Ammeter fluctuating

I noticed on yesterday's flights my ammeter needle was dancing back and forth around the "zero" top position. Very small amplitudes on either side of the zero top center. Also the digital voltage indications on the Davtron 655 was jumping back and forth 13.8 and 13.7 V. I didn't think much of it as I was setting up for an approach. Didn't check the EDM800. I had the master switch replaced last annual and I still have to check the connectors in the back to be sure they're nice and tight.

I'm happy to report the ammeter fluctuation is no more! Condition cured! Battery is good and so is alternator and master connections. What I did was remove the left most panel piece that the ammeter is on along with clock and ignition switch. My goal was to check the connections to the ammeter, clean them and tighten them. There are two boots that cover and protect the connections behind the ammeter. One had slid off exposing the connector so I secured it. The other was in place. That seems