Mac Pro First Generation Power Supply Unit (PSU)
I replaced RAM and added a modest 128gb SSD and so far everything is working great. Install was very simple, although I found that a couple of Torx screws on the old HDD were missing. This seemed to have no effect on anything, the drive seated properly in its bay. I suspect this may have been a second hard drive as the pull tab was also missing. This machine was purchased used to allow upgrade to Mojave, my 2011 MBA will be orphaned under the new system coming up.