You could try plugging in a voltage meter in the outlet with the Shopsmith to see if it shows a voltage drop. A plug in meter can be found at most RV supply stores. Do you use an extension cord to plug in your Shopsmith? If it is under size/rated for the power needs of the Shopsmith that could be the problem.
Mark V 520 S/N 09-11-01 completely upgraded to Mark 7, with all SPT's & more.
Model 10ER S/N R64000 first one I restored on bench w/ Shopsmith metal ends & retractable casters. Has Speed Changer, Model 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E S/N 1077 oldest one I have restored. On bench w/ Shopsmith metal ends & retractable casters.