I got two fairly dead Electrodragon relay module from a friend to try to repair it.
The first looked like maybe repairable:
The second is completely dead:
From this wanted to salvage the terminal blocks from the secondary side to repair the first module, and the ESP module to put onto one of my dev boards.
Removed the blocks and the ESP from the board.
Created a new dev module from it:
The build succeeded perfectly (I'm getting better in SMD soldering),
but when I connected it to the programmer even the programmer felt out from the USB bus.
So the surgery succeeded, but the patient died.
I also repaired the first module, but as is it mains connected I don't want to try out without some precautions. I don't have more time for this right now.