AVP machines are probably the easiest ones out there to manage.

As long as you have an ekey7 and diag key.
If the buttons are actually not connected, you'll get a button deck tilt displayed on the screen when you boot the machine.
If you don't see that, they still work perfectly fine when pressed, the OLED screens on the buttons are just burnt out. Common thing with machines that have been running 24/7 for who knows how long. You can replace them, but not cheap. And the button layouts are pretty common and the same for almost any game.
Bet multiplier is the top row of 5 buttons 1x-5x
Base bet is the bottom row of 5 buttons, lowest to highest. Side buttons are spin on the furthest out buttons, the next one in is Max bet.
Just depends if you think it's worth it to replace the buttons. It's fairly easy to do.