with my EC-500, when i flip the tone toggle switch all the way up I have no sound at all. I have my volume on the guitar maxed out, fresh battery in the pickup. Every other tone works except for that one. Any diagnosis'?
I had this same problem. My problem was the tone pot next to the volume pot had moved, in the back of the guitar. Pop the knob off, pop the back off, hold and twist them gently until you get sound.
check the wires for that pickup. It's happend a couple of times to me on an old guitar that the solderings let go and you need to resolder.