This training manual, which was developed for employees of an automotive plant, is designed to teach trainees to operate a portable weld tester (Miyachi MM-315). In chapter 1, the weld tester's components are illustrated and described, and the procedure for charging its batteries is explained. Chapter 2 illustrates the weld tester's parts, specifies their functions, and explains the different pieces of information indicated on the tester's liquid crystal display. The following items are discussed in chapter 3: weld tester assembly, cable positioning, toroidal cable parts and functions, toroidal coil, toroidal connector, toroidal coil setup, and coil fastening. Chapter 4, which details the individuals steps in the weld tester's operation, describes the following procedures: use the 50 Hz/60 Hz switch to set the weld tester's frequency to that of the welder being tested; determine the weld tester's present setting; use the weld tester's range switch; determine the weld tester's present range setting; use the impulse switch to set the tester to the welder impulse being measured; determine the weld tester impulse number setting; use the first cycle switch to set the tester to the welder first cycle being measured; and determine the weld tester first cycle number setting. (MN)