Norcold Optical Display Board 631365 (fits the NX641, NXA641, NX841, NXA841 models) This is the optical board that fits all NX and NXA models, regardless of serial number. Fits these Norcold refrigerator models:NX641 / NXA641 series: NX641, NX641IM, NX641.3, NXA641, NXA641L, NXA641R, NXA641IM, NXA64... See More