My tig welder has only high frequency only, what's wrong?

by Jay
(Longview WA usa)

I have had my Linde (L-tech)250 amp TIG welder for about 25 years and it is a wonderful machine. recently i tried to weld some mild steel and accidentally hit the tig/stick with my knee without realizing it. the amperage control was set to maximum and i use a foot control. when i started to weld (the welder started the weld at full power and then lost power. now i can only get high frequency. Since it was set on stick welding and the control was set at maximum power i assume i burned something out. I checked the welding power lead for continuity and it checks out ok any ideas what my problem is?
Jay

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I have used the same welder before and it was sweet.

It does sound like you may have fried a board or something.

I am not a welder repair guy and you will probably need to take it in to a local welder repair shop to get it fixed.

the not so happy news it that it might be expensive.

anyone else got any ideas?