Alternator - Any way to test rectifier / regulator

[BradT585]

I was riding yesterday and my IS died, battery dead. I was with the Iowa VRCC group so I had lots of help. We switched batteries with one of the other bikes and mine started and ran fine to get us the last 10 miles to town, 130 miles from home, of course. The freshly charged batteries was now dead, we are now sure we have a real problem, most likely the alternator?? I got a GW alternator from an other member here in town that he had for a spare. I will be installing it as a test unit but am still wanting to do all the testing that I can on the old one to verify the problem. I have read in the repair manual all the test to do with a multi-meter but see nothing about testing the regulator/rectifier. I have been comparing some readings between the take off the the GW I plan to put on. There are some inconsistencies but have no idea which is right or wrong or if they mean anything at all. I hate to replace parts without knowing if they are actually bad, and I never pass up the opportunity to turn a bad experience into a learning experience.  Any advise and suggestions are welcome. Thanks

[Thunderbolt]

it is in line between the alternator and the battery.  It is a flat fuse under two screws.  I had a loose screw on one end that was causing mine not to charge, which I caused myself, but took a few minutes to find.  It is just to the right of the row of fuses for the lights, ign. etc.  There is a spare inside the cover from the factory.
Regulator is in the alternator if I recall correctly.  Just put the meter across the battery terminals set to read DC Volts set to range above 15 volts or if autoranging, set to DCV.  Crank the bike and see if the voltage increases to close to 14 to 14.5 volts.  If it does not, the alternator or the fuse or wiring from the alternator is bad.
You can get a good idea just by cranking the bike in your garage with the light pointing to the wall.  If the light gets brighter when you rev the engine, the alternator is probably working, if not, well you need to replace it.