As you can see in diagrams fans and also solenoid is driving by mains voltage.On a standard inverter welder the first part is the rectification of the ac to dc. there should be two 24v outputs one for the fan other for the gas valve. As for the 24vdc valve unplug and give a 24vdc or less 20vdc should suffice to hear the valve click. On one image that you post i saw some burn mark near the fast diodes (converting the high frequency ac to dc)
Hi Justin,I have a 19.2 reading from one side of the fuse to the other and no readings from the 3 x PTC, visually they look fine. Sorry for my naivety, but I'm checking the resistance from one side to the other with the multi meter, without any power on, is this correct? The DC Link relay I cannot get any resistance reading from either, using the two pins on the underside of the board.
Are you able to circle the "outmost right connector between yellow and black. I mean the 4pin shell with 3 wires on the other side".