Big daddy enterprises sells connectors, pins . Make sure you get the correct size. A lot of people don't use IDC connectors anymore and go with triferican instead. Said to be more reliable. Misspelled .. Don't have time to look up correct spelling . You'll see what Type. I mean once you start searching. You tube ,pinwicki or Pinside search will show you how to replace connectors. You'll also need a wire stripper and crimper.

Looking at your picture you may have to change both the harness connector that plugs in and the board connector that gets pushed on to. If board connector header pins needs done I would get some help so you don't ruin your board. You can also search how to desolder the header pins and reinstall if you want to do it by yourself. Previous owner prob wired it the way it is because they did not know how to replace header pins on board . Good luck and let us know how it goes.