Did you ever figure this out? On that other site, I found some threads about servicing or replacing the motor. Apparently very hard to get into this thing. something about twisting the top panel counter clockwise to access to screws under it. I haven't been able to budge it. The whiny motor after 2 years is apparently a common issue with this unit. I bought it specifically because I'm alergic to noise :(
Sorry, I did not. As you say, it seems very hard to get into. I found someone that had made a custom 3D printed tool to open the top panel. I don't have a 3D printer so it became too big of a project.