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Circuit Card for Testing Board to Board Cables for Leakage Current

IP.com Disclosure Number: IPCOM000044907D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kurschner, DG: AUTHOR

Abstract

Cables that connect one circuit board to another are tested by removing the circuit cards that are normally plugged into the boards and then substituting cards with a special test circuit. A test card has a latch for each pin of the card, and it has a circuit for setting the latch when a current at a selected threshold level appears at the corresponding pin. A current above the threshold signifies a failure in one of the board to board cables. A number of identical cards permit all of the card positions of one board to be monitored at the same time. A controller is connected to one of the cards by a cable, and the other cards are connected by a jumper from one card to the next.

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Circuit Card for Testing Board to Board Cables for Leakage Current

Cables that connect one circuit board to another are tested by removing the circuit cards that are normally plugged into the boards and then substituting cards with a special test circuit. A test card has a latch for each pin of the card, and it has a circuit for setting the latch when a current at a selected threshold level appears at the corresponding pin. A current above the threshold signifies a failure in one of the board to board cables. A number of identical cards permit all of the card positions of one board to be monitored at the same time. A controller is connected to one of the cards by a cable, and the other cards are connected by a jumper from one card to the next. The controller can signal the cards to reset all of the latches to a non-fault indicating condition, and it can establish the threshold current level at which a latch is set. The controller may have additional cables so that card positions in different boards can be tested.

The cards monitor the pin positions continuously, and the controller reads the card latches in a scanning sequence. Each card has an address, and the controller addresses a particular card by putting its address on the cable. The controller also sends to the cards the address of a particular group of pins for the card. The card then places on the cable the latch output for the corresponding set of pins. The controller masks certain latch positions where...