Hi,

Here is a link to the Ifixit guide on how to replace the motherboard in a Gear S. It is handy as it shows how to dis-assemble the watch. The charge connector pcb is accessible by Step.6. in the procedure. (click on the picture of the back cover in Step 6. to enlarge for a better view of the charge connector pcb)

Samsung Gear S Battery/ Motherboard Replacement

Here is a link to a supplier of the part. It is not a recommendation to use them. It is shown to give an idea of the price and what it looks like.

https://rounded.com/samsung-galaxy-gear-...