I too have a crocked n900,

Works ok with a charged battery apart from it does not respond when a usb cable or wall charger are plugged in so cant charge or backup data (apart from bluetooth).

If i turn the phone off and plug any microusb lead into it it goes through the nokia screen with back light off and dots loading loop process.
Once i turn it back on it boots fine but cant charge or use as mass storage.

Any ideas?