I just bought a "Yikes" G4. Price was the issue or I would have bought something newer. I bought it from BetaMacs. The problem is that in about 1 or 2 out of 20 boots it just shuts down after 5-10 seconds. I have replaced the mobo battery, zapped the PRAM, booted from an install disk and run Disk First Aid, and finally wiped the disk and did a clean install of OS X 10.3
It still happens. Am I looking at the beginning of a Power Supply failure? Is there something I've missed and not checked?
I've priced Power Supplies and they cost more than I paid for the computer.
Unless I can resolve this soon I will have to return it under the 30 day warantee.
Any help appreciated.
Is it an eMac? That's one of the big symptoms of the infamous logic board problems they recalled for.
If it's not an that easy, you may need to provide more information about your system for people to diagnose.