Edwards S2M 540-01-b Turbomolecular Pump Controller Capacitor PCB Turbo Working. This Edwards S2M 540-01-b Turbomolecular Pump Controller is used working surplus. Only items pictured are included: If a part is not pictured, or mentioned above, then it is not included in the sale. Pictured test equipment is not included or available for sale. For items with multiple quantities: The pictured item is not necessarily the one that will be sent. Serial numbers or country of manufacture may vary.