.
posted by Rendus at 2:28 PM on June 26

This is very common with old G5 iMacs. Unfortunately it's usually followed by imminent failure.

You should plan on it not being alive for long.
posted by Mwongozi at 2:35 PM on June 26

If you haven't already, Google for "iMac G5 fan noise". See the 566,000 results? You are not alone.

I'd suggest startign with the obvious: check to make sure the air inlet isn't clogged with dust.

Next, you might want to try resetting the power management unit (PMU). This hint explains how to do that on a 2004 model, but you should Google the procedure for your specific generation/processor iMac G5.
posted by mosk at 2:58 PM on June 26

Just thought I'd point out that adding memory increases power consumption. Adding memory is good for a lot of reasons, but it doesn't make the machine run cooler. (Except that it can reduce HD activity somewhat.)
posted by Chocolate Pickle at 3:01 PM on June 26

Adding memory increases power consumption the same way turning on your headlights increases fuel consumption. It's not significant enough to affect anything.
posted by ryanrs at 4:18 PM on June 26

Further to mosk's comment if resetting the PMU doesn't fix it AND the noise starts immediately when you power it on it can only be one of two things: firmware or hardware. Use the software update tool to verify you haven't missed any firmware updates, and if there aren't any or it doesn't go away, you're looking at needing a repair.

If it takes a while to begin making a racket it's a whole different ballgame and a lot more complicated.
posted by fearnothing at 4:41 PM on June 26

Back up your data today.

It might be some low-level power management / similar wonkiness. Reset your SMU and PRAM. Run Software Update from the Apple menu to make sure you haven't missed any Firmware or other relevant updates.

If that doesn't work, it wouldn't hurt to clean it out. This is unlikely to resolve it, but hey; worth a shot, right? You already opened it when you put the RAM in. Open it carefully and use compressed air to blow dust/debris out, especially around the fans and intakes.

If it's not resolved by those two things (sorry to be pessimistic, but it probably won't be resolved by those two things), you've likely got one of two issues:
1: Faulty temperature sensor; fans are running too high although system is not in fact running too hot. Temperature sensor is part of the main logic board, which will be several hundred dollars to replace.
2: Unit is actually running too hot. These G5 iMacs are notorious in service departments for blowing caps on their power supplies and/or logic boards -- there's a decent likelihood that this is what you're looking at. Enterprising individuals with soldering skill have individually replaced blown capacitors, but I would recommend against it. A new power supply is not cheap, either. In most cases, you're better off replacing the computer when it ultimately fails, and migrating your data from the data backup that you definitely already did today.
posted by churl at 4:46 PM on June 26

It's probably just a bit of dirt, but obviously anything that hampers cooling isn't good. Every PC I had needed cleaning every year or so, fans tended to wear out after 2-3 years, and I'm sure the iMac I'm typing this on contains a fair bit of dust as the fan noise is a little louder.

If you're not happy opening it up and poking about yourself, find a local repair shop that'll replace the fans and clean it out without charging too much.
posted by malevolent at 5:48 AM on June 27

Exactly what churl said. My iMac always ran loud, with the fan whirring when I'd do something processor-intensive, but it got a lot more frequent in the six months before it finally died. We took off the back and there are several blown capacitors. My Linux nerd husband also thinks the power supply smells fried. I've investigated repair options (both DIY and professional) and it's prohibitively expensive. Right now it's just sitting in my office, a very expensive paperweight. (That said, the hard drive was fine so we just pulled it out, put it in an enclosure, and got all my data off that way. So if yours is doing the same thing, you won't necessarily lose all your data.)

Sidenote: Anybody want to buy a dead iMac?
posted by web-goddess at 7:40 PM on June 28