What was found
AFTER TAKEOFF RECEIVED ACFT TIE 1 OFF ALERT. WITH NR 1 IDG DISCONNECTED, LOST LT BUSS AND MOST DISPLAYS ON CAPTS SIDE, EMERGENCY POWER CAME ON. ADG WAS DEPLOYED TO CHARGE BATTERY. FOUND BTR-1/INTFC FAULT CODE. PERFORMED TROUBLESHOOTING IAW FIM 24-20-37, FOUND BTR-1 FAIL INTERMITTENT, REPLACED BTR-1 (R2-4) IAW AMM 24-26-05-4. ACTIVATED IDG NR 1, RAN ALL ENGINES IAW JRH, ALL ENGINE PARAMETERS NORMAL. PERFORMED OPS TEST OF AC BUSS TIE RELAY IAW AMM 24-26-05-5, CARRIED OUT OPS TEST OF EPCU IAW AMM 24-08-01-5, ALL TEST SATIS TURN ON/OFF APU. POWER & ETERNAL POWER SEVERAL TIMES, FOUND AC TIE 1 WORK NORMAL. PERFORMED OPS TEST OF ESC IAW AMM 21-08-01-5, ALL TEST PASSED, AND PERFORMED BOTH FCC AUOTFLIGHT TEST PER AMM 22-00-00-5, ALL TEST PASSED, AC REMAINED CATIII. ACFT OK FOR SERVICE.