No Display After Screen Replacement

Hi,

I cracked my screen on my Xperia X and have just replaced the screen but when I power it on now, I get no display. I also tried hooking up the old broken screen and that also does not display anything anymore.

The phone still turns on as it vibrates as normal on the boot up when pressing the power button but I have no display at all.

The phone still charges OK too as far as I am aware as the LED lights up.

My computer also recognises a device is attached when plugged in as I get the USB noise through the speakers but nothing showing up in my computer although I think this may be as it hasn’t fully powered up as I need to input a pin code.

Any ideas what the problem is here?

I was thinking I may have damaged the motherboard but the phone appears to turn on OK and I can also turn it off using volume up and the power button which turns it off after vibrating 3 times.

The only thing different I have noticed is that the LED notification lights up red for about 5 seconds when initially plugged in and then reverts back to the usual charging colour.

Any ideas what may be the issue here as I am currently phone less without this :(

Many Thanks

Matt