if the Juxbox is playing music and you set your music to off, it can no longer be heard when you turn it back on if the box is still playing the same record.
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If your issue is the same as @unknown mentioned, it is a duplicate of MC-103511.

It's not Quite the same as that I made a video easier to show than explain.
you put the Box to 0% and then when you turn it back on. the music does not resume playing you have to eject the disc and replay it. it does it with every disc
That is what MC-103511 describes.

It is a duplicate of MC-103511 🙂
Do you mean that setting the Jukebox/Note Blocks slider to 0% and then back to a non-zero value stops the music?