DECstation 5000 Model 150

This upgrade guide covers the process of replacing the R3000 CPU module with an R4000 series CPU in a DECstation 5000 Model 150 workstation or server. The documentation details the necessary pre-upgrade checks, including verifying that the system is running ULTRIX and UWS version 4.3A or later, shutting down the system, and properly handling hardware components using antistatic precautions. It also includes instructions for the physical installation, replacing the external system medallion, and returning the original CPU module to Digital Equipment Corporation.