Well, I don't know the 505, but 3 possibilities come to mind ..........
Can you do a reset ? Always the best first port of call .
Secondly, does the 505 not have an auto turn-off after a certain time ?
Finally, presumably it will stop when the battery runs down - then perhaps a good solid charge, from the mains preferably, will do something constructive
Beyond these, I think a call to Sony support might be needed.
