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Browse Prior Art Database

Combination Test Adapter

IP.com Disclosure Number: IPCOM000110548D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Friedl, E: AUTHOR

Abstract

This article describes a test adapter by which test point grids of 12 mil or less can be tested.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 78% of the total text.

Combination Test Adapter

       This article describes a test adapter by which test point
grids of 12 mil or less can be tested.

      Presently, circuit boards are usually tested by universal
testers having a 100-mil test pad grid.  As the test points on the
circuit boards generally do not coincide with this grid, the grid of
the tester and the test point of the circuit board have to be
electrically connected.  This is done by means of an oblique needle
test adapter, depending upon the respective product.

      However, contacting the SMDs (surface mount devices) on the
circuit board with test point grids of less than or 20 mil is
difficult for the following reasons:
      1.  The test probe diameter presently is 0.5 mm, so that with
grids of 16 mil and over the probes may be contacted.
      2.  Obliquely positioned test probes require a larger hole in
the guide plate, which leads to inaccuracies when the probes hit the
product and to widened hole edges by friction.

      The proposed combination consists of an oblique needle adapter
and a vertical contact adapter.  The entire adapter is designed such
that all non-critical elements (test spacings exceeding or equalling
20 mil) are tested as before, using a deflected test probe, whereas
the critical elements (test spacings of less than or equalling 16
mil) are tested by a combination of a deflection test probe and a
second test probe arranged perpendicularly thereto.  This design is
suit...