I have BDP1 and found playlists to be stored in /mnt/img/playlists
Connect from PC with WinSCP, user bryston, pwd bryston and you should be able to copy them
Then, if BDP3 have same structure, copy them back to the same location
Other option:
In Windows, Type in search "
Turn Windows features on or off"; a popup window with this name will appear
Scroll down until you find
SMB1/CIFS file sharing support; make sure it is checked
Then, when you open Windows Explorer / Network you should see
BRYSTON-BDP-1. Accessing it takes you to folder
user, where you have also folder
playlists where are your saved playlists

