I have a strange problem with my Hictop Prusa i3 printer. Recently almost all my prints fail midway (even small prints that were successful in the past). At some random location and time, the x and y axis start moving in one direction either following a straight line or while making small semi-circles (while the extruder keeps running), until colliding with the frame a couple of seconds after. At that point the printer just keeps trying to go in the same direction while hitting the frame repetitively and the display appears frozen (print cannot be stopped from the display). To stop the print I am forced to completely switch the printer off.
I have already checked that all axis move smoothly, that the belts are tight enough (but not too tight), and that the bearings are greased. The printer was working perfectly for a couple of years until it never worked properly again.
I also tried a running a print in which the extruder and nozzle heater are not used (moving only the x, y and z stepping motors). This seems to make the prints run longer until the same problem happens again.
I would appreciate any support you could give me to solve this issue. I suspect it is an electrical problem perhaps triggered after overheating of a circuit component.