This panel was most likely made by LG. Most likely cause is a faulty Y-SUS board. If your serial number falls in the range of XXX7F3XXXXX then the part# is 6871QYH053B which is listed at Andrews Electronics for $184.30 with a $50 core charge. It is also possible that when this failure occured that one or both of the Y drive boards were also damaged. However, they only list the upper Y drive.