Pull off the drum and clean it out until it's bone dry. Then dust it with some powdered graphite, or maybe talc. clean the rubber washer, too, and make sure it still has its "fingers." My two banjos need at least 14V to work. Some suggest adding a single diode to affect the sine wave to make vibrator-type accessories work better. I haven't tried this, but I picked up a bunch of diodes today for another project, and may mess around with this.