The bottom panel is easy to remove by removing the four screws in the feet. It exposes the bottom part of the drivetrain. It is best to re-attach the feet after removing the panel, so that the machine stands stable during further disassembly.

Here it was possible to see that that the axle could still rotate a bit. It is very difficult to assess what part blocked the movement.

Early on a needle was found falling out of the machine with the tip broken off, so after any removal of a panel all visible parts ahve been inspected to find whethe this tip would be blocking the movement somewhere.