Jet 16-32 Drum Sander

[murphy]

I have a Jet 16-32 Drum Sander and it has worked fine for years but lately it bogs down with slight pressure, I have always taken very light passes as I know it is not a thicknesser, but now all but the lightest pass and it stops mid way through the length, I have tried to see what is at fault but it is difficult to see, I have removed the drum and checked the large coupler which is tight on the motor shaft and the drum, both have a keyway which the grubscrew tightens down on so there is no slipage there, I wonder if the main motor is knackered, that is all I can think of, unless someone can suggest something else to try

 

[Fitzroy]

Are all the bearings ok, with pressure on the drum can you turn in by hand easily?