I took the alternator to a rebuilder who bench tested it. He told me that it was worn out. ie. it needed bushings, brushes and new regulator. I asked him if he was surprised that it was worn out after only 38,000 miles (60,000 km) and he told me that it was typical of a 150 amp alternator keeping the coach and engine batteries charged. He rebuilt it for $175 (Canadian) and warranties it for two years. I was very pleased. If I had bought a rebuilt off the shelve it would have been closer to $700 here in Canada. I reinstalled it, and I'm good to go.