IPhone 5s replace screen not working?

Hi, I have just replaced the screen with a new digitiser and screen etc, but it doesn't work. When I plug it in the sound of charging goes of every 5 seconds so something is working just the LCD,
I out the old screen back on and it came on, then when I put the old screen in again for the second time that also didn't come on,
Any ideas? Cheers

Replace it again