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Open Circuit Detector

IP.com Disclosure Number: IPCOM000079606D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 44K

Publishing Venue

IBM

Related People

Kearley, ER: AUTHOR [+4]

Abstract

The Open-Circuit Detector (OCD) of Figs. 1 and 2 is a tool that provides an effective means to isolate discontinuous logic nets in a data-processing machine. The basic components of the tool are a logic card 1, a card extender 2, and input/output signal cables such as 3. Silicon-controlled rectifier (SCR) lamp templates 13 and a carrying case, not shown, are also included. Most efficient operation is achieved when the tool is used on machines after major modifications involving trilead cables and wiring have been performed.

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Open Circuit Detector

The Open-Circuit Detector (OCD) of Figs. 1 and 2 is a tool that provides an effective means to isolate discontinuous logic nets in a data-processing machine. The basic components of the tool are a logic card 1, a card extender 2, and input/output signal cables such as 3. Silicon-controlled rectifier (SCR) lamp templates 13 and a carrying case, not shown, are also included. Most efficient operation is achieved when the tool is used on machines after major modifications involving trilead cables and wiring have been performed.

The tool is used on a machine with power on. It is preferably plugged in a spare location (if available) on the machine board, not shown, having the lamp driver circuits to draw its power (voltage). A lamp driver card 5 is connected to the output of the card 1. This lamp driver controls the console lamps 6, which have the lamp template placed over them for net identification. Also connected to the logic card is the input sensor cable 3. The tool hookup is slightly different on certain machines, the difference being that some machines require an output cable, not shown, be connected between the tool and the lamp driver card.

The sensor cable 3 is normally plugged onto the wire side of the logic boards in the system. The pluggable end of the sensor card is one socket wide and has twenty-four connector pins.

For areas of the board 4 where trilead cabling inhibits use of the OCD on the wire side, the extender 2 is used, as shown in Fig. 1. The machine logic card 12 associated with the board location being tested is removed and plugged into the extender. The extender 2 is then replugged in the board in place of card 12, and the input sensor cable 3 is connected to the opposite side of the extender to couple the OCD logic card 1 and the card 12 to the board pins for testing.

The static voltage level on the board pins such as 8 (Fig. 2) is used as an input to logic 1. Th...