I received a nano small stone a few days ago and it has been working fine, but today it stopped working. The LED still turns on and the pedal does something, but does not modulate. When I flip the color switch or plug it in again it works for a few seconds then goes back to not working. I’m using the battery that came with it. Anyone know what I could do? I’ve got the warranty but if it’s an easy fix I’ll just do it myself. Thanks