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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Power Mac G5 Shuts-down A Few Seconds After Start-up

Hello to everyone

I've a problem with my powermac g5 DUALCORE, Shuts-down A Few Seconds After Start-up, I can't see nothing on the screen the shut-down time before the star up in short only 1 second, I think is not the power supply, CPU? I've tried to remove the cpu and power-on and the mac in on... Mac is on until I disconnect the power cable, hold down the power button to switch off does not work

Thank you so much

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mayer thanks for your interest maybe you're the only person who can help me, Mac is in its original state, no change of cpu or another, no flashing LEDs on the front panel, just turn it off after 1 second.

I bought this mac on ebay a few Euros just to use houses, the first time I turned it, the LED remains lit but no apple initial gong and no video signal, I spend and I turned back for the second time and has started well until the folder with question why but there was the operating system, then turned regularly and put in the box for a few days. Yesterday I wanted to install the operating system and has this problem, it turns off immediately, this is very strange, I do not think it's the power supply ....


nobody can help me for my problem?




I downloaded a technical manual for this g5, I checked all the power supply voltages, and it was all ok. I changed the CPU and Mac is a good start, now it's all right, never the cpu although he had no obvious damage was damaged.

I hope that this solution can autrare someone else.


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1 Answer

Chosen Solution

The first thing to do is to return it to as close to the original configuration as possible.

Next see what the diagnostics lights are telling you. Tearing into a machine without knowing what you are looking for is a very bad idea.

UPDATE 6/18/16

"Interpreting the LEDs"

"To interpret the LED indications, refer to the following table:"

"LED Indication On Off"

"1 Main logic board"

"detects trickle voltage from the power supply."

"iMac (24-inch) is con-"

"nected to a working AC power source. The LED will remain on even when the com- puter has been shut down or put to sleep."

"AC power source"

"is disconnected or power supply is faulty."

"2 Main logic board"

"detects proper power from the power supply when the computer is turned on."

"Computer is turned on"

"and power supply is working correctly."

"LED 2 will be off"

"when the computer is turned off or the power supply is working incorrectly."

"3 Communication exists"

"between computer and video card."

"Computer is communi-"

"cating properly with video card."

"If LEDs 1 and 2 are"

"on and you heard the startup sound, but LED 3 is off, video card may either be installed incorrectly or need replacement."

"4 Communication exists"

"between computer and LCD panel."

"Computer is turned on"

"and video signal"

"is being generated. If LED 4 is on and there is no display on panel, panel or"

"inverter may either be"

"installed incorrectly or need replacement."

"LED 4 will be off if"

"the computer is turned off or if no video signal is being generated."


"Computer has power"

"but no video signal."

"Computer is starting"

"up or display has entered sleep mode, turning off the video signal."

"The front LED will"

"pulse when the entire system has entered Energy Saver mode."

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Why remove the CPU and expect it to work ?


.... but certainly not the mac stays on and does not go out, I do not understand if the power supply or other fault what can be? I checked not cpu seems to be damaged.


I Will try to walk you through the diagnostic steps in a bit after I am fully awake. Part of the problem will be in not having its history. I want to have the book open in front of me so we can do this according to Apple's recommendations. Do you have the original system installation DVD? Do you know if it has been taken apart? Has RAM been added, what is the RAM configuration, does it have the original hard drive, have any drives been added?


I tried it in small steps.

I unplugged all the internal peripherals without any results

I tried with 1 gb ram without result

I tried to remove the whole ram without any results

Failed to start the diagnostic dvd because it just is turned off.

the only other thing that happens is when I remove the cpu, the mac stays on, until I remove the power cord, hold hold for 6 seconds 6 sec the ignition key does not need to turn it off, I have to remove the power cord.

seems to me a short circuit of some kind but do not know where to look, it is possible that both the power supply? in this case should have the same problem without the cpu mounted ... but this does not happen, it stays on.


First unaccept my answer until you have a solution. I need to find my book on this one, it's not a quick answer.


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