Yamaha - MODX6 , MODX6+- 13-note Rubber contact strip 10437600 Rotary knob

Rotary knob

and this will require repair in addition to the battery replacement

Be aware battery leakage will have damaged the circuit board itself

with two solder pins

Designed for rear panel 1/4 inch jacks

Yamaha - MODX6 , MODX6+- 13-note Rubber contact strip 10437600 Rotary knob13 Note Yamaha Rubber Contact Strip (ZS089100 V7477400) This 13 note rubber key contact strip features embedded carbon bubbles that, when pressed by a key, make contact with the circuit board to restore signal and ensure accurate key response. It is specifically engineered as a direct replacement for Yamaha part numbers ZS089100 and V7477400.