USP loses the sound randomly
 

Hello.
I play with some friends, and the acoustic guitar of one of them is having a problem since some months ago. Randomly, while he is playing, the guitar sound goes completely off, then he taps the strings or the soundboard and the sound comes back for some seconds or minutes. At the moment he does that tap, you can hear also some kind of "pum" from the speakers, like when you plug or unplug something from the console without turning off the volume.
We have checked the connections inside the guitar, and battery and output are working fine. Maybe the problem is in the undersaddle piezo pickup.
Could someone give me some help with this problem?
Thank you.

It is possible. The Fishman Matrix is more fragile than its coaxial competitors (or the cheaper Fishman Sonotone which is also coaxial). Since coaxial UST's can be installed from inside the guitar they are often soldered to the preamp and not user serviceable. A Matrix UST replacement is pretty easy.

I didn't mention the brand of the USP....but actually it's a Fender-Fishman. Looks like a Fishman Isys, so I guess it comes with a Sonicore piezo pickup. I think it's a coaxial flexible piezo.

It might still have a plug connecting it to the preamp. A solder splice would not be too hard if not. There are gray market Sonotone transducers on eBay for reasonable prices.

Finally we have checked the piezo, which effectively is a coaxial piezo.
While the guitar was plugged to the mixer and speakers, we touched, moved and tapped the piezo and the cable, and the sound was ok all the time, without interruptions. So, it seems like the piezo is not the problem.
We received an email from Fishman, and they say that maybe the problem is anywhere inside the preamp.....:cry: