Sorry ;-{
As soon as you said smell I had a feeling.
Not sure if desoldering the RAM chip offer anything here as depending on what you have may not work in the other system. I’ve got two boards which I use to steal parts from to fix other systems. You might be able to get some value for parts
If you decide to replace the logic board here’s a listing of the P/N’s:
* 1.4GHz i5 16GB/Intel 5000 - 661-01023
* 2.6GHz i5 16GB/Iris 5100 - 661-01024
* 2.8GHz i5 16GB/Iris 5100 - 661-01557
* 3.0GHz i7 16GB/Iris 5100 - 661-01026
They range in price from $270 to $410 USD for the i7 board.