Connection to charger not recognized - won't charge

I recently replaced the screen assembly on my son's Ipod touch (16GB, no camera). The first time I did so, the screen had white lines, iFixit sent me a replacement and I swapped it out. No lines this time but now it doesn't charge. The batter symbol shows with a sliver of red showing. I've connected it to a cord that I know works (because it charges my iPhone) I've also tried connecting to my computer. My computer doesn't recognize it so iTunes doesn't start. I've tried to reset it, and I've taken it apart to check the connection to the logic board which is good. the cable isn't torn either. Any ideas?