HiCustomer Thank you for submitting the question to Just answer.
The symptom you have on your tv sounds familiar but I could use a little more info to help solve the issue.
How long was the TV on before the problem started?
Does it occur intermittently or is it all the time now?
Does it occur on all channels?
HiCustomer Thanks for the additional details. Often tv manufactures will use a capacitor to coulple the audio signal to the audio amplifier in the tv. Due to the operating conditions in a tv (changes in temperature, etc.) the capacitors may leak and change value. When this occurs, it will render the symptoms you have reported.
Another situation, could be an open solder connection that cracked open.
These two scenarios can be easily repaired by someone with basic soldering skils.
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