miller trailblazer 251 no weld output

[jeff akin]

Just bought 1997 trailblazer 251 with 14 hours machine is pristine kept covered previous owner only used one job then parked inside shop and covered machine starts and runs perfect produces 120 volt a/c fine but no welding output checked 3 brushes all clean and free checked fuse under cover and wiggled all wires anybody have any ideas Thanks