Power button not working after flex cable replacement

Hello,

I have an Iphone 3gs that the power button didn't work so, I replaced the flex cable thinking that it was bad. Wow, what a feat! I got the phone re-assembled and it still does not work. All of the other buttons, volume up/down, mute switch, headphone jack, work as they should. This is the same behavior that it was doing before I replaced the flex cable. Is there something on the logic board that is causing the issue? I don't want to go through the painstaking task of putting in another cable. Is there something else that I can try?