I'm doing this from an iPad and can't seem to be able to attach an image. I'll try on the computer shortly. But to further the discussion, you may not see the break, it can be less than a millimetre to break a connection. Here's a way of checking it.
Plug in the offending trigger to the module, but don't mount it on a drum. Make sure the threasholds is quite low, say -36 or something. While holding it in one hand tap the piezo with your finger and with another finger press on the piezo so you're compressing the foam. If you hear the occasional triggering of the sound, it's a break in one of the connections.
Pic of best way to solder it (if thats what you choose to do) to follow.
Plug in the offending trigger to the module, but don't mount it on a drum. Make sure the threasholds is quite low, say -36 or something. While holding it in one hand tap the piezo with your finger and with another finger press on the piezo so you're compressing the foam. If you hear the occasional triggering of the sound, it's a break in one of the connections.
Pic of best way to solder it (if thats what you choose to do) to follow.