Hi new member here, for some reason the keypad on above alarm has stopped working , ultra reliable until now !!!, power light on main box is lit red , sensors are detecting , door chime inop, backlights on keypad working but power light on same is not ,, before attempting a quick look I would need to know that if the alarm starts how do I stop it as can't access code as pad not working , seems first call looks like the box and change battery , but don't want to open anything that will trigger alarm unless I know how to shut it up !! Any help guys will be great ,