Teardown of a $250,000 1991 vintage IBM 9121 TCM Processor module from a System/390 ES9000 Enterprise Server mainframe computer,. Amazing state of the art 63 layer ceramic hybrid module construction with 2772 pins! And Dave demonstrates an amazing BGA desoldering technique that can only be done on these ceramic hybrid PCB’s. TCM PDF: https://eevblog.com/files/ibm-system390-air-cooled-alumina-thermal-conduction-module.pdf Forum: ...