Ended up swapping the CRT/PAV out of a donor iMac. I didn't end up swapping the parts individually, I just removed the parts connected to the donor iMac's internal frame, leaving just the speakers, CRT, PAV and frame still attached, then built it up to completion with all the parts from the Graphite. Not sure how to change just the CRT, but i'd imagine it would require disassembling the system to the point of exposing the PAV board, removal of the PAV board (which requires discharging) and then the CRT assembly should be affixed to the face plate with 4 screws. That's just a guess though.