3.
Basic measuring equipment. A technician uses basic measuring devices, such as oscilloscopes or
multimeters, to measure actual working values or signals in a radio or television set, as well as for
analyzing problems.
a. Turn on device. The first thing you would do to start the repair process is turn the device on
and watch, listen, and smell trouble ormalfunctions. After the initial diagnosis of which block or blocks
of the radio are malfunctioning, refer to the manufacturers manual, Technical Manual or Field Manual
for schematics of the equipment you are troubleshooting.
b. Read schematics. To assist you on the schematic diagram, both the operating voltage values
and typical waveforms should be printed. Also included on the schematic diagrams are the test points to
measure signals and exactly how the equipment is wired.
c. Use test equipment. As a technician you use test equipment to measure voltage, current,
resistance, or signal waveforms, then compare these values to the values indicated on the schematic
diagram. If some values do not agree with the manufacturer's manual, Field Manual or Technical
Manual (schematics), then you have probably located the trouble in your equipment. This is the point of
troubleshooting where your knowledge of the circuitry coupled with the information obtained by using
the test equipment plays a specific part in locating the malfunctions.
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