These boards have been removed from mostly new TVS with broken screens and should work if properly installed. SONY KD55X720E TV LED MODULE STO550AP5 51LED R REV01, STO550AP5 51LED L REV01 / 056380270491. Please verify that your board part number is the same as STO550AP5 51LED R REV01, STO550AP5 51LED L REV01 / 056380270491. 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)