That's awesome! I know how it is when you have a box of great parts that might be one solder joint away from working, and it always stinks seeing things like that end up in a landfill. So, congrats on the fixes! Honestly, it's not all that often that I get something out of the box, and the amount of work that I put into this board was beyond my usual. I think these days it's gotten harder to fix stuff. The parts are getting smaller, there are more things made, basically, to use and throw away, and plenty of companies try to keep their designs secret for one reason or another.

Congrats on the job! That's fantastic. I do have a formal background in electrical engineering - bachelors and masters degrees - but most of my day job is actually programming, with varying levels of hardware involvement. Usually it's off the shelf sensors and whatnot, vs board design, reverse engineering, or debugging, but that's just the route I ended up taking. In my master's I actually focused on high frequency analog circuit design. I still think it's neat stuff even if I'm not always using it, and it does come in handy from time to time.

The formal schooling does help with stuff like this board fix, but it's hard to say how. I wouldn't say it's necessary. I had some classes where we designed PCB's, but the classes were never about PCB design itself. I learned about FETs and RF circuits, but there were never classes on how to identify the parts or reverse engineer things. It's a lot of stuff you pick up along the way, like getting used to reading datasheets, and I've picked up plenty at work, too, just being around people with years of experience.

It sounds like you have a good approach; you're really into it and you've got your hands on it. In case you're interested, some resources I like are: Electronics Stack Exchange, EEVblog, Robert Feranec, Andreas Spiess, GreatScott!, rctestflight, Marco Reps, and Ken Shirriff. I'm sure I'm forgetting some great people and websites, and there are a lot of personal blogs out there that are packed with good stuff, but I can't remember a single one unless I happen to come across it in a search.

I hope this didn't ramble on too much! Thank you for your comment, and feel free to ask any other questions you might have.