As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MDIS 590 33-50 0749 02APR22 YYZ OPEN U DURING PRE FLIGHT, EMERGENCY LIGHTING SYSTEM TEST FAILS AND SHOWING MSG BAT 1 LO. REMOVED AND REPLACED POWER SUPPLY, EMERGENCY LIGHTING BATTERY REF. AMM 33-51-01-4. PERFORMED ADJUSTMENT/TEST REF. AMM 33-51-01-5. TEST PASSED WITH NO FAULTS NOTED. MEL CLEARED. A/C OK FOR SERVICE.