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Finding Short Circuits in Multilayer Printed Circuit Boards and Assemblies

IP.com Disclosure Number: IPCOM000077256D
Original Publication Date: 1972-Jul-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

DeGroat, PM: AUTHOR [+2]

Abstract

This device provides nondestructive means for determining the exact location of an electrically shorted path between two or more normally isolated circuits in a printed circuit net or between layers of circuitry in a multilayer laminate.

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Finding Short Circuits in Multilayer Printed Circuit Boards and Assemblies

This device provides nondestructive means for determining the exact location of an electrically shorted path between two or more normally isolated circuits in a printed circuit net or between layers of circuitry in a multilayer laminate.

A card and board clamp 1 is hinged on a square aluminum base 2. Also attached to this hinged clamp are two contact arm assemblies 3. The purpose of this arrangement is to be able to swing the shorted circuit board 4 so as to allow the operator to attache the contact arms to the shorted connections, and then return the board to a horizontal position whereon an encapsulated liquid crystal sheet 5 is placed. While viewing the top of the board via the sheet, the shorted path is energized from underneath using a power supply and the contact arms. The current heats the short and this thermal image is transferred to the sheet. Mounted on the base is a pointer 6 which, when a short is indicated, is clamped in position over the short. The sheet is removed and the pointer remains to indicate the location of the short on the board itself.

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