You said you're shopping the pin. Did you have to disconnect any connectors under the pf to remove parts that you forgot to reconnect?

Did you try wiggling the connector that attaches to it? Looks like cold solder joints

Well if you wiggled that specific connector with the pin on (carefully) and the lights didn't flicker on/off, then the solder joints are probably fine.

Try the board without the leds: Put incandescents back in a see if they light in those sockets.

Also try these two things:

1. bend the two little tabs on the socket up a bit so that it fits more snug on the board when screwed on. (this will improve connection from socket to board)

2. Those leds probably have little filiments on the outside of them. Carefully pull them out a bit. The goal here is to make a better contact with the socket. (this will improve connection from led to socket)

Keep diagnosis this. You'll figure it out. Just be careful when playing around underneath testing with the pin on. Remove any rings on your fingers or watches.

if you zoom in to the connector, the joints look cold. I'd reflow anyway like someone said.

Reflow means to just heat up your iron and melt the solder on there to make the connection better. Just make sure not to fuse any of the pins together!

Any updates?

Curious