[rr44142]

Hi everyone,

First, thank you for reading this. I really appreciate any help I can get at this point.

Last night, I tried to install a new hard drive on my G4 MDD 1ghz, but silly me, I tried to put a 160gig drive into the wrong ATA controller, the one that can't handle such a big drive. So I pulled it out, rebooted, and everything was fine. I shut it down for the night.

Today, when I tried to boot up, the machine powered on and made some normal noises... but nothing happened, the screens stayed blank. After maybe 10 seconds, a very powerful and loud fan kicked in like crazy -- a person in another room heard it and thought it was a vaccum cleaner.

It does not chime or beep at all. No video is displayed.

And that is pretty much how things stand. I can turn it on and it comes alive with the fan kicking in hard after 10 seconds, but no display activity. However, the power button on the ADC display still will turn on or off the machine.

I tried turning off the machine and taking out the CMOS battery, and I tried resetting the PMU by holding in the reset button for a couple seconds and then leaving it unplugged for a while. After I tried that, they power button lit but it did not power on until I hit the PMU reset switch again. Now it powers on again, but just does the same thing as before -- nothing except run the fan. Is that the proper way to reseat the PMU?

I've take out the ram, all PCI cards and the AGP video card, that doesn't help. I'll try reseating the hard drive next. I'm scared to reseat the CPU -- I've never done that before and don't know how.

Can anyone tell me what I should try next to reach a diagnosis? Thank you so much. I really appreciate it.

PS - Some more info. Right after I turn it on, there is a kind of weak thudding noise from the hard drive or power supply area, not sure how to describe it. Whunnnh, whunnnh. Happens twice then stops. And the red light on the motherboard next to the ram is always lit.

[bgordon]

Have you tried booting from the OS X CD? If you can, put it in the CD drive and press "C" upon startup (you prob already know this and may have already tried it.) If it works, it will at least give you an indication of how screwed up your machine is.

You've reset the PMU....hmmm....when you were swapping hard drives, did you change the jumper settings at all on your original boot-up hard drive, the one with OS X on it? I've had some jumper craziness of my own in the past, system wouldn't boot because I'd swapped jumpers around....

I know those are pretty obvious, but they're the only ones I can think of. Good luck.

- bgordon

[rr44142]

You know, I didn't even try a CD, because it doesn't chime or power on the display or anything. I did try a firewire drive -- no luck.

OK -- tried a CD. Nothing.

I did not switch around the jumpers. I'll admit, though, that I did plug and unplug the power from the secondary drive while the machine was on. I always used to treat IDE drivers as pretty much hot swappable. I mean, I know they aren't but I always said eh what the hell. No more!