Diagnostic and Repair Technician, Junior Grade was an enlisted rank in the Bajoran Militia, which primarily dealt with routine station maintenance and minor repairs when necessary. This could involve repairing replicators or work in waste extraction.
In 2372, Rom quit his job as Assistant Manager of Policy and Clientele at Quark's to become a junior grade Diagnostic and Repair Technician on the night shift. He promised Quark that he would still repair his replicators. (DS9: "Bar Association")