Re: fixing a buzz...
Positions 1, 3 and 5 are for the neck, middle and bridge pickups respectively. Each position turns on only one pickup, not like positions 2 and 4 which turns on two pickups that will cancel out the 60 cycle hum. There is definitely some 60 cycle hum problem. If the wiring has a loose or open ground wire, the buzzing will be worse. However, your power line may also be connected to some devices that is running an AC motor or fluorescent light, which will also cause the 60 cycle hum. I would suggest plugging your amp to a known clean power source and see if you still have the buzzing. You may even want to play it on another amp and check it out.