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Monitor Warm Up Timer, Degauss Tester and Time Of Failure Recorder

IP.com Disclosure Number: IPCOM000122463D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 4 page(s) / 183K

Publishing Venue

IBM

Related People

Knox, AR: AUTHOR

Abstract

Test equipment and circuits are disclosed for use in a manufacturing plant to automatically monitor racks of CRT VDUs undergoing power-on tests such as degaussing, early-life failure and warm-up timing. Safety and efficiency in a manual assembly process are improved.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 37% of the total text.

Monitor Warm Up Timer, Degauss Tester and Time Of Failure Recorder

      Test equipment and circuits are disclosed for use in a
manufacturing plant to automatically monitor racks of CRT VDUs
undergoing power-on tests such as degaussing, early-life failure and
warm-up timing.  Safety and efficiency in a manual assembly process
are improved.

      On a manual assembly production line used for testing displays,
there is a time switch which shows when the prescribed warm-up period
has elapsed.  After this period, the display is moved to a test cell
where the color balance and geometry adjustments are performed.  This
cell offers a controlled magnetic environment which can simulate
various regions of the earth's magnetic field, depending where the
finished product is to be shipped.  The display is manually degaussed
using a hand-held coil prior to the adjustment process.

      The displays incorporate their own degauss circuit for a color
display.  During the warm-up period, the display may fail for some
reason.  The time to failure of the display is unknown and may be
appreciable if, for instance, displays are left in warm-up over a
weekend or during shift changeovers.  The early life performance of
the product, as shipped, can be accurately predicted over a large
sample if the shape of the "bathtub" curve is known from real data.
This information is not currently available, but this disclosure can
provide it.

      During warm-up the displays are face down on a tray. Thus,
neither the test raster nor the green LED is visible to show whether
or not the display is still working. Operators feel the rear cover
temperature periodically to check for this.  With this approach,
valuable space in the warm-up area is used by a "dead" display which
no one is aware of.  This disclosure in addition to testing the
degauss circuit and showing the time to failure of the display since
the warm-up was started, also gives immediate visual indication of
the failure of the display.

      The connection of the display to the mains is by a flying lead
with power permanently applied to it.  Under normal circumstances the
operator ensures that the power switch of the display is "OFF" prior
to inserting the plug. However, occasionally an error is made and if
the line cords have become worn through use, the application of the
mains is very "noisy" and may cause the display to shut down due to
excessive power line disturbance.  When this occurs, the box is
rejected by the test operators as being "dead on arrival", whereas,
in fact, the display may work perfectly well but has shut down to
protect itself.  This type of trip requires the power to be removed
from the display for a period of up to one minute before the trip
resets itself, during which period the display appears dead.

      The foregoing disadvantages are overcome by controlling the
application of power while the display is in the process of being
connected to the mains;...