This device has a design flaw which - if you're not careful enough - might lead to ethertnet socket popping out of the board and taking solder pads along on a bad day. And on a good day you might end up with partially working socket because only a smaller part of the socket will lose contact with the board - power but no link, link but no power, etc.
The bad thing is that the PCB is a multi layered one and you can't really see where the traces go. The good thing however is everyone uses a more or less reference design for ethernet sockets with isolation transformers. And it's easy to figure out what goes where if you know where to look (so I did).
The board utilizes an isolation transfermer U15 (Yuan Dean Scientific 15FB-10BNL) which includes four differential line isolation in a single package (IN and OUT sockets). The IN socket goes to pins 19, 21 (tx) and 22, 24 (rx). OUT socket uses 16, 18 (tx) and 13, 15 (rx). PoE for the input socket goes to the lower bridge rectifier BR2 (Vishay DF01S).
The fix:
- Use good polymer glue to fix the socket to the PCB!
- Use jumper wire to join the socket, transformer and bridge together acording to the picture
- Presto! You have your socket working.
Should be something like this, if my memory and notes serve me right:
