I had the same problem. Buying a spare motherboard from OnePlus is said not possible by them.
I tried to unsolder the sim card socket with a hot air solder station. Way too risky as there is too much little components around. Overheating them may result random behaviors afterwards. Moreover, there is 13+ solrdering points not accessible.
The trick I used is to replace the damaged pins. Here the way to proceed - We are considering here you already took the motherboard out of the OnePlus One.
1/ Needed tools
- Office adhesive tape
- A Dremel with a diamond cutting disk
- Clock repair magnifier
- Soldering paste
- Hot air soldering station
- A spare sim card socket adapted to the OnePlus - got from Aliexpress
- Apply adhesive tape all around the socket to prevent small metalic particles to go everywhere and cause short circuits
- Use carefully the Dremel to open the sim socket - Image below. Pay attention to the ejection mechanism and let enough material on left and right edges.
- Get the required golden pins from the spare sockets by cutting them
- Remove adhesive tape
- Apply a very small amount of soldering paste below the golden pins
- Use the tweezers to place the spare golden pins on the original sim socket
- The hot air soldering station set at 250°C, low air speed, will melt the soldering paste
- Let everything cool down
- Test that new pins are soldered with the tweezers
- Adjust the heigth of the other golden pins with the new ones using the tweezers
- You're done - image below