I just finished assembling my MK3 kit. Following the instructions, I powered on the unit. The LED screen shows the different available language choices, with the default being English. When I press the button to select English, the LED screen displays "Original Prusa i3 Prusa Research" and I hear fans spin up. After about 6 seconds the fans go quiet and the LED screen once again shows the different language choices available. If anyone has any helpful hints as to what might be wrong, please respond. Thanks!