My new 840av is a source of worry to me, (already).
It is unreliable at booting & at displaying a picture.
It started making a loud humming a few moments ago.
I saw inside & the power supply if nothing else needs a good clean, so I shall get on with that tommorow.
Quadra 840av, prettymuchmaxedout8xcd drive,3 monitors 15" & 14" & 14" os 8.1
Powerbook Duo 280c, 12 meg ram, 500 meg hard drive