Black Knight (1980) - Function menu issues / Settings jumping

For instance when I set Function 37 (Multi-ball difficulty) to “0” (Liberal) then exit the menu and start a game the track lighting for ball lock will not be running. This indicates the difficulty is set higher than “0”. So when I go back into the function menu 37 has jumped to “10”. So to offset this I will set it to “90” so upon jumping it will be a t “0” and the track lights work. Unfortunately this isn’t the only setting that jumps and offset settings only save until I go back into the function menu or they randomly decide to jump some more. Also upon starting a game the settings will jump for each player added (10,20,30,40) up to four players. Also concerning other settings that jump besides 37, some jump 1, 10, or several hundreds or thousands. Other than this function jumping issue everything with the game works as it should.

Any help in the right direction is greatly appreciated!

Big70