Norcold Front Optical Board 638997 (fits the NX641, NXA641, NX841, and NXA841) This is the front control board for the following Norcold models, regardless of serial number:

Norcold Optical Display Board 640087 (fits the N10DC) This is the front optical display board for all N10DC models with a serial number above SE079WDW00190.

Norcold Optical Board 640089 (fits the N8DC and N10DC) This is the new optical control board for the N8DC, N8DCSS, N10DC and N10DCSS with a serial number above SE079WDW00190.

Norcold Optical Display Board 637081 (fits the 2118 models) This is the front Optical Control/ Display board board for all 2118 model refrigerators, regardless of serial number. 

Norcold Optical Display Board 628970 This board fits all 1200 model refrigerators with a serial number above 8981138. If you have a 1210 model, you need a different board. Below is a reference guide...