Diagnosis of Malfunctions in Complex Electronic Assemblies. Final Report. Page: 47 of 66
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Production Results. The verifier was converted to a production tool and is
now in use. The down time is somewhat higher than desirable because de-
velopment parts were not as heavy-duty as production designed tester
components normally are. The faultfinding capabilities are close to design
Development of Tester Concept Number 2
This concept deals with the development of a tester with the design oriented
toward troubleshooting rather than testing. The best application of this
tester occurs when the troubleshooting work load requires so much time of
the inspection tester that additional test equipment is required to ensure
that schedules will be met, and when. adequate troubleshooting features not
found on the inspection tester are badly needed because of circuitry pecu-
liarities or special diagnostic problems.
From data taken during earlier studies conducted on troubleshooting problems
in the factory, it was determined that a telemetry power supply assembly had
diagnostic and testing problems that would be compatible with evaluation of
The power supply package had three circuit boards stacked vertically. The
electrical circuit was a chopper-type power supply that chopped the output
of a 28-volt battery to a 10 kHz square wave, then transformed and rectified
the square wave to the desired B-supply voltages.
The power supply was selected as a vehicle for evaluations for the following
" The troubleshooting work load was so heavy that additional test equipment
* Several diagnostic problems were encountered in troubleshooting the
When marginal over-current conditions existed, no functional check could
be made on the unit, since input power must be applied at full amplitude and
with a fast ramp to simulate field conditions. The oscillator would some-
times operate at lower voltage conditions and lighter than normal loads
without drawing out-of-limit current when various types of defects occurred
in the oscillator. The troubleshooters used a 28-volt supply and a 9-volt
battery to start the unit when troubleshooting the oscillator under these
conditions. The disadvantage of this approach was that no fixture was used
to assure correct connections and to expedite hookup. No automatic-timing
circuits were available to alert the operator to run-time limits and no over-
voltage or over-current protection was being used.
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Losure, J. A. Diagnosis of Malfunctions in Complex Electronic Assemblies. Final Report., report, January 1, 1971; Kansas City, Missouri. (https://digital.library.unt.edu/ark:/67531/metadc1031893/m1/47/: accessed March 19, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.