The power ON button has four timed functions:
1st) One shot = turn-ON
2nd) One shot (when on) = always goes the to HOME MENU
3rd) If kept pressed for 2 seconds = turn-OFF
4th) Kept pressed for about 10 seconds = HW reset, Forced turn-off, (interrupts the ongoing data saving in memory).
Press once the power ON button and wait until the start-up is completed, about 20 seconds (do not press it again during the start-up phase).
Press and hold the power ON button, the instrument will emit a first beep immediately and a second BEEP after about 2 seconds, then release immediately the power ON button (even if the display is still active and shows the batteries instructions).