657/658 smoke internal alarm. ~~~~~ 657/658 smoke internal alarm.  3658 D/L ER & found FC 721 (Smoke External). During inspection, no such fault was found on 657/658. Cleaned up #3658 #2E return grill smoke detection tube. Swapped #3658 fire control panel to #1658.  Chan SW 44439 Fire Control Panel (After Swapped) : #3658 - 557 #1658 - 389