Last night my G4 MDD suddenly started making weird noises. The best I can describe it is a loud tick-tock noise with a vibrating metal noise over the top. It lasted several minutes then suddenly stopped then about 30 minutes later it suddenly started making the same noises again for a minute or so. Today however its perfectly fine.

Is this normal and can anyone tell me what it means?

Could be a fan making that noise.

Had similar noises with a fan in a PSU on a Digital Audio.

That is either the PSU fan or the case fan starting to die -- it's bearing is giving out and the blades have become un-balanced.

The case fan is usually the culprit, though, because of the way it is installed -- airflow into the fan is only available from the lower third of the intake-space, which results in unwanted torque on the fan. If the intake grill is clogged with fluff, or the fan blades are caked with gunk, this will make the problem much worse.

I think you may be right as this is 'exactly' what happened with an older Quicksilver I have. I'll have a proper look over the weekend and see if I can see any problem with the main fan. However it seems to be going fine today with no hint of any fan problems - well no noise anyway.

I've had a funny sound come from my digital audio too, I guess it's the fan. I've got a dead B&W G3 that i've recently gutted out for an arts project and kept the parts, would the fan from there still be of any use to replace?

You mean use the fan from the B&W to replace the noisy one from the DA? I'd first suggest just buying a new one ($5-$10) instead of replacing an old fan with an even older fan. If you really don't feel like spending the money then pulling off the dust seal/label and adding a tiny drop of oil/vaseline (or other light grease) to the bearing can make a dramatic difference in old, partly siezed/stiff noisy fans.

I don't think the issue with my MDD is a simple fan issue as each time this happens the computer simultaniously experiences a kernal panic. Now if this were a case of a loose bearing causing the blades to become slightly unbalanced (and causing a rapid tick-tock sound) then It would be a mechanical only problem and as such the OS should be unaffected. Correct?

There's also a possibility that the tick-tock sound is coming from an HD. Recently, one of my Western Digital HDs blew out in my Mac Pro. Before it completely stopped working, it made a kind of solenoid noise as if it were switching on and off.

That could account for your KP'ing if it's happening to the boot drive.

Dave

Ahhh, didn't know about the KP -- I agree with macdave, noise + KP = dying hard drive.

Yeh my partner's old PC had a HD that went tick-tock then kaput. macdave - I agree

Thanks for that, i'll try it when I get the time to use the mac.

I might give the Apple tech people a call and see if they think a dying HD could account for the rapid tick-tock sound with kernal panic (well I get the spinning beachball of death and the system becomes non responsive during the tick-tock and only after the tick-tock stops does the system recover). Though I've had no issues writing to the HD and TechTool Deluxe reports no problems.

DA, I had that exact problem with my G4 last year -- the machine would lock up (every app would give me a beachball) and there was this ticka-ticka-ticka, ticka-ticka-ticka noise. I forced a shut down, restarted, and everything behaved itself for another couple of weeks, then it happened again.

The culprit was a Seagate 120 GB hard drive -- for some reason, it had lost the plot and was trying to find track zero. The ticka-ticka noise was the sound of the heads seeking from one end of the disk to the other over and over.

I replaced the hard drive and everything has been running smoothly since. I still have the misbehaving hard drive, and I use it in an external drop-in cradle for when I want to shift a large amount of data from one machine to another where networking isn't feasible (such as from one house to another). it hasn't failed completely -- yet -- but I don't trust it

Ok I've found the information pertaining to the 'EXACT' problem I'm experiencing. The discussion is at Apple - Support - Discussions - Clicking sound - freeze - HD failure? ...