What was found
A SCHEDULED FLIGHT, THE FLIGHT CREW HAD ENGINES OPERATING AND GOING THROUGH THEIR GROUND CHECKS WHEN THEY HAD THE NR 1 ENGINE FEATHERING DURING AUTO-FEATHER CHECK. INITIAL AUTO-FEATHER CHECK, THE FLIGHT CREW HAD BOTH SWITCHES, NR 1 AND NR 2 AUTO-FEATHER, IN THE UP POSITION WHEN THEY NOTICED THE NR 1 ENGINE FEATHERED. FLIGHT CREW SHUT ENGINE DOWN FOR MAINTENANCE TO TROUBLESHOOT THE AUTO-FEATHER SYSTEM. MAINTENANCE REPLACED THE NR 1 AND NR 2 SIGNAL CONDITIONER TORQUE/SPEED (TSCU) UNITS WITH NEW TSCU UNITS. FLIGHT CREW COMPLETED THE GROUND CHECKS OF THE AUTO-FEATHER SYSTEM AND DEPARTED FOR TRAINING/TEST FLIGHT WITH NO FURTHER ISSUES.