Why has my Eight arc Fusion stopped functioning

I've had my Eight arc Fusion for a few years now and i haven't had a problem with it until recently. The light goes on and off...basically my arcade stick turns on and off. im not sure if its the usb cable..or maybe the logic board is burnt out or something. It will work if i turn it a certain way or pick it up...it will turn off again. if i lay it flat on the ground...it stays on. Im not sure which is the problem