The unit quit putting power out motor runs I am getting 4-5 volts out of the receptacles I took the cover off the end unplugged the connector from the windings to the control panel and got 1.5 - 2.5 volts out of each lead (4 total) I checked for continuity between the leads and have it between black and brown and blue and white. I switched the voltage regulator board and control boards out of my Generac 4000 (identical boards). The 4000 worked with the 7550 boards but still nothing on the 7550 with the 4000 boards. Brushes appear to be in good condition. I have not tried to excite the magnets yet. Any clue? It is a $1,100 generator with 120 hours on it only. It has been maintained and just quit putting power out while it was running suddenly. It was getting used approximately once a month for 10 - 15 hours until it stopped so I started using the Ingersoll Rand I have which is now doing the same thing (see other post) after I tried diagnosing it.