The course select knob on my Heading indicator seems to have stopped working. I have resetting my heading usig my magnetic compass and after pushing a turning a few times it just stopped working all together. Two questions: Is it better to buy a new one and replace it or get this one fixed? 2. Can I R&R this gauge or does it have to be done an A&P? I assume it I buy one the exact same weight then I do not need a new W&B.