PowerMac G4 (Mirror Doors) won't startup

Try everything in Texas Mac Mans tutorial including what to do if all else fails.

Cheers!
DALE

I don't know. have you booted up on and run your Apple Hardware Test disk to see if it flags anything?

Cheers!
DALE

I understadn you have tried advice in 'all the other posts' but that can cover a lot of ground, so to be a bit more specific....

Do you hear the HD spin up?
Have you added any hardware recently?

Although you have tested the voltage on the power supply, have you also checked the individual cables going to both the MB and the HD?

If you have 3rd party cards, USB hubs, etc, remove them, then do the PMU resets, etc)

Since you have been inside the machine, verify all connectors, ram, et al are firmly seated, and the cables are not cut or insulation scraped away.

If you have anything in the front drive bays, make sure the ribbon cable is not pinched or cut. (that happened on mine, grounded out the system, and had the same problem you are now experiencing - new ribbon cable fixed it.)

dotfoil,

As suggested check the connections of the drives, remove any pci cards, go back to the stock configuration as much as possible.

That said, when my mdd did what yours is doing it was a motherboard. Does it chime at all? Do any of the drives spin up as AJ said?

Earlier today I saw a post on corrupted nvram that was fixed by removing power and the battery, plugging in, powering up without the battery, then putting the battery back in. It is easy enough to do and cost nothing (unlike a motherboard).

Resetting nvram from Open Firmware will take care of any corruption to nvram, rebuild the device tree, but a Mac that won't boot, won't let you get into OF. so the PMU + battery and unplugging from the mains has to be done, and then, I would also add the reset-nvram to the routine.

A corrupt directory, if severe enough, will keep a system from booting from CD or from the hard drive as well. In which case it can be necessary to unplug the drives and try with your OS X install CD/DVD.

Doesn't resetting the pmu also reset the nvram?

That is my impression on reading from the Apple docs.

Yes

How can he run AHT if his Mac won't turn on?

I have the exact same problem anyone got a solution?

ryan42,
He he he. Boy I sure blew that one! Yes, bootup on a CD with a Mac that won't powerup! Ooops
DALE

Chilly,
Try everything in the tutorial I linked for dotfoil, 2nd post down.

Cheers!
DALE

Have done so, several times, sometimes I get power to the fans and l.e.d. on the Logic board light. other times nothing at all, but still no startup chime!!!

What PCI cards are installed in the machine?