Generac NP-66 generator, no power

Had a problem before and found the circuit board was bad. Now have similar issues. Double checked all breakers, fuses and transfer switch. It will start and run but doesn't produce power. The LED doesn't illuminate. Have tried several times to excite the fields with no luck. This is mounted in a 01 NRV front frame rails.
Anyone know how much of a job it is to remove the genie to check the belt and brushes and just what is involved?