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Bericht: Antwoord op "Will not boot, grey screen"
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Kiezers: oldturkey03 (Door beheerder besloten)

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Will not boot, grey screen

This is a G5 2.5Ghz Quad. OS X 10.5.6. 8GB RAM. I get the boot sound, then a grey screen. That is all. Then the fans start blowing real loud until I turn it off.

This is what I have tried:

  • replace with other RAM
  • unplug drives
  • Reset nvram like in this article. The problem is then that I have problems getting to OpenFirmware. Sometimes I am able to but when I get to the OF screen there is no reaction from typing. I can i.ex. type the first line but then there is no response from the keyboard. The keyboard is plugged directly into the USB port.

*

I got hold of the Apple Service Source Manual for Quad G5. (Let me know if someone needs that!) and just getting to the cooling and the power supply seems a bit tricky. So I read about this Apple power supply exchange (http://www.apple.com/support/powermac/po...) and am trying for that first. So it seems from the LED light that the CPUs are overheated and that could be related to the power supply going bad. I will post results of my shot at Apple.

  • UPDATE - THINK I MAY GIVE UP **

I took the machine to an Apple service center and they confirmed it was the processors gone bad. Of course this has to do with the cooling failed. Still I was not able to get a warranty repair even if I showed them the extended powersupply article and the article about the cooland leak. They said the machine was too old. They did offer me to fix the machine for about $1300. Since this is 2 machines with same error and since I have 16GB of RAM invested in each one just before this all happened, I might just have to accept the offer. Any comments?


Antwoord

this sounds like a possible failed logic board or processor module. Since the 2.5 Quad is water cooled, first check the felt pad under the processor heat sinks - is it damp or stained? If so, stop trying to use the machine immediately - the LCS has failed!

Next, make sure you have a known good matched pair of RAM modules (these machine are VERY picky about matched RAM - try to use not only the same size, but the same manufacturer and code when possible) installed in the inner most slot of each bank - follow the diagram on the inside of the cover to ensure the RAM is installed in the proper banks.

Next, if the issue persists when you boot the machine after checking all of this, remove the cover and air dam and check the LED bank on the forward edge of the logic board, near the RAM slots:

http://support.apple.com/kb/HT2652

Red lights here are BAD (except for the "cover open LED" My guess is you will have either the "Overtemp" or "Proc" LED lit.

There are sources for the parts, let us know what you find...