cracked solder sometimes is visible, sometimes is not.
Trouble spots are the yoke connector, power supply to logic board connector, and flyback. But if it were me, i would apply fresh solder to everything on the board. If that doesn't fix it, then you need recap.

Click to expand...

Is it safe to rule out the main logic board? There doesn't seem to be a thing wrong with it, it's just the analog board that it seems needs attention. I'd probably just tune up the entire board with fresh solder. A recap probably won't be too difficult on these analog boards? If they're not surface-mounted I can get those done, if they're surface mount then there's gonna be a problem.