As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHX\MCI - FLT 592 - ONE HOUR OUT OF PHX, THE STANDBY HORIZON FLAGGED AND THE CIRCUIT BREAKER TRIPPED. DUE TO MEL RESTRICTIONS, AIRCRAFT RETURNED TO PHX AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE POWER SUPPLY FAILED. REPLACED POWER SUPPLY AND INDICATOR. AIRCRAFT RETURNED TO SERVICE. REF CONTROL NR 95ZZZX3455. (X)