The PowerMac G5 is a desktop computer first produced in 2003 by the Apple Corporation. This guide will review the repair process of an Apple PowerMac G5 model number A1047 EMC 2061 from 2004. It was discontinued in 2006 as part of the Intel switch first to developers then consumers.

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Unique Not powering On Issue?

Good day!

I recently bought an old G5 Powermac Dual 2.0Ghz along with a 23" Cinema Display. Model is an A1047, EMC 1969, PowerMac 7,2, made June 2003-June 2004; all based on the Serial lookup on everymac:

Aftermarket ad-ons, which were already installed:

  • There is an aftermarket ATI Radeon 9800Pro 256mb Graphics Card installed. The GPU fan does spin.
  • There is 1.5GB of RAM (6x256MB).
  • It did NOT come with a hard drive, but I do have 2 working hard drives which I installed to see if I could get it to boot. One with 10.5, and one with 10.0 (although, I realize that everymac says 10.2 is the lowest it came with).

I have done research and haven't been able to find anything based on my specific problem(s):

  • First, and this is the weirdest based on not being able to find anything about it….when power it on the LED light turned on as the button is press; however, as soon as I remove my finger the LED turns off - yet the machine is still running. Anytime after removing my finger from the power button (meaning that the LED is off while the machine is on) if I press the button the light will turn on, and as soon as I remove my finger from the button the LED power light turns right back off (but not the machine).
  • There is NO chime.
  • The fans ARE running.
  • If I leave it running for about 1-2 mins the funs begin to spin very fast…it sounds like an aircraft! lol
  • There is NO display to the, Cinema display, which DOES work as tested through the ADC to DVI adapter to my other Mac.
  • Various, and working, USB keyboards and mice do not work. Caps lock will not light up, and the mice have no optical lighting underneath. Also, the eject button on the keyboard doesn't do anything.

What I have tried, based on other articles:

  • Power supply does click when plugged in, read in the Apple manual that good ones often do that.
  • Swapping the positions of the CPUs.
  • Running only 1 CPU on the #1 (top) CPU slot; tried with both CPUs.
  • Reseating the RAM.
  • Using different combinations of the RAM (however using the same amounts, same locations on both sides).
  • Removing the graphics card to see if the boot up chime will happen (read that can be a way to test if it is bad, when you don’t have an extra GC laying around).
  • I was able to use a paperclip to open the DVD drive, and it does closed by itself when you push the tray.
  • Replaced the PRAM battery.
  • Tried resetting the SMU by pressing the SMU reset button on the logic board.
  • Ensured the CPUs were seated correctly.
  • Capacitors look good

Note, that in all of the various combinations mentioned, the power LED light does not stay on unless the power button itself is being pressed.

What are some of your thoughts here? I feel that testing the logic board and individual CPUs with ones known to work would be the next best approach; however, before going out and buying anything I thought I would see what others thought!

Hopefully, this can help someone else too!

Thank you for any help you may provide! :)

Answered! View the answer I have this problem too

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Chosen Solution

Locate and press the CUDA button on the logic board and let me know if anything changes.

Remove the 10.0 drive for now. It's best to try to take a machine back to the original configuration when diagnosing. Replace the PRAM battery.

Power Mac G5 PRAM Battery Replacement


here's where to go next:

Here's what Apple will tell you on the 7 LEDs:

Now here's where to find what they really mean:

Page 139 of the Service Source Manual

Power Mac G5 (Late 2005) Troubleshooting — General Information14 0 Diagnostic LED Table LE

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Thank you very much for your help, Mayer! I have seen several of your posts on other topics before I created this account (which I did today), and wanted to say thank you for those as well!! :)

* I just tried the CUDA button (again) with no avail. It is still turning on, while at the same time no chime, no video, no USB interfaces, and the LED at the power button is OFF (while the machine is ON), fan still spin slow for the first couple of minutes before Sulu sends them to warp!

* I did remove the 10.0 hard drive as well.

* I also just tested the PRAM battery (which was just replaced), and it measures at 3.6V.

Would you happen to have any other ideas/suggestions??


Thank you for the update!! That is a great manual!

I was looking through the manual and found some ideas that are very close, staring on page 144 "System Failures".

The closet one I have found is, "Power-on LED illuminates when pressed in, but goes out when button is released,there is no boot tone or video, but you can hear a small click"; however, there is no *click* occurring, as the system and fans are turning on.

I am thinking that I will go through the various ideas under "System Failures" like trying a new video card, new front panel board, then processors, logic board...maybe I'll get lucky and it will be something simple!

What are you thoughts?

And, thank you again for everything!! :)


The two things (in order) that I have seen fail on this model the most are, the video card, the PSU.

This is the card I use most to replace with:

GeForce GT 120


Thank you very much! It will be a few weeks before I can buy a replacement video card. After I do I will let you know how it goes! :)


@efitz Do a new PRAM battery first. It's a 1/2 AA 3.6 volt. You should be able to get one for about $6.00


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