[Issue]Replaced LCD and battery

Hi All, I replaced my broken LCD Screen and battery on my ATT LG g2 phone. This is the 2nd time I did this. LG logo pops up (indicating new screen works) and goes dark with a red blinking light. When I hold the power for 10 secs screen turns blue and stays. No question of recovery or download mode as the phone won't respond without the charger connected. Any suggestions??