iPod 6th Generation - Black screen

It's got a permanent black screen - still connects to iTunes but no response from any of the buttons on the iPod itself. I bought a new screen and fitted that and guess what...it still doesn't work. I've tried all the restarts and plugging it in etc. etc. Nothing seems to get the screen to turn back on. Any ideas? Is it time to trade it in? Is it worth getting it fixed?