As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ORIGINATING FLOW FOUND OVERHEAD EMERGENCY LIGHTS NOT ILLUMINATING. REMOVED FROM SERVICE. NTERROGATED CMC AND FOUND FAULT CODEE 33500002CTI. C/W E175 FIM 33-50-00-810-802-A. THROUGH STEP 7.L.(2). FAULT STILL PERSISTS. REPLACED EMERGENCY LIGHT POWER UNIT BATTERY, FWD L.H, REF. AMM 33-50-01-000/400-802-A. OPS TEST GOOD, NO FUTHER DEFECTS. RETURNED TO SERVICE.