You were just exceptionally lucky. That I had one and was looking for information myself. Also had no fear of opening the machine up.
It is up for sale so timing was critical. As next week it should be sold.
I do hope it helps and you get yours running.
I guess you guess correctly. No connection from PCB.
As far as light I did not look as my wires are broken off of the front panel light. Which may off been an old neon as I cannot see a lot of volts across terminals.
I was just looking for details online and found this thread.
I have one that I am just about to sell.
Euromig 200. It has been an excellent welder, though I only used as a domestic machine.
I bought one of the first to be imported into NZ. In fact when I bought it, they told me I had to wait...