Help with motor problem on Bernina 530-2?

I have an old Bernina 530-2 with knee operation (no foot pedal). One day it started to go on its own and I could smell burning so I pulled the plug out. Now it blows the plug fuse every time I replace it.

The burnt smell is coming from the cylinder on top of the motor - suppressor?? I asked a local repair man to have a look at it and he initially said the suppressor could be removed as it was not necessary nowadays, but then he told me that as there was a wire going into the motor he couldn't do that. Can anyone confirm that is the case?

There are four wires from the suppressor, two go to the contact points just above where the power lead goes, one goes to the square white bakelite (?) object on top of the motor and the other appears to be soldered to the top of the motor.

I would be really grateful if anyone can help me with this.