A jig can be used to site-test the accuracy of multi-meters that are used to measure resistances in a cathode ray tube production line without having to remove those multi-meters from the production line or ship them to a third party service provider for the testing. The jig is a box of electronics that includes a variety of known resistance loads that can be selected and then measured by a multi-meter to test and/or calibrate that meter. The jig includes a number of known resistance loads, a device for selecting a particular resistance load and electric contacts for connecting a multi-meter to the jig so that the meter can measure the selected and known resistance load. By comparing the measured and known resistance values, the accuracy of the multi-meter is tested.