I only see 3 parts with heat sink paste on them, the large one at the top looks like the only one that was intentional.

I want to reverse engineer these things and figure out if something can be made to replace them as an affordable plug and play solution, just like the original design. These photos alone give me enough info on the circuit design, all I need to finish is part numbers or values from the components.
I want to reverse engineer these things and figure out if something can be made to replace them as an affordable plug and play solution, just like the original design. These photos alone give me enough info on the circuit design, all I need to finish is part numbers or values from the components.