Picked up a used MSI Ventus 1660 super with no video output for $50 to dip my toes into GPU repair. After some lurking around here, google searches, and youtube videos, I've gotten around to checking resistances, and checking for the base and minor rails. On first inspection, I didn't any shorts on any rails, so I powered up the card, and found the 5v, 12v, 5v, 1.8v, and Vcore(I hadnt found the 3.3v location at the time). Later, after finding the 3.3v, I got a pcie extension and powered up again. This time I found the 12v. 5v, 3.3v, 1.8v, Vcore, and Vmem. Later, when I wanted to doublecheck my voltages, all the rails weregone, exceptthe 12v. At no point during the 3 times I powered on the catd was there any video, but the fans always run at full speed when they are installed and the card is powered on. Any tips? Could something be intermittently failing? Also, I'm not sure where of if the pex rail is, so I don't know if it's working. I also don't have a boardview or schematic for the card.