Question about Apple iMac G5 Desktop
The computer won't turn on. the power cord is good. Any suggestions?
It's probably burned-out electrolytic capacitors in the power supply section or on the logic board (to other technicians on this board, yes they do burn out - cut one apart and you'll see the paper around the plus lead is turned to charcoal). Those are relatively low-cost components ($0.40 - $1.60, depending on the size), but require technical expertise to replace (ability to change parts on multi-layer boards with lead-free solder, and observe electrostatic discharge precautions to prevent damaging the board). Burned-out electrolytic capacitors are often readily identified by visual inspection - the tops will be bulged out and often have material leaking from the vent. In the photo below, a bad capacitor is shown next to several good ones.
If this is the case, insist that your repair technician select new capacitors for high ripple current and endurance (at least 8000 hr. rating) as well as the same or better temperature rating. I've found the Panasonic FR1 series capacitors work well for this application. United Chemi-con's EKZN series should also be adequate. They may cost a few nickels more than other brands, but the money is well worth spending.
Posted on Nov 30, 2014
It could be the internal PSU that has failed. Take it to a Mac repairer.
Posted on Nov 25, 2014
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Posted on Jan 02, 2017
Is this a tower or Imac?
Is there a reason other then curiosity you need to know?
All power supplies have it labeled on them what they are if you need it.
Posted on May 05, 2008
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.
Posted on Jan 05, 2009
SOURCE: iMac G5
If it isn't the power supply, some of the early G5 imacs had a capacitor failure issue...mine just died, in fact. It was just shutting off by itself, even turned on once by itself....but tonight, when it shut down, it would not restart. I opened it up and looked and sure enough, 11 bulging/leaking capacitors. My local service center says there are two options: 1. new mother board-aprox $500 or replacing the capacitors- between $170-200. Until Dec 15, 2008..this was apparently covered under a special warranty extension program Apple had....typical!
Posted on Mar 07, 2009
Assuming you have the model with four diagnostic LEDs, the lack of LED-3 indicates that the computer and the LCD display are NOT communicating. This
LED should be ON when the computer is turned on and video signal is being generated.
The first solution is to reset the PRAM (hold command-option-P-R after the boot chime until you hear another boot chime). If video does not appear, then power down the computer and reset the SMU by pressing the SMU button ONCE ONLY. (The SMU button is located just south of the fan housing and is the button further away from the fan; the other button is a power button.) If this does not fix the video, the next step is to remove the optical drive. If this does not fix the video, put everything back together and attach an external display using the dongle supplied with the unit. If the external display fails to work, you have a logic board problem; otherwise, you have an LCD panel, inverter, or cable problem.
Posted on Apr 02, 2010
try to start up the computer without any cable connected on it, maybe the keyboard is making the problem, or the mouse too
Posted on Aug 12, 2010
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