What was found
FLT#355, JFK-PLS. (AIRCRAFT PERFORMED AN AIR TURN BACK) ' AFTER GEN 1 FAIL. STARTED APU APU GEN FAILED AS WELL. RESET ATTEMPT FAILED. STARTED ON GROUND AN IS WORKING, BUT IS GOING IN AND OUT; REF LP 4183046, ITEM 1 (REF TSM 24-22-00-810-829A. REMOVED AND REPLACED GAPCU AS PRECAUTIONARY T/SHOOTING IAW 24-41-00.). APU GAPCU REMOVED AND REPLACED. OPS CHECK PERFORMED IAW AMM 24-23-51. OPS CHECK NORMAL. NO POWER DROP OUTS OR FLUCTUATIONS NOTED. A/C ACCEPTED EXT PWR WITH ALL INDICATIONS NORMAL WITH APU RUNNING AND WHEN SHUTDOWN.'