Sega master System Controller Prots Acting Funny

Hay I am having trouble with my Sega Master System the system was working fine until a few months ago it as something to do with the controller Ports every time I plug in the Controller Manually the D-pad wont respond and yes I have tried the Genesis Controller too its the ports them self I am not sure if its just need cleaning or there something woring with the connection but its dose not work properly when I bend it to the right hand with the other controller attach it works fine but if I let go it just seems not to work at all can someone help me on this on what to do if i need to fix something or replace a part thanks

 

Maybe there is a cold solder joint. If you can solder, resolder all the pins on that port.