I am trying to repair a syncrowave 300 which has very low weld output (will not melt stick electrode). I have tried this machine with various settings (hi/low, AC/DC, with panel or remote control) and always the same thing. However when using the start current I can get plenty of power out, so the main power components are probably ok. I am guessing it is something in the regulation circuit and already tried swapping PC1, PC2 & CR1 from a working machine. Also the hall effect is giving a proper voltage signal representing the output current.
I am out of ideas here, any suggestions?