Retrocomputing has emerged as a distinct area of use in concurrent digital media culture. While research on retrocomputing has stressed the cultural importance of learning from practices such as retrogaming and preservation, this paper will emphasize the more material practices developed within retrocomputing communities, namely the electronic engineering of various hardware. Essentially, such retroengineering seeks to make older technologies operative in a present media ecology — something which puts a practical emphasis on media materiality and time-critical interoperability. Focusing on a number of hardware designs, both hobbyist and commercial, for the 1980s home computer Commodore 64, this chapter goes on to analyze their (joint and emergent) media specificities, raising the issue of what, from the perspective of intermediating retroengineered hardware, that is, in fact, being ‘re-presenced’. In terms of analysis, the diagrammatic media archaeography of Wolfgang Ernst is applied — a method and aesthetics focusing on the media materiality of the machine. The contribution of this chapter is materially grounded insights into the temporal transformation of digital culture and how chronologically disconnected functionalities tied to specific machinery can, when systematically joined, bridge, erase or transform the relation between new and old media.