Hey guys. I posted awhile ago about buying a peavey century head and decided to pull the trigger for 100 bucks. Came with a scorpion equipped 1x15 cab so I was happy with the deal. Anyways, there is a two position power switch with on-off-on modes. Manual says to just pick the one that doesn't cause hum. I'm assuming one is a ground lift mode? The ground prong on the power cable has also been pulled off. I'm going to get a new plug installed but does anyone know which position the switch should be in for proper grounding without the lift? I didn't get any shocks when I tried it out at the sellers place but I'm getting some small zaps at home. I won't be using it until the tech checks it but I'd like to know which option is which on the power switch. Thanks!