Thank you for your super fast respond Hero999.
I found another one more readable I hope but still on jpg and I transformed it to png.
Unfortunatelly where I am now I dont have my osciloscope with me and I tried to measure it with a multimeter hopeing that I would see something, but I guess I am wrong on that
I measured the DC voltage and it seems normal to me, around 300VDC after the capacitors of the brigde and 12 VDC supply after the regulator. I checked also all the power mosfets, diodes, resistors and capacitors and the relay and the only damage I found is the 10ohm resistor after the TR2 power transformer. The weird thing is that a while before I measured the voltage on the output of the welder and I see 15VDC. I searched a little on the web and I found that the electronic welders give on the output a low voltage less than 50 Volts so if this is true 15 VDC should be normal I guess. So I guess it must be a current control issue. I also read somewhere that the currect is controled throught the small ferrite current transformer TA, thats why my attention fell on the part from the TA till the output.