My Quadra 660AV would turn on, chime, but no video. Tested everything. Then I remembered older Macs may not work if PRAM BATTERY dead. Checked LowEndMac.com . New battery. Works like new.Floppy Drive note: since I hadn’t used it in a while the floppy had decided not to accept disks. After removing cover, I noticed the control lever wasn’t coming out all the way upon disk insertion. So, some silicon spray on the lever mechanics, and things started to work. While I had it removed I did some cleaning with Q-tips and isopropyl alcohol. So much dust.
Macintosh Quadra 660AV