This study examines the documents circulated among biomedical equipment repair technicians in order to build a conceptual model that accounts for multilayered temporality in technical healthcare professional communities. A metadata analysis informed by digital forensics and trace ethnography is employed to model the overlapping temporal, format-related, and annotation characteristics present in a corpus of repair manual files crowdsourced during collaborations between volunteer archivists and professional technicians. The corpus originates within iFixit.com's Medical Device Repair collection, a trove of more than 10,000 manuals contributed by working technicians in response to the strain placed on their colleagues and institutions due to the COVID-19 pandemic. The study focuses in particular on the Respiratory Analyzer subcategory of documents, which aid in the maintenance of equipment central to the care of COVID-19 patients experiencing respiratory symptoms. The 40 Respiratory Analyzer manuals in iFixit's collection are examined in terms of their original publication date, the apparent status of their original paper copies, the version of PDF used to encode them, and any additional metadata that is present. Based on these characteristics, the study advances a conceptual model accounting for circulation among multiple technicians, as well as alteration of documents during the course of their lifespans.