Amazon.com: UpBright 12V AC Adapter Compatible with Roland SPD-11 SPD-20 SC-33 TD-5 Boss SPD11 SPD20 SC33 TD5 Total Percussion Pad Sampler 12VAC 500mA AC12V 0.5A 12.0V 12 VAC Class 2 Power Supply
How to replace backup battery on Roland TD-20 V-Drums Module - YouTube