I took apart my Valveking 112 to do a little cosmetic work to it, but when I put it back together the input jack stopped working. I'm still able to play through the effects loop, though. Can anyone help me with this problem?

Whenever the amp is turned on it hums, and continues to hum plugged into input 1.

Gibson Les Paul Studio
Peavey Valveking 112
Marshall 4x12 cab