GS-750 Plus Power Recepticle. Do to years of use and poor power connections, the recepticle can become damaged. Your plotter may need this recepticle replaced if you show symptoms including, power will not stay on or inadmittantly turns itself on and off. I have seen plotters that would make a sizzling sound or even begin the smoke when you turn the plotter on. These are sure signs that this part needs to be replaced.