Skills I (kinda) learned for the first time with this restore
Atari power brick type B specs & rebuilds
Atari Owl Eye coin door wiring
Basics of PCB troubleshooting
Basics of TTL design
Built a test bench for PCBs, built test harnesses
B&W monitor models
Tube testing
Monitor repair, tube & yoke swap ('kinda' kinda)
What's left to do on Canyon Bomber? The big issue is the audio. Both TDA1004 amps are dead which seems a common issue with this chip, they overheat. They're no longer available but I have a few donor boards, status unknown. I want to rebuild this PCB 'as original' so I can learn the audio section but going forward I may have to resort to add-on amplifier boards

Or figure a way to swap in TDA-1004A chips which it seems can still be had. They seem to be slightly different though and I havent devoted brain power to determining what changes would need to be made to the board.
And, I'd love to repaint the control panel and side art but that's just OCD. Will have to wait. I have one more bronze age cab to get done this year.