Chris,
I had a similar experience last week. Two months ago it looked like my alternator was going out. I had it checked at the diesel garage, and they thought it was my batteries (F350's take two batteries), so I went to Interstate Batteries to have them checked. They checked the batteries, and the tester showed that the alternator was bad.
I decided to replace the alternator myself. Installing the part is easy...loosening the tension on the serpentine belt is not, unless you have the right tool. Luckily my neighbor had a 1/2" ratchet that worked like a charm. Fast forward to last week, and the alternator died. I had to do it again.
This time, I had already purchased a 1/2" ratchet! It wasn't all bad, the alternator was replaced by O'Reilly Auto Parts under warranty, and I enjoyed a bowl of Butternut Burley while I worked. A friend came by to visit while I worked, and we went to lunch afterward.
The two-month-old alternator was fried at the point where the power source connected. It was black and crispy! I guess I just had a bad one. The good news is that my skill set improves with every repair I make on my truck!