Swapped digitizer/screen now iPhone 4 [GSM] will not charge

I swapped my digitizer before I sold my iPhone 4 on eBay. Unfortunately I never checked the charging since it had good battery life on it. Everything else seems to work, proximity sensor and it did make/receive calls. I have had this particular phone apart a few times for various part being replaced. I am familiar with the inside of it quite well. But now it will not charge.

Any ideas?

Thanks!