A few days ago I had a zero load on the Amp meter on my 1976 Arrow III. It lasted less than a minute. I first thought it was a sticky amp meter needle. Then a few days after the alt definitely went off line and I had secondary indications. Both times I noticed it shortly after gear retraction. I did cycle the Alt switch and reduced the load but it did not come back. The AME found that the alt belt was loose and tightened it, but there was no slippage indication on either the belt or the pulley. Could the problem be from a loose belt? What else could cause those symptoms.