The biggest problem that I have found with the older PCI PMAC cards is that the card can crack along the buss tab. This kind of thing is not repairable. This is caused by the end of the card not being properly supported, and the saw head is banging up and down because the air pressure is set too high. Verify that your air pressure is not set so high that it causes the carriage to "bang" as it moves. It can also be suggestable to support the loose end of the card with a zip tie to minimize movement.