GE RFX/SFX Fluoroscopy Table | Block I table error

GE rfx/sfx table gives an error code of 1018 when the transverse movement button is pressed. On power up it gives an error of 0AC. 1018 in the manual says found low signal on U223. There is no U223 on the board. I was not able to locate the error 0AC in the manual. Any suggestions would help. Thanks.