iMac G5 Not Booting Properly

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baxter146 Author

Level 1

8 points

iMac G5 Not Booting Properly

I factory reset my G5 awhile ago and when i came back to it today and tried to boot it, there was:

- Black screen

- Chime

- LED was on (not flashing)

So I restarted the iMac and held down:

Command + S

then i typed:

sh /ect/rc

(because the terminal said that if i want to boot into single user mode, I should type that)

and clicked enter

The terminal then said “Checking Disc”

I thought I did the wrong thing and in a moment of panic, shutdown the system by holding the power button for 5 seconds.

Now when I try and boot the iMac:

- LED lights up and doesn’t go away

- No Chime sound

- Black screen

- Fans go really loud after 2 minutes

Keyboard does absolutely nothing, doesn’t take CDs, nothing.

Can i fix it or have i messed up this iMac G5 forever?

iMac Line (2012 and Later)

Posted on Sep 4, 2020 11:10 PM

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Answer 1

baxter146 Author

Level 1

8 points

Sep 6, 2020 5:41 AM in response to HWTech

I followed the steps you mentioned with no success, just the same issue as before.

I did however open the back of the G5 and found nothing out of place or broken. (Pictured below)

I also tried taking out the RAM and putting it back in but that didn’t fix it.

I’m convinced it’s a software issue not a hardware issue because of the way it stopped working.

Is there anything else I can try?

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Answer 2

baxter146 Author

Level 1

8 points

Sep 7, 2020 3:49 AM in response to HWTech

The LEDs don’t indicate anything wrong. (at least that’s what I think).

I plugged the computer in:

First LED green
Other LEDs off

Turned on the computer:

First and Second LEDs green
Other LEDs off

Here are some pictures

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Answer 3

HWTech

Level 9

60,302 points

Sep 5, 2020 12:03 PM in response to baxter146

Unplug the G5, then press & hold the power button in for 10 seconds. Wait 10 seconds, then plug in the G5.

Power on the G5 and perform a PRAM reset (hold the PRAM reset for at least three chimes or a full minute).

If you don't hear the chimes during the PRAM reset, then you have a hardware failure most likely with a bad Logic Board. The Logic Boards on the iMac G5 had known issues with bulging capacitors (as did the power supplies). My guess is if you remove the back cover of the iMac you will see some of the tall capacitors are leaking or the tops are swollen (rounded) like those seen in the picture on this page:

https://elitemactechs.com/wp-content/uploads/2017/02/iMac-G5-Capacitor-Swelling-1024x768.jpeg

The brown spots are the internal chemicals leaking out the top of the capacitors. The capacitors are the tall cylindrical components that are most prominent in the photo. I see 5 capacitors with the brown spots on top of them. I also see two other capacitors in the photo that have the bulging or rounded tops to them, but don't have any of the brown spots yet (top one in the first left-most column and the bottom one in the second column).

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Answer 4

HWTech

Level 9

60,302 points

Sep 6, 2020 12:46 PM in response to baxter146

With the back cover removed, plug in the AC Cord and power on the computer. What is the status of the four diagnostic LEDs located at the top center of the Logic Board just below the center fan?

Be careful not to have any metallic or conductive objects touch the inside of the computer while it is plugged in to the AC cord.

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Answer 5

HWTech

Level 9

60,302 points

Sep 7, 2020 7:42 AM in response to baxter146

LED #3 should be lit. When LED #3 is not lit, then it indicates the Logic Board is not communicating with the LCD Panel. It is common for the LCD Panel on these white iMacs to fail, but there is no guarantee that the LCD Panel is the part that is defective. The Logic Board could be defective, or the Power Supply may be defective since the power supply in the iMac G5 is also known to have bad capacitors. Unless you can use the iMac with an external display, then I would say it is time to recycle this iMac.

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Answer 6

baxter146 Author

Level 1

8 points

Sep 6, 2020 4:25 PM in response to HWTech

How do I power on the iMac G5 with the back plate off?

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Answer 7

HWTech

Level 9

60,302 points

Sep 6, 2020 7:37 PM in response to baxter146

You use a flat blade screwdriver to short the two pins where you disconnected the power button from the iMac.

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