These boards have been removed from mostly new MONITORS with broken screens and should work if properly installed. ACER X34 MONITOR CONTROL CONTROL 6871L-5170C / 6870C-0737A. Please verify that your board part number is the same as 6871L-5170C / 6870C-0737A. 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)