Our alternator on our mooney (1970 M20F with IO-360-A1A) went out about 3 weeks ago after we put about 100hrs on it since buying it. The terminal stud cracked toward the bottom of it and thus would jiggle and loose a connection. So we replaced it with an alternator from Kelly Aerospace (model ALY-8520R). Within 12 engine hours, the alternator broke in the same fashion. This time, we noticed that there is was Teflon (that’s my guess) insulator on the bottom of the terminal stud and it had a melted spot on it. So we tried a 2nd alternator from Kelly and within 6hrs it failed too in identical fashion.
Our A&P has spent hours talking to Moony ‘experts’ and everything they tell him to test, he has already tested. He’s also had another mechanic check his work and the failed pieces for ideas. One would think it’s an electrical system problem because of the melting spots. However, none of our electronics are failing….no fuses/breakers are blowing….nothing. Its crazy. The only symptom is that our ammeter would suddenly show a wavering needle and then slowly get worse to the point where our battery would be loosing a charge. We are stumped and not happy. Any ideas would be great! Or any leads on someone that might want to buy a used mooney that comes with 3 extra alternator cores. J
