I just got a Quadra 840av recently, but the logic board appears to be defective.
The seller told me that neither the SCSI nor the floppy ports work, and that there are artifacts in the video, implying that the graphics chip is damaged somehow as well.
I can either live without floppy and get a SCSI and graphics card, or (b) replace the logic board with a known working unit. Obviously, I prefer (b), so if anyone has a known working logic board for this model, please let me know.
I'm looking to spend no more than maybe $50 shipped, but I can go up a little more (to like $75) if it's a really good deal.
I'm located in California, and my ZIP is 94549.