Does the Zune adapter plug into the usb port on the reader? If so, it might not have been charging your 505 properly, and could have actually been draining power.
I've read several posts here from people who have discovered that more often than not, ac to usb chargers don't work properly with the Sony readers.
To charge from ac you'll need a proper ac adapter (that plugs into the round port next to the usb port on your reader). The chargers for the Sony PSP work great for this--and are much cheaper than the AC adapter Sony sells for the reader.
Hope this helps--and welcome to the forum!!
dordale
