SAE-350 Will not create aux power or weld

[Caligner]

SAE-350 Will not create aux power or weld

Could be the shunt coils.
And I believe that machine is a Lincoln. Miller machines are big blue series.

[Jonny Rotten]

Hi All, I bought a Miller SAE-350 Deutz powered off the classified, bought it as the title says.last fall this unit was working perfectly, stored in a barn for the winter and now it wont generate on the aux or weld.brushes are free and stators are clean, notice alot of rust on the aux side. windings are clean nor burnt, I am told these units are bulletproof.Is there any other pointers I should be looking at?thanks for the help.