why does my veritas r8 keep making sounds bell box problem ? urgent helps ?

hi lately when ive been setting my alarm when i go to bed and when it seems to set both panels and main panel are bleeping it stops for a minute and then carrys on ive opened the panel and it sounds tamper nothing seems rong in the panel no loose wires speaker is ok the battery is new cos it was up for a change but it dosent do it when unset so then i tried it on full i stodd still in the house and it also did it on full set and what else has happend is now when i set my alarm for when i go out the external bell sounds for about 6 seconds when before it flashed ive check panel again checked bell box and there wired fine i was wondering if my strobe light code of gone ? and help please ?