18. (Continued).
List the types of checks used in electronic troubleshooting according to
their usefulness.
(Check your answer at the bottom of
Page 117.)
19. The two most general types of checks are front panel checks and
operational adjustments. They can also be the most useful in getting
started on the right track when troubleshooting. Front panel checking
includes noting every aspect of the system's behavior. Turn it on; warm it
up; notice any normal or abnormal indications or outputs. Next use each
operational adjustment (volume control, channel selector, indicator control,
fine adjustment, intensity and contrast control, etc.) and see what effect
it may have on the malfunction. By then, the initial brackets can be
established on the block diagram (mentally or physically). Waveform checks
are the next most useful checks. Waveform checks provide a picture of the
normal and abnormal functions in the system. They help narrow down the
bracketed area to a stage or subcomponent. Voltage checks then provide more
precise information in the suspected area. Resistance checks give detailed
information about specific components. Last of all, when a part is
replaced, the troubleshooter performs an operational check and learns
whether he was right or wrong in his analysis of the malfunction.
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