Truck won't start

[dwjack]

Got a problem with my truck. While driving around Thursday I noticed the amp meter drop to 0 three times for about 10 seconds before coming back up. When I got home I shut the truck off and when I went to start it, it was dead.

I have a powermaster one wire alternator that's only about 1 year old and I thought I might have a problem with it. I tried jumping the truck but nothing. I charged the battery fully and it tests good but still nothing. When you stick the key in, the dash lights come on and it buzzes weakly but won't start. To make sure it wasn't the battery I swapped it with a brand new one I had and It does the same thing. There's not enough power to turn the headlights on or roll up the windows which seems like a battery problem.

I tried jumping it strait to the starter and was able to get it to turn over for short bursts before it stopped but it wouldn't start.
Anybody have any ideas for me to try?