It’s a bit of a pain to reach, but it can indeed be adjusted without disassembling everything... the orientation has to be just right for the mech to work correctly. Make sure you test all conditions (one, two, three balls) after adjusting, and note that if one of the switches isn’t registering after rotating the mech, the mech isn’t the only thing you can play with - you can adjust the switches too if needed. Good luck!