MacBook Pro not booting

Hi

My macbook pro late 2013 15 inch not working after replacement of speakers which requires the removal of the logic board as they are under the board.

Here is the current behavior:

1) Pressing the power button spins the fan but no chime happens

2) No logo, no light on the apple logo on the back, no keyboard backlit when pressing the backlit buttons, pressing the volume buttons does nothing, brightness buttons do nothing as well

3) When doing NVRAM reset I hear the chime and I can repeat it.

4) When I release the NVRAM buttons and the computer starts still no light however pressing the volume buttons I can hear "voiceover on" or "voiceover off" so it looks like it's on the login screen and it activated the accessibility. Pressing the power button off to force shutdown and reoperating, it again stops working and I no longer get the sounds of voiceover and I have to do the NVRAM again to get the sounds.

5) SMC reset does nothing

6) Battery is so swollen that when I removed the back case, I can it attach it again even though it shows normal health and holds charge for 4 hours. Can the battery damage the logic board?

7) Do I need to do the NVRAM a certain number of times?

I was very careful when I was disassembling the board so I hope I haven't caused a damage to the board or any of the cables :(

8) What cables or connectors that I may have not connected properly that would cause this behavior?

Thanks in advance

Regards

Michael