hi, thanks for using JA:
You may have accidentally changed the RF channel where the transmitter sends the sound signal to the headphones. There three main RF channels-each one is associated to different RFs bands. What we will, firstly, is to reconfigure the RF use in your heaphones. To do so, simply push the Auto Tunning button in one side of the headphones. Here is a picture where the button is visible:
Once pushed-the transmitter must to be turned on with an available audio input signal-, see if you have sound. If not, keep reading.
What we will do is configure the headphones with another RF. To do so, simply slide the switch located at the headphone's base:
Try another channel diferent from the one that you have now selected. Slide the switch in the transmitter, and then push the Auto Tunning button in the headphones. Test now if you have sound.
If you do not have sound, we will run a little test to be sure that the headphones are the problem. Simply, connect an MP3 player to audio in of the headphone's transmitter. Once done, start playing something in the MP3. Press the Auto tunning button again in your headphones and test if you can hear the Mp3 music. Let me know the results of the test to follow up with your issue in case it's necessary.
Regards! If that helped, don't forget to accept my answer!