Laptop wont turn on only with cable after clean up intern

Hello you guys,

today i bought 2 laptops acers aspire E 17

since they where a little bit old and i want to at a ram memory and an ssd to make the pc go a little bit faster , my laptops wont turn on anymore.

first i opend 1 laptop to clean up inside. and after cleaning up and replace the logic board back in place, the laptop only starts up with an cable. i taught that i might damaged something first, like the battery.

now i opend the other laptop and place that battery in to th broken one to test, but it did not work.. i replaced the battery in the working one and now the both laptops have the same problems… what can this be???

is it like you are not able to take the battery out or what did i do wrong??