Black screen with solid blue light after teardo, tried button restarts

Hi I recently took on a Samsung Galaxy s6 after a teardown but it's been given to me with black screen and a solid blue light which doesn't turn off, I've tried charging on Wall for a day, the charging led went from Blue to red after about an hour or so and started charging but the screen was still black and then I tried to turn it on again and it flashed a green/grey colour on the right hand side of the screen bit kind of faded to the middle and was black on the left, happened very quickly and I only just noticed it and the phone pretty much just did the same thing again..

I'm leaning to heat damage on the actual lcd because it looks like they've had a good go at taking it apart but I'm unsure as I thought the phone would still turn on and do everything as normal just with out any picture, specially without a solid blue light which makes me think it's something else.

Any input would be great as I've never come across this before and I have tried all the button restarts and so on possible to sort this and definitely think something needs replacing.