If this part fits it should be a good candidate:
https://www.ebay.com/itm/1PCS-JAPAN-ALPS-RK27-A-100K-4-GANGS-Dual-channel-Motorized-Potentiometer/11...
https://www.ebay.com/itm/1PCS-JAPAN-ALPS-RK27-A-100K-4-GANGS-Dual-channel-Motorized-Potentiometer/11...

