I have a cheap Johnson Acoustic/Electric 4 string Bass that I have always played acoustic with no problems. I decided to mess around with it plugged in the other day and found a weird problem. The E, A, and G strings all pick up fine but the Piezo pickup is not picking up the D string at all. I know pretty much nothing about Piezo pickups so this may be something really simple but I cant figure it out. Any Ideas? Thanks in advance for any help.