Specs on the TV say it has a coax digital connector. You need a coax to optical converter.https
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/www.amazon.com/C2G-40018-Coaxial-Toslink-Converter/dp/B0002J2MV4
They only work in one direction so you have to get the right one.
Other option is to use the headphone output of the TV. Won't sound as good. Check the TV manual on using the digital audio output.