I have just got my brand new cowon J3 today. However, I am pretty surprised at realizing that i can't play the player during charging either through USB with laptop or USB with power adapter.
I search around the internet and know that it is quite common for player not being able to play during charging through USB laptop because the computer needs to access the player and the USB only supplies around 500mh (not enough power for doing both at the same time)
However, I also got the same situation with using USB power adapter.
Does every owner get this issue? if not, what kind of power adapter or USB cable you are using in order to let you play and charge the player at the same time