The project focuses on electronic repair in CNC machine. This is justified given that electronic causes determine a high percentage of automated CNC machine failures. An intelligent maintenance workstation is proposed as a vehicle for redressing the problem of uncertainty in the skill level of repair staff and as a means of enhancing the pace of repair under normal circumstances. The suitability of expert systems in electronic fault diagnosis is established through a review of the literature and a realistic role for an expert system in the definition of the workstation is determined. Circuit interrogation is carried out using a combination of instruments, probes and driving software written in 'C'. Procedural guidance available from the expert system and detailed circuit knowledge is reproducible in the workstation from pre stored CAD data base files. In the absence of a CNC machine to carry out the implementation, a partial implementation only was possible. However all of the elements were included and credibility given to the proposal.