I had some intermittent starting issues with my commuter car, a '77 BMW 320i. I recently had an "expert tester" check out it's alternator @ Shucks. I watched somewhat impatiently while he fumbles through figuring out what leads to hook to what terminal, all the while muttering to himself. He muttered loud enough to be offered help, which he unwisely turned down. That's when I should have spoken up, but everyone deserves a chance, so I remained too quiet. After all, after a few moments, he did figure out that he was trying to hook up an alternator and not a starter all by himself. He gets it all hooked up and presses the TEST button. As sparks erupted and flew in most directions, he nearly crashed trying to get away from the evil machine. He then pronounced my starter turned alternator turned spark machine "broken". It created enough of a commotion that the manager, who I'm getting to know well, came over. After swapping some more leads around, he hooks it up and it whirrs to life. I don't know how after the afore mention lightning strike, but it tested good, although borderline enough for me to buy a new one. After that, I took the old alt to another AP store and had it tested w/ the same results. I was in Shucks the next day for another reason and called the counter dude "Sparky" and just got a sour look and a worse comment in return. Some just don't know how to take life in stride.