I recently re-capped my Radeon 9000 Pro with all tantalum or polymer caps as it had some that were starting to look a bit sad around the base. It worked fine for about an hour and then I got a pink screen full of lines that quickly went to black and my video card started smoking. I pulled the power almost immediately, but no longer have an AGP Mac GPU to see if anything else in the system was damaged. Upon inspecting the board nothing looks or smells off except for a small black mark along the edge of the PCB itself. At this time, my best guess as to what happened is that the change in capacitor ESR did something to destabilize the converter, making it extremely inefficient and caused it to generate excessive heat that melted a trace inside the PCB itself. Probing around I found that one of the FETs and several of the caps on that power stage have a 30 Ohm resistance across them, which seems way too low for an unpowered converter to me; so the power stage is likely fried. I don't have much confidence in fixing it seeing as the damage appears to be in the inner layers of the PCB itself.
I'm not really posting this asking for help (if someone does have a long shot fix, I'll give it a go though). I mostly wanted to give a warning to others that have a Radeon 9000 Pro that needs new capacitors. Just picking caps with the stock capacitance and voltage specs don't seem to be enough to tackle this monster. I aimed for a ballpark ESR of 50-300 milliohm with my new caps as this has worked well for other boards I have re-capped. I know switch mode power supplies can be finicky beasts though and the 9000 Pro power stages seem to be quite picky indeed. Time for a new GPU!
I'm not really posting this asking for help (if someone does have a long shot fix, I'll give it a go though). I mostly wanted to give a warning to others that have a Radeon 9000 Pro that needs new capacitors. Just picking caps with the stock capacitance and voltage specs don't seem to be enough to tackle this monster. I aimed for a ballpark ESR of 50-300 milliohm with my new caps as this has worked well for other boards I have re-capped. I know switch mode power supplies can be finicky beasts though and the 9000 Pro power stages seem to be quite picky indeed. Time for a new GPU!
