What was found
FLIGHT CREW REPORTED AC ESSENTIAL BUSS CAUTION MESSAGE AND GENERATOR 1 FAULT IN FLIGHT. CREW RAN QRH AND ATTEMPTED TO START APU WHICH TOOK THREE ATTEMPTS. FLT DIVERTED, AND DECLARED EMERGENCY. LANDED SAFELY. LT & RT ENGINES HAD COMPRESSOR WASHES DURING OVERNIGHT MX. REPLACED RECIRCULATION FAN FILTERS, COMPLIED WITH HIGH POWER RUNS, OPS CHECKED OF AC SYSTEM, OPS CHECKED OF GALLEY HEATERS, AND OPS CHECKED THE RECIRCIRCULATION FANS. ALL OPS CHECKED GOOD, NO OTHER DEFECTS NOTED.