Circuit drawing double side.

Looking at the board it appears that there is only 2 sides to the board.
Checking this out with a light under the board I can only see the 2 sides Top and bottom

I'm fairly sure that a board that old will only be two sided.

Mike.

Well that's good news, at least!

I must say you're not really going about the repair in the right way. Usually you don't reverse-engineer the entire board, you troubleshoot individual sections to find where the problem lies. That, of course, comes after a thorough visual inspection of all parts.

How about starting fresh: What is the welder doing when you try to turn it on? Is it completely dead? If so, chances are it's a problem with the power supply. That's usually the best place to start.

If you had a Program Like "Sprint Layout 6.0", you could upload those pictures into it and Draft It to create a PCB artwork.

The jumper wire indicates a repair or modification. If you are wanting a standby board, consider the time it'll take to rebuild the board from scratch.