Alternator problem?

[Scott Machalk <smachalk@domain.elided>]

I'm driving and whenever I hit the brakes, the stereo cuts out. This
happened for a few days and then the headlights started getting dimmer. Now
the ammeter is straight up at best and is usually showing a discharge. At
least before I could rev it and get a positive charge indication.

Also, it still starts fine so the battery seems to be charging fine.

Since this truck is still new (to me) all parts are suspect. Where should I
look first?

I figure loose wires, then battery, then alternator but I'm not sure.

Any suggestions? 

I imagine that I need to take care of whatever it is right away.

Thanks in advance.

Scott Machalk
smachalk@domain.elided
1979 Scout II 345 727 driving blind.