The problem is really due to the wires on the ammeter working loose.
Here's what the back of the gauge looks like:
Here's how to properly secure your wiring connections to the ammeter:
NOTE: These images are courtesy of Bill Taylor (SOBill)
I seem to recall a prior post that you should install a jumper-wire between the ammeter's posts if you're running a hi-amp alternator to keep the 35 year old gauge from getting too hot and becoming a source of a fire. This is the only post I could find on the subject, but I don't think it's the one I was thinking of:
http://pantera.infopop.cc/eve/forums/a/tpc/f/6450045562...280067562#6280067562
Maybe someone else can find it and add it to this thread.
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