Clindell,  Slot 3 on the R510 is the bottom PCIe slot on the expansion riser. (seen below) [IMAGE] What I would suggest is to remove and reseat the expansion cards, the riser cards, and then any cables running to either. Then try powering the server back up. If the error persists, I would suggest removing anything in slot 3 and then power to see if it clears.  If so the card is likely the issue.  You may want to consider updating the BIOS and iDrac at your earliest convenience as well. Let me know what you see.
R510 Description: A bus fatal error was detected on a component at slot 3, what is slot 3? The server is a 4 bay non hot swap with 3 drives in RAID5 on a PERC S300, the 4th channel has a 1TB SSD on it. I've updated the drives from 500GB to 1TB's and installed Server 2012 R2 SP2. I have had 2 of these errors in the last 2 days and need to know what to address. I'm thinking slot 3 is the PCI express bus, maybe PCI3 ASM1062 Serial ATA Controller can anyone confirm and suggest what to do?
R510 A bus fatal error slot 3