As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TECHNICIAN WAS CYCLING CIRCUIT BREAKERS DURING ANNUAL INSPECTION. TWO CIRCUIT BREAKERS WOULD NOT OPEN. A 1-AMP AND 3-AMP BREAKER POWERING AVIONICS AUDIO SYSTEM WERE REPLACED. AS A PRECAUTION TO PREVENT FIRE HAZARD FROM NOT TRIPPING, 1-AMP BREAKER DID DISENGAGE WITH MUCH FORCE AND A PAIR OF PLIERS. ELECTRICALLY, BREAKERS HAD NOT FAILED. MECHANICAL FAILURE POSSIBLY DUE TO AGE. SUBMITTER SUGGESTED CYCLING BREAKERS PERIODICALLY.