Rock Band Drum Kit Help

[ProperBritish]

My drumkit has always been a problem for me for about a month, the red drum (the one used a lot if you play right handed, which i do despite being left handed) is slowly conking out on me. it's impossible to do rolls, and generally even keep a steady beat with it. ive tried everything, putting pennies in it, disassembling and reassembling the sensor, but to no avail. when i disassemble the sensor i can just tap it really lightly with my drum stick and it works.

Although upon reassembly it just doesn't work well at all. I'm out of warranty, meaning i cant ask for a new kit.

What should i do?