Computer will try to start. Power light comes on and chimes, but nothing else.
iMac G5
Hard to diagnose without seeing it. Could be the main motherboard, or the power supply.
You need to take it to an authorised service provider, but not an Apple Centre as they will not/cannot assist with an long obsolete model.
Often what has happened is the PRAM battery is low. After 4 years, especially if the computer is left unplugged for a lengthy time period, the PRAM battery needs replacing. It is a coin shaped battery inside the machine. If you replace it yourself, be sure to take static electricity precautions by touching the plugged in but off power supply before you touch with the same hand you use to access the logic board. If it still doesn't power up, the red lights on the logic board should say what is wrong. See this article:
iMac G5: Troubleshooting when there's no picture on the display - Apple Support
https://www.macservice.com/imac.html does logicboard replacements.
Apple G5 Hardware . . . Computer chimes and front power light comes on, that is it.?
