Have an elderly G4 733Mhz (Quicksilver) that's refusing to startup - press the power button which lights up whilst it's pressed but nothing happens and it goes out as soon as it's released...

Not seen anything like this before - anyone any ideas?

Well, would you believe it. Came in this morning all ready to open it up and reset the PMU and just to check, pressed the power button. The little monster turned on as if nothing was wrong!

Going to replace this machine now as it's in an important area of our production cycle and I'm not going to take the chance that it'll do that on a production day!

wierd
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expertise: nothing

Never underestimate the power of ghosts in the machine. One thing I have noticed and do now is open up my computer and remove the dusts that collects in there. You wouldn't think that much gets in, but it does. Also, if something like this happpens again, open her up and reconnect some of the cables. I had one where I just reconnected everything, and boom, all was working well again.

Many years ago I worked for a big UK book publisher with about 1000 Macs and had a couple of spooky machines in my direct area of responsibility.
1 was a flatbed scanner that wouldn't work properly for 24 hours after having been moved by more than 1" in any direction.
The other was a Mac IIsi that kept crashing twice a day with the same error. Replaced EVERYTHING inside this machine to sort the problem out, both software and hardware to no effect. In desperation I swapped the plastic top cover of the machine with another IIsi. The Mac behaved itself from then on.

ffistometer,

I want to say it sounds like the pram battery maybe dying in it. That is one of the symptoms, is that when you power it on and it goes back off. It has something to do with pram, since it can't keep the settings it won't let it turn back on. (Doesn't always happen like that, but its worth a shot.) - TPD

Hi ...Dude

Yeah, twas the next thing to try after PMU reset (clock/date came up fine when I did get it to reboot) but it was a suspicion as it's a late summer 01 built Mac (Serial CK129... Built in Cork week 29 of 2001) so about 6 years would be expecting the battery to start giving problems.

Managed to get its data Migration Assitant'd over to a replacement machine of a lesser vintage so this Quicksilver is currently pushing up the electronic daisies!