Apple iMac 17 Model A1058 won't turn on.

ebay, amazon, apple, etc....

Never heard of before, though power there.

Guess, try holding the on/of switch in a little longer, some systems act as reboot/reinstall

Hi Joseph,

Well it's a 9 year old iMac.. it sounds to me like the power supply has failed. Nothing under $300 to fix unfortunately

I have minor shutdown problem with mail, won't close or shut down. My ans top left APPLE drop down, force closure, turn of each programme listed. For me works a treat.

Are both of the RAM 1GB, and did you make sure you bought the type of RAM that works for your computer?

Bad capacitors often cause the no-turn-on problem. This page has a good picture of what bad caps look like in the G5. If you see this trouble in your G5, you might be able to get this going. Kits of capacitors are available (here's the place I got some from) and If you're comfortable with electronic soldering and replacing parts on a printed circuit board, changing out the duds may be all that's needed. I've seen three of these now. On one, there was just a single bad cap that was keeping the computer from starting up. It's certainly worth looking into.

If someone has looked at this issue and determined it to be a logic board problem then the only solution is to replace the entire logic board.

You can purchase them on usedmac.com here for $289:
http://www.usedmac.com/catalog/product_info.php?cPath=34_160&products_id=2384&osCsid=555099ea1dd6e69fa573fbc345fbe149

Here are instructions on replacing the logic board yourself:
http://www.ifixit.com/Guide/Repair/Installing-iMac-G5-17-Inch-Model-A1058-Logic-Board/971/1

Power supply or capacitors on the MB have gone out.

hmm may be a problem with it or the energy saving function is set, click the apple top left and go to system settings, if its not there, check on the task bar (gears picture) or in finder and it basically has the same standby settings as a windows pc

Re the light turning on for about 3 secs.
Does the computer make a 'start up' chime or any other tones?
If not, this could be for a variety or reasons.
Firstly you need to verify that the power supply is working. Remove all connections from the computer including the keyboard and mouse. Try to start up again. If the computer still fails to start up, you will need to gain access to the computers internals.
Lay the computer face down on a soft cloth to protect the screen. Undo the 3 silver screws on the lower edge of the computer. (one at each end and one central. These are captive screws.)
Lift the rear cover away from the main body of the computer.
On the Logic Board there are 4 diagnostic LEDs indicated by a yellow arrow on the board. To the left of these LEDs there is a small button. This allows you to power on the computer with the rear cover removed. Connect the power lead. LED1 should be 'ON'. If it is 'OFF' then you need to replace the power supply.
Turn the computer on by using the internal power button.(LEDs 2&3 should now be 'ON'. If LED2 only comes on momentarilty then replace the power supply).
Does the computer start up normally after pressing the internal power button?
- Yes: Press and hold the power button until the computer powers off.
• Unplug the power cord from the iMac, and reinstall the back cover.
• Return the computer to the upright position.
• Plug the computer back in, and press the power button to turn on the computer.
• Make sure the computer is starting up properly. If the computer will ONLY start up
from the internal power but will not power on from the power button on the back
cover, the power button on the back cover may be faulty.
- No: Reset the SMU.
• Unplug all cables from the computer, including the power cord.
• Wait 10 seconds.
• Plug in the power cord while simultaneously pressing and holding the power button
on the back of the computer.
• Let go of the power button.
• Press the power button once more to start up your iMac G5.
If the computer starts up normally then shut down and replace the rear cover.
If you feel uncomfortable about working on the computer, take it to a reputable repairer.
Hope this helps.