Hi folks, may I ask for some advice please? I've recently bought a second hand Variax 600 to replace my original Variax which I eventually wore out. It was fine for the first couple of weeks but now it's not letting me select any of the models. It plays fine as a normal guitar but pressing the select knob has no effect at all and the light isn't coming on. I've recharged the battery just to make sure that this isn't the problem (it isn't) but I can't work out what is. Does anyone have any ideas? Thanks, David