Why doesn't my power flex cable not working after replacement?

I repair ipads and iphones as a hobby. This is the first time i ran into this problem. I replaced the glass and ripped the flex ribbon cable on the iPad 2 which is the same as the iPad 3 flex ribbon. I replaced the flex ribbon cable and that never worked so I purchased another one and thinking that I damaged the first one I purchased but the second new one doesn't work as well. I am trying to figure out what else could be wrong. The power, mute, or volume buttons don't work at all!