These boards have been removed from mostly new MONITORS with broken screens and should work if properly installed. LG 38UC99-W MONITOR MAINBOARD MAINBOARD EAX66940003(1.0). Please verify that your board part number is the same as EAX66940003(1.0). The part number is the first number left of the /, or the sole number listed. Most often written in title as (part number / board number)