Hi, Is it a fixed machine or a mobile unit?
Try checking the rotor cable for breaks or damage.
Do any relays operate when you push the handswitch?
Does the machine have a safety switch in the tube if so is its cable ok. What model of machine is it?

Kind Regards

Keith

We all have 20 20 hindsight. If anyone knows where you can buy a retrospectoscope please let me know.