Without a model number and year I can't research (google, avforum, etc.) But at worst you may have to replace the main board. And NEVER update the firmware when it's working.
I have a problem with my hisense tv.I did software upgrade on my tv and i have no sound.It comes back for 5 min and gies off again(everytime it does that my tv makes that weird connecting sound-like DSL conecting)I did restore to faculty settings(both tv and sound)but still nothing, customer service is no help since my warranty expired.

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