In this 5 photos steps, you can see how to arrive to the center of the problem.
To unmount only is necesary one screwdriver and care. You need to unmout the 2 electronic boards to
arrave to the memory stick card reader that has the problem.
You need to clean the contacts oxid of the cable that conects to the reader.
Put the cable to the reader as hard as posible to ensure that the problem not appears again.