If routine checks do not locate the trouble, repairers refer to blueprints and manufacturers' specifications that show connections and provide instruction on how to locate problems. When locating the cause of electronic failures, repairers use several kinds of tools including voltmeters, ohmmeters, signal generators, ammeters, and oscilloscopes. They run special diagnostic programs that help pinpoint certain malfunctions. To make repairs, they may replace defective components or wiring, or adjust and calibrate equipment. Although it may take several hours to locate a problem, fixing the equipment may take only a few minutes.
Preventive maintenance is another responsibility of electronics repairers.
Equipment is checked, cleaned, and repaired periodically to detect and prevent defects. Records are usually kept to show the date and condition of the equipment serviced, and to indicate when it is due to be reserviced. Repairers also have to maintain records of repairs, calibrations, and tests. Industries that operate around the clock will often rotate shifts, so repairers may work evenings, nights, days, weekends, or holidays. For example, repairers working for hospitals may have to work evenings and weekends so that someone is always available to make emergency repairs to malfunctioning respirators and other life-support equipment.