What was found
RIGHT PACK TEMP EICAS AFTER TAKEOFF, LEFT PACK DEFERRED. RETURN TO ICN. FOLLOWED FIM TASK 21-51 FAULT TREE 844 PERFORMED T/S, FOUND RT STANDBY CONTROLLER FAULT. REMOVED AND REPLACED RT STANDBY CONTROLLER AND CHECKED OK, NO FAULT FOUND PER AMM 21-51-14/401. PERFORMED BITE TEST OF RT PACK TEMP CONTROLLER, FOUND PACK TEMP CONTROLLER FAULT, RAM INLET ACT FAULT, LT CHECKED OK. REMOVED & REPLACED RT PACK TEMP CONTROLLER (SOS PART) AND RT PACK CHECKED OK, PER AMM 21-51-14/401. NO FAULT MSG FOUND PER AMM 21-53-03/401.