Dead Puck? What to do next?

I have a Puck which seems to have died.

• I can't connect to the device via Bluetooth.
  
• If I pull the battery and reconnect it doesn't seem to help.
  
• No lights flash etc when it's power cycled (ie reconnect the battery).
  
• Pressing the button while adding the battery doesn't seem to help either (ie no lights or Bluetooth connection).
  
• I've tried 2 new batteries, so I don't think it's that.
  
  

Is there anything else I can try to bring it back to life?