You can fix yourself by replacing the capacitor. Here are some functionality symptoms and issues. Your system might display if your capacitors are failing.
The computer only turns on sometimes or not at all.
The computer fans are on high speed all of the time.
The computer turns off unexpectedly.
The computer gets extremely hot.
The computer turns on but the screen remains dark.
The computer has random colors on the screen.
The computer crashes or becomes unresponsive.
The computer keeps going into sleep mode for no reason.
Any of these symptoms ?.
You have any of the above symptoms on your iMac G5 it is most. Likely the capacitors are bad. Don't pay hundreds
of dollars to get it Fixed when you can do it yourself.
Checking those caps is easy and takes 2 minutes:
Power Supply Symptoms:
Check the LED lights on you computers logic board (check the capacitors too)
#1 if the first LED light is not on you power supply is bad (not working)
if the first LED is on but the computers is Not (no video) and the computer fans are on high speed You Logic Board is Bad
computer only turns on sometimes or not at all.
Plug the power supply back in and check the diagnostics lights on the logic board.
LED 1 indicates that trickle voltage from the power supply has been detected. This LED will be ON when the computer is turned off and your power supply is working correctly.
LED 2 indicates that the main logic board has detected proper power from the power supply when the computer is turned on. Th
is LED will be ON when the computer is turned on and the power supply is working correctly.
LED 3 indicates that the computer and the LCD display are communicating. This LED will be ON when the computer is turned on and video signal is being generated.
LED 4 lights only if the computer detects an over-temperature condition. This LED will be OFF when the computer is turned on and running at the correct temperature.