What was found
REPLACED CONTACT ASSEMBLY PN M3081 IN MAGNETO MN 4373 WITH KELLY AEROSPACE PMA CONTACT ASSEMBLY PN A-13081 DURING MAGNETO 500-HOUR INSPECTION. WITHIN 2 HOURS AFTER RETURN TO SERVICE DURING THE PREFLIGHT RUN UP CHECKS, THE MAGNETO CHECK INDICATED A ROUGH RUNNING MAGNETO WHICH WAS REPORTED TO MAINTENANCE. UPON TROUBLESHOOTING BY MAINTENANCE, IT WAS DISCOVERED A DEFECT IN THE PN A-13081 CONTACT ASSEMBLY WHERE IT WAS FURTHER DISCOVERED THE POINT CONTACT THAT IS ATTACHED TO THE SPRING WAS SEPARATING FROM THE SPRING. THIS PREVENTED THE POINTS FROM OPENING AND THUS PREVENTING THE MAGNETO FROM OPERATING PROPERLY. IT APPEARS THIS CONTACT POINT IS RIVETED TO THE SPRING, AND THE RIVET WAS WORKING LOOSE THUS ALLOWING THE POINTS TO NEVER BREAK CONTACT.