[bmizar]

I have a Powermac G4 Model # M5183 400MHz Desktop that is not powering up at all. When I push the power button on the front nothing happens. I have tried a new power supply, new power cord, different outlets. This all started after about 3 power outages in a couple days.

Is there anything else I can try?

[Sherman Homan]

Sounds bad. The button push activates a circuit on the motherboard. If you have put in good power supply and there is no response from the Mac, then you gotta suspect that the mobo flamed out in one of those outages.

[Waragainstsleep]

There is the long shot chance that the front panel board has failed. Do you get any lights on the board (even for a second)? If you do, its probably the board. What about any clicking noises?
If its completely dead, you don't see too many boards do that without some sign of damage. Inspect the board carefully for blown components or scorch marks. Powders or residues can also indicate component failure.
Reduce the system to bare minimum. Disconnect the drives, speakers, peripherals, fans, everything except front panel, logic, PSU, CPU and one stick of RAM. Reset the PMU and then plug in and see what happens. Disconnect everything from the logic board end.
I forget whether the programmer button does anything apart from firmware updates, but if there are any resets using that, I'd do those too.

[chris v]

I had a RAM slot go bad on a machine of that vintage once. It wouldn't boot at all until I pulled the RAM out of the bad slot. Try removing your RAM modules one as a time.

[reader50]

With the system off, locate the CUDA reset button on the motherboard. Press and hold this button for a few seconds. Not more than 10.

Then try the front power button again, see if it will power up.

[32rider32]

you could buy another pm g4 from me if you need a new one