What an interesting post. I can't knock the guy who originally tried the repair, though...I've been learning on the fly on a series of locos I recently bought at auction with a bunch of extra PS1 boards. But my overall investment was very low, and I am not tinkering with anything near as expensive as that Big Boy. I suspect Alex would have a heart attack if he opened some of the stuff I did and took a look. I'd be right at the top of the electronics Hall of Shame.
But it's comforting to know that, if I ever did have reason to get a super expensive part fixed, folks like Alex are out there to deal with it.
BTW...what an incredible looking model. The blowing whistle with the separate smoker was so cool!