As far as my experience goes, gouging done properly has had no effect on the inverters I have used. POWCON 300S and 300st Years AGO.
It is my opinion that 250 amps is 250 amps is 250 amps no matter what is on the end of the cable.
Of course any evidence to support otherwise would be appreciated.
Gerald Austin
http://www.weldinginspectionsvcs.com/
If you know how to check the components,(usually an ohm meter will suffice) and the components are marked with a part number and/or value,you might want to obtain a semiconductor catalog from Newark Electronics and make the repairs yourself.I do not know your skill level so,I can't say.Check the components one at a time,mark them individually with a red paint marker...1,2,3,ect.At the same time write down the information on the component on a note pad.Take an inventory of the bad components and then make a decision whether to repair or throw away.Remember this.It's broken....therefore you have nothing....which also means you have nothing to loose by trying.