iPad 2 turns off when taken off charger

I have an iPad 2 that is having a strange issue that I cannot figure out at all. If its not on the charger and you try to turn it on it seems like you get a very fast and dim flash from the back light sometimes. However when it is plugged up to the charger and you try to turn it on, it works like normal and shows the battery at 100%. But as soon as you unplug it from the charger cable it shuts off immediately. I thought that it may have been just a defective battery. I replaced the battery but still giving the same issue. After playing around with it the other day I put a little pressure on shielding above the battery connector and it would turn on for along as I held pressure there. I made sure that all the screws were properly secured and i know that the contacts are making contact because it gives a brief flicker of a back-light. What I think it may be is the solder is giving under the shielding. I just want other peoples opinion as to what may be causing this issue.