I've recently got myself a boba helmet with a servo fitted to the rangefinder. Sometimes when I first switch the servo on in the helmet the rangefinder goes a bit mad - flicking up and down quickly before settling and working normal, or sometimes not working at all. There's a faint electrical feedback noise from inside the helmet. When it's working normally there's no noise. Does anyone have any suggestions where I should start to investigate, is it bad batteries, the remote control switch or the servo itself?