Touch not working after screen replacement.

We replaced the screen on an iPod touch 4th gen. After replacing it we had to short out the battery to get the display to work as shown in the guide. This got the display to work but not the touch. We have tried 3 screens so it is not the screen. We have also made sure that the Digitalizer cable is connected right under the board. Is there anything else to try to get touch working. or is this a board problem.