Here’s a very specific tool that any/all Auto Electrical shops should have access too and the knowledge on how to use. Cody here is testing the outputs on an alternator, not only checking amperage output, but really putting the unit through its paces, low load, high load, low rpm, high rpm etc etc. Modern times often means rebuilding is not financially viable, however often replacement assemblies aren’t available, and a thorough bench test will give us a good guide prior to strip down. Very Very Cool old machine, a necessity for any Auto Electrical shop.