It looks like someone has made a complete mess of replacing the power socket. Does the actual socket look new i.e. are the internal contacts shiny and silver?
What i would do would be to take that power socket out and get a new one. It looks like you're actually missing two solder pads there, although i can't be 100% sure from the photo. Whatever pads are actually remaining need to be cleaned up with some solder wick.
You need to get hold of some thin but fairly stiff wire. Something like a fairly thick component leg, or some solid core hookup wire. Stick the new socket through the board, and cut a piece of wire so that you can solder one end through the hole on the socket pin, and the other end to the next solder pad into the circuit. By that i mean the first place the socket pin would be connected to, if it was still connected.
Do the same for all three socket pins. That way, even if the sockets solder pad is missing, you have a fairly decent connection to the circuitboard
Hopefully that made some kind of sense.
I can't really see properly from your photo, but when you have that socket out it might be an idea to check with a picture of another SK5 to make sure theres nothing shorted that shouldn't be.