Hi all: I have an sa 250 with Perkins diesel that is not producing any current at the slip rings on the exciter....It runs fine, starts fine, but no power at all at any of the receptacles or at the welding terminals..I lifted one of the brushes from the slip rings and checked across the slip rings for continuity and found that the rotor is not open... Anyone have any ideas where I should start looking for problems? Thanks, Mike