Dismantling a Capri 141 fot controller?

My wife has an old Capri 141 sewing machine which works fine but yesterday the foot controller started smoking. I learnt from an earlier post that it my be the suppressor but I assume that means disassembling the foot controller to get at it. As the foot controller has only one screw and removing this does not allow the foot controller to come apart I cannot figure out how to get inside. Does anyone know the answer to this puzzle please? The information on the foot controller is "Merritt Sewing Motor Controller, Part No 1.8158-001"