plunkinberry,
The cab should be grounded...if it weren't then lots of other things wouldn't work. I'm a tad anal, so if the grounding of the field wire at the regulator end didn't make the generator hop to it, I would leave this wire loose and not touching anything, and do the same procedure at the generator using a jumper wire from F terminal to engine ground. This little drill removes any question that the F wire might be broken somewhere in its path to the regulator.
If these tests prove negative, it is telling you the generator cannot produce voltage. It will need to be operated on, or replaced.
If the full field test on the generator proves that it will function properly, then the voltage regulator comes into the spotlight. If it can't tell the generator to charge, it's defective.
The idea here is to prove the device you have the ability to test...the generator! Testing a voltage regulator is pretty tough for a amateur.
Stuart
