Actually, Bernina removes the old capacitors from the 730, because they wear out and are no good after 50 years. Or re-wire a new electronic foot control onto the old cord. With the 830 carbon pile foot controls, they remove the capacitor, and replace it with a ceramic thermal switch, which is mounted onto the ceramic shell, and is much safer. On the electronic 830 Bernina foot controls, we do replace the capacitor when the foot control starts to sputter, after the potentiometer has been maxed out. It's a quick un-solder and re-solder job.