Finally it's open! The manual doesn't show all the parts, there are 2 screws in the red circle in the first picture, they are hidden under the rubber cover (about the small red circle in the second picture) you need to remove the screws before you can remove the blue frame, otherwise it will break like in the second picture! It's a nightmare!! Install 3 1.5V AA batteries and open the pressure tank! Oh yeah! The screen lights up and it still works!