Sounds like a loose connection. Check the connections at the cap and on the back side of the terminals.
Look at the rectifier too to see if you burnt up a diode.

 

Is it still under the 3 yr. warranty. If so, take it to Lincoln......unless you find something as simple as a loose connection.

Dicking around inside the machine is Lincoln's job not yours if still under warranty!!

 

Found faulty conductor stranded power cable inside the mig gun repaired broken conductor and is running great. Thank you all for your suggestions.

Happy welding