Hi everyone,
I fixed one of the cards myself, and if you can handle a soldering iron, you can fix this yourself too.
I too have a MacPro, purchased new in early 2008. The card went bad after a year so I replaced the card with the Apple card—took me half a day to locate one and drive across Atlanta and back.
The replacement card only lasted a couple of months . . . imagine my surprise. I went back to using my trusty G5 and have tried over the months to see if others had the same or similar crazy video issue.
I ran across this article, which discusses the capacitor issue.
http://teechmehow.com/?p=3&cpage=1#comment-2
This was the first I heard of the bulging capacitors being the culprit. Had I known about this earlier this year, I could have saved myself a lot of time and trouble.
The two capacitors that were bulging at the top cost all of $1.17 to order online, but I found some on an old PC motherboard (my wife uses PCs). (I tried Radio Shack, but their stock of parts is very limited).
I removed two capacitors (there were four) from the motherboard and carefully removed the bad capacitors from the video card.
You will need to make sure you put the negative side of the capacitor in the right direction. There is a ( — ) symbol on the side of the capacitor and there is a ( + ) printed on the video board circuit board.
Carefully solder the "new" capacitor in place and you are done.
If you have never done any soldering before, go to MAKE magazine website or find a site that walks you through the principal s of how this is done.
The capacitors you will need are 1500 UF, 6.3V, 105C High Temp.
I found these at www.mcmelectronics.com . . . I ordered some "spares" and the shipping was more than the 6 capacitors I ordered.
I put the repaired card in my MacPro and its been working perfectly for a day now.
I noticed that the capacitors I removed from the 7300 card were the same diameter, but a few mm less tall than the replacement capacitors. This presents no problem.
I hope this helps others with the same issue.
FYI, this is the first major problem I have ever had with a Mac, and I've owned many, many, models since 1987, starting with a SE.