Power Mac G5 - Video card / Fans problem

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Hey, having some trouble with a Power Mac G5, early 2005 model.

To start with, the G5 isn't based in my own office so some of the observations are based on second hand reports (mainly from people who are oblivious to what's going on with their machine) and some of my own observations from limited usage of the machine in question.

About two weeks ago, the machine stopped outputting to the monitor. I've checked the monitor, cables and DVI connector - all works perfectly - and a replacement monitor didn't help so the issue definitely lies with the machine.

At the same time, the top fan between the optical drive and hard drive bay started running at full speed and sounds like a jet taking off and has never been an issue previously. One of the front fans is also spiking in speeds - running to full speed for a few seconds, slowing down and then speeding back up again. I've never noticed it doing this before and no one else could remember it doing it either but it's possible that this isn't related to the other two at all. As I said, the people who use this machine are largely oblivious.

My assumption was that the video card (I think it's an ATI Radeon 9650 - judging by the board serial number) might be to blame so I tried running the machine without the card and the fan speed started running at normal speed so I thought my assumption was correct and started looking at a replacement card. However, after maybe 10 minutes, the fan goes back up to full speed and remains there so now I'm wondering whether the problem is beyond the video card and is either the mainboard as a whole or possibly a fault in the AGP socket. Just wondering if anyone has any suggestions? Should removing the card remedy the fan problem if the card is to blame or is it possible that the fan would run faster than normal without the card?

I'm largely a PC user so my normal approach would be try the card in another PC or test out a different card but unfortunately I don't have access to any other Mac hardware and because of it's age, I don't even have an old PC AGP card that I could flash and test out. I'm inclined to go and buy a new card and test it out but it's not my money to waste if it doesn't work and I know that Apple repairs here are relatively expensive - I know one authorised repair centre is looking for €200 for a new card alone.
 
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This is likely an issue with either the CPUs overheating, the power supply, the logic board itself but the Video card could still be in question. The reason the fans went to full without the video card is that OSX won't boot without the video card and it just sat there then went to the default fans spinning up mode. Try a replacement Video card and see what happens, but be ready to be disappointed.

You can reset the PRAM, check the RAM, make sure all the cards are seated correctly but in the end you best bet is to just replace the machine itself. When the G5s fail in this manner it's usually something large, like the logic board, and the cost to repair is not worth the value of the machine.
 

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