Upon arrival I found smoke detector on unit 1 supply in alarmed state, flashing once every minute or 2. Removed detector from the duct and cleaned it. When removing clear faceplate I found air seal wasn’t tight against the panel, letting a little air bleed out. Also found sampling tube wasn’t facing correct direction. Blew out any debri that may have been inside smoke detector and then remounted it. Smoke detector error code cleared when I put the faceplate back on but alarm flashed again before system could start. Tapped on faceplate above optic housing and relay started clicking quickly, in alarm then normal, in alarm then normal, finally it stopped in an alarmed state. Need to replace smoke detector, alarm relay has failed and won’t allow voltage to pass for unit operation. Had to disconnect alarm again to keep ac running.