Oh dear. I was just scanning this page: http://www.nerd-out.com/forum/viewtopic.php?t=33708 which is asking for assistance with the exact same model of player as I have, and read the bottom post about the lens being knocked out of alignment by a bad disc. This is rather scary, as I have quite a few discs that have received circular scratches after being played or used in one of my writers. It's especially scary because my Panasonic RV31, which is horribly picky with writable media, seems to be acting exactly how many people describe (that is, after you start using +Rs with it, it seems to steadily get worse and worse at playing them, to the point where it will no longer recognize ones it used to play).

Who was the bloody frigging moron who designed the specs for DVD loaders and drives to allow the lens to move that close to the disc while attempting to focus? Many players, like my shitty (but once expensive!) Panasonic, will take a good twenty seconds occasionally to recognize a disc, and that is certainly enough time for the lens to do more than one focusing cycle.

Grrr...