Hi,

I'm sorry I don't speak spanish, so I will write in english. I have the same problem as you with this volume control potentiometer.
I will replace it myself as you did but I need some help.

What are the specs of the pot you used? 50k ohm? Linear? Log? Please, this information is most important to me.
Another great help would be to photo the circuit board in closeup detail from above and behind. So I could see what pins did you solder.

You did a great work with this one. Looks great.
Thank you.