Sega Genesis Controller port issues (or so it seems)

[Genesaturn]

So just recently my Genesis has decided to randomly cut off connection from my controllers. I was playing Shining Force the other day and suddenly I could only walk left...then it stopped..pulled the controller out and put it back in and worked for about 30 minutes then did it again. Tried different controllers and did the same thing. Now it doesn't work much at all. I did a google search and found a bunch of stuff, so I wanted some professional opinions from someone who knows the issue and what causes it. One website mentioned having to re-heat the contacts or even having to add more. Before even trying anything like that I would like to see what else can be done if anything. Thanks guys :)

[raylydiard]

cold solder joints if you have a soldering iron use a desolder pump and use new solder make sure you use 60/40 0.7mm lead solder.
as old segas use that solder.