What was found
A/C GEN CAUTION ILLUMINATED FLICKERED ABOUT 10 TIMES BEFORE STAYING ON. REMOVED FROM SERVICE. INTERROGATED CDS AND NO FAULTS WERE LOGGED. INTERROGATED EPCU, FAULT 27 LOGGED. CHECKED NR 1 AC GEN CHIP DETECTOR, NO CHIPS NOTED. OPS TESTED AC GEN SYSTEM, OPS CHECK GOOD IAW AMM 24-21-00-710-81. AS PRECAUTION, MTX REQUEST R&R OF NR 1 AC GEN GCU. R&R NR 1 AC GEN GCU IAW Q400 AMM TASK 24-21-06-000-801/400-801.OPS CHECKS GOOD.NO FURTHER DEFECTS NOTED. INNTERROGATED EPCU AND FOUND NO FAULTS REMAIN. RETURNED TO SERVICE.