I recent got a D-777 off a friend who 'upgraded' to a ej1000, unfortunetly he lost the external battery case for it. is the only to get one is to ask sony? and will there be any problems as this unit was bought in Hong kong?
Congratulations on you D-777!! Why do you need the external case? Is the Ni-Mh is not working any longer? Anyway, you should be able to get it through Sony. The part number is Batery Case EBP-20. Good luck on finding this! Your D-777 should totally destroy your friend's D-EJ1000 Headphone out! Click here for website. The price is around 14 dollars, so it not so bad!
Type "D-777" in "List Parts and acce...." and you will get the result.