What was found
PDIS 689 24-20 1465 20MAY20 GENERATOR #2 FAULT @ CLIMB FROM FL 300 TO FL 330. TRIED RESET GENERATOR #2 WOULD NOT RESET .ATTEMPTED START OF APU @ FL 330 WOULD NOT START.DESCENDED TO FL250 TO ATTEMPT SECOND START OF APU . APU WOULD NOT START. DECLARED EMERGENCY AND RETURNED TO MEMPHIS THE NEAREST SUITABLE AIRPORT REMOVED AND REPLACED #2 GCU REF. A300-600 AMM 24-22-12-04. OPS CHECK GOOD. PERFORMED 2 ENGINE RUNS WITH #2 GEN AS ONLY POWER SOURCE. NO DEFECTS NOTED VOLTS AND FREQS WERE STEADY.