hi all from sunny lancs. Ive got a hopefully small problem with a borrowed welder.a cebora 812 which I loaned from my club to do some welding,It hadnt been used for about five years and nobody could remember what was wrong with it so I said I would try and get it going and use it for a while.So after cleaning inside switched it on got lights but no spark. Started with torch stripped it down and found a contact missing from wires in torch,it looked like a small fat question mark so set about making one fitted it to torch tried it and low and behold it worked patted myself on the back and got on with my project not welded for years so experimented with wire speed and power settings,This is a lovely welder to use and a nice light torch with plenty of power.Anyway lasted about two hours in total then the main contactor stopped working the wire feed and the gas valve seem to be still working but the contactor is intermittent at best,so i thought bad connection stripped contactor down of the four connectors on both sides only the center two are used and they were badly worn so used the two out side which were as good as new remade the 24v coil wires rebuilt and tried again worked again but then it gave like a double click on the contactor and stopped again now somtimes it works somtimes it dosnt checked trans getting 24v.checked pcb carnt see any damage parts,Sorry for the long winded explanation but can someone explain what the pcb does in relation to the contactor in laymans terms as I am an engine man really no idea on electronics,Or any ideas regarding the problems thanks hopefully mike,