Part# A 26-0167, serial# CMM002170987, Mfg. date 9/87, with small board on top X axis Pwb 90-0051 3 591-0101 Rev. A, PJO 5/13/87.Large board on side of the machine, Pwb 70-0049 Rev. A, PJO 5/14/87. Zeiss parts and service Tel. 763-557-6026. Zeiss stated accuracy is.00041 volumetric and.00015 per axis.