I have a miller 200LE aead welder, the first problem started with low AC power output 50 volts. Next was real low weld output, after doing some troubleshooting I put new brushes and cleaned slip rings (3). Still had same trouble,next I found two blown diodes on regulator circuit card. After repairing that my AC output was OK 120 volts, now the weld output is still real low same as when this problem started.