plunkinberry,
Welcome to the Stovebolt. I'm not sure I can add more than the service manual does to help solve this problem. The charging system can be broken down into two basic components and if one is tested and proves to be good, then the other is usually the problem.
If you run the rig, put the generator into full field charge and your ammeter pegs to 'C' then the generator is off the list of suspects. This is done by pulling the field wire at the voltage regulator and momentarily touching it to a good ground.
I think buying a voltage regulator off of E-bay is sort of a pig-in-a-poke kind of deal...it could be toast but look fine. Although it usually isn't necessary to do this if the generator proper hasn't been disturbed, polarizing the system wouldn't hurt anything. Momentarily touch a small jumper between GEN (ARM) and BATT tabs on the voltage regulator.
If the battery is more than 4 years old, it could be headed off into the sunset. Check the water, clean the posts and give it a full, long charge.
You can easily check the fan belt tension and peek into the commutator area of the generator to make sure your brushes aren't 'stubs' and that the commutator isn't crusty jet black. The brush holders must not be hung up...they need to be shoving the brushes on the commutator.
Look at the wires on the generator for breaks and loose connections. The regulator grounds the field to make the generator charge so the F wire must not be broken anywhere as it heads to the regulator.
Try some of these things and let us know if you solve this problem.
Stuart
