JP12 7 piezo volume is low

Hi everyone, this is my first post here and first I’d like to say that my JP12 7 is the most comfortable guitar that i have played, perfectly balanced. Recently however the piezo pickup has lost half of its volume. I have read an older thread here which covered the same issue but the solution was never presented however the thread starter had an admin person send a PM. I’d love for some information about what the issue might be and yes I have tried new batteries 🙂
Thank you in advance.
Pat