On / off knob is EXTREMELY stiff, will click on and off but hard to determine what setting is selected

Seems to turn on and run, stimulator flashes at different rates depending on what's configured.  We're not sure what this scope is for and therefore unable to test it.  All other knobs besides the power move freely and seem to effect the display.

May have been a biological or biomedical oriented instrument?

SOLD FOR PARTS OR REPAIR ONLY! WILL NEED YO BE REPAIRED/CLEANED BY BUYER.