SIEB & MEYER K258935 Processor Board

The SIEB & MEYER K258935 is a dedicated spindle processor board used in Atlas Copco CSS91 spindle systems. Manufactured by SIEB & MEYER Elektronik in Germany, this processor board is associated with the CSS91 family and is identified by part number 43.11.03.3 and internal reference #322633. Also listed under the CSS 91 designation, the K258935 serves as the spindle controller module responsible for processing commands, coordinating spindle speed and torque signals, and interfacing with the surrounding CNC control hardware. This board is typically deployed as a replacement or repair component within Atlas Copco CSS91 spindle configurations, enabling continued operation of spindle drives in milling or turning equipment that relies on SIEB & MEYER control electronics. The part appears in catalogs and marketplace listings as a CSS-91 spindle processor board, indicating its role as the processing core for the spindle control loop. Typical applications include retrofitting older Atlas Copco CSS91 setups, servicing spindle-driven machines in manufacturing environments, and preserving compatibility with SIEB & MEYER CNC controls used in precision machining. With its German engineering lineage and designation for CSS91 spindle control, the K258935 is a specialized PCB that upholds the performance and interoperability required by the Atlas Copco spindle ecosystem.