Partial part number (3512D) can be found stamped on the board
UE55MU6500UXRU
Both the ends of the CAT cable should be termed as EIA-568B & the cable should be straight & not crossed
please confirm that 58GE01M3393LNA66-A1 is printed on a sticker on the back of your original main board
UN48JU7500FXZA TS01
515C90102M05 Onn Main Board, MT90102-ZC01-01, 65R45AX, 50R4A5X, 43R4A5X, 75R4A5R, 55R4A5X, 75R4AX, 65R4AX, 65R4A5R 55" Partial part number (3512D) can180 Day Warranty! Part Number: 515C90102M05 Part Type: Main Board Location: 01C3 Additional Board Numbers: MT90102 ZC01 01 Notice: Recommended to order by part number whenever possible. Often times there are TV models that use more than one set of parts and or panels. Compatible TV Models: Onn 65R45AX, 50R4A5X, 43R4A5X, 75R4A5R, 55R4A5X, 75R4AX, 65R4AX, 65R4A5R