Among the artificial intelligence techniques useful in diagnosis the integrated diagnostic techniques are often presented as the most efficient to resolve practical problems. This approach may lack however some flexibility to be applied in many application domains, when the role played by users takes an important part of the diagnosis process. Hypertext systems offer now an interesting approach whenever users' interactions are important. However, to fulfil the requirements imposed by practical and professional diagnosis, hypertext systems must satisfy constraints, which generally are not considered for common applications of hypertext. They are, for example, the ability of offering different projections of the same document; effective automatic navigation tools, and a well formulated representation of involved knowledge concepts. This paper presents a framework to build hypertext system-based diagnosis. First, we propose a definition of hypertext systems, which is more appropriate to account for the structural properties, which exist in any document. These structures become perceptible by the means of projections. A projection is decomposed into two steps: an interpretation operation, which is the computation of the document, and an instantiation operation, which is the transformation of the digital document into a perceptible document. Second, we show that by separating nodes content from hypertext documents structures, it becomes possible to implement efficient tools for document reading and synthesis. Last we refer to a model ontology building method, which we use for building domain dependant diagnosis ontology to model hypertext-system based diagnosis. The project of building a hypertext-based system for aiding in the acoustic and vibration diagnosis of rotating machines is finally used to discuss a possible application of the system.