Black screen after battery replace

I replaced the battery using the hardware and guide from iFixit. Everything went well and after I put the case back on it booted to the desktop and I could see the new battery was recognised and charging.

After this i shut down and took the laptop home and now at home when i boot the screen is totally black (no apple logo, nothing) but i can hear the boot chime and the keyboard is lighting up. I could even ping it and get a response.

I've tried resetting the NVRAM and safe mode etc... but still nothing on the screen. Any tips?