Share your experience!
Cannot charge a 505. The screen has gone dark with an exclamation mark in the middle of it and at the bottom of the screen it says 'No Battery'.
Sounds rather like R.I.P. battery, I'm afraid.
There is - on utube I think - a video about replacing one on an older model like the 505.
Or, MobileRead forum certainly has threads about various D.I.Y. battery changes, etc...
( Worth joining anyway, if only for their free library, other sources & resources, Book Clubs etc.. & lots more)
But also worth contacting Sony support.