How to repair the extruder port where the extruder stepper driver is placed. have anyone ever tried repairing it in the motherboard??

The stepper driver is directly connected to the microprocessor IO pins. (+ some connectors and soldering)

If its dead... you need to replace the Microprocessor.. this is not advisable, unless your good at SMD rework.

There are a two components related the to stepper driver that could make it seem dead... ie two resistors. Not very likley its them.

What's wrong with it? Do you have a picture?

Repairing RAMPS and similar electronics tends to be either a reasonably-simple solder job, or impossible.