while connecting my center channel speaker, I used wires instead of banana cables and somehow and positive and negative channels touched each other. It was working fine but when I turned up the volume, the receiver shut itself automatically. Now after connecting again, I observed that the center channel and rear channel inputs are not working. I swapped the speakers to the front inputs and they work so the problem is not with my speakers or wires now. How do I investigate the problem and if it was because of short circuit or high load, how do I fix that on my receiver. It's a Yamaha RX v-567.