Good night. The problem presented by my blender is that it makes a lot of spark or generates a lot of sizzle in one of the coals, so that this sector is overheated, being able to damage the winding of the motor stator. I did a cleaning and took out the coals to check them and they are fine (I think so). Then I put the blender back together and the crackling continues. I appreciate if any of you can help me correct this fault.

Clean the collector carbon (and also the grooves between the collector sheets), luck and comment.