Shutting down automatically when idle

[Aravind]

I purchased Cowon S9 recently. Its been having a worrying problem since day one. It shuts down automatically if left idle for a minute or so..but stays on when being used. I tried searching for settings in the device that will help but in vain. Thinking that it was a firmware glitch, I upgraded to version 2.51(earlier 2.41). Even that didn't help. Now I'm clueless. Please provide your suggestions...