I've been working on a Big Guns I recently bought to bring it back to life. I purchased it from an arcade owner who had had it in the place for years, and while it was kept mostly functional, it definitely needed some TLC. Since bringing it home I've stripped and cleaned the top of the playfield, rebuilt the top two flippers, installed a new PinScore LED display, and corrected some incorrect fuses. I also installed all new flasher bulbs in all flashers. The game has been suffering from an adjustment error upon booting (Factory settings when the coin door is open), but there doesn't appear to be any corrosion on the board or battery holder. The game will also sometimes buzz upon startup, and once after putting the playfield back in and reconnecting everything, a few solenoids fired when I powered on the game, and then in the solenoid test all solenoids past 16 weren't doing anything (Not even a click from the solenoid relay). After power cycling this issue went away and I haven't encountered it again since (Although I haven't done much testing since).
I'm going to try a few things to see if I can fix the adjust failure before asking for help for that here, but I'm mentioning all that stuff here in case it is useful info for another issue I'm having, which is that most of the flashers on the game aren't functioning. Only the two flashers at the very top of the backbox (Both of which are solenoid 16) and the invincible flasher (Solenoid 15) work. All the others don't seem to be functioning. All other solenoids work though, it's just the flashers I'm having issues with. Where should I go from here?
Edit: See post #8 for info on the lamp matrix issue: https://pinside.com/pinball/forum/topic/most-flashers-not-working-on-big-guns#post-6057198