1974 (I think... dont have serial no close at hand) Big 40. I was welding today, all was working as should be, then without warning, the weld current stopped. I checked the obvious... ground (tried arcing to ground clamp), cable connections, etc. I checked AC voltage with a VOM, has 124 volts at weld speed. Connected it between the welding leads (still at weld speed) it shows 0.8 volts. I didnt think to check voltage at the terminals where the cables connect, just to verify that all cable connections are good.

I have the manual and wiring diagrams, but my limited knowledge of the workings of a welder make it difficult for me to know where to even begin.

Any help will be appreciated.