Browse Prior Art Database

Method of Detecting Burned Fuses in Remote Units Under Test

IP.com Disclosure Number: IPCOM000044035D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Kuntz, JJ: AUTHOR [+2]

Abstract

A technique is described whereby a central computer is used to detect defective fuses in circuit boards being tested. With as many as 128 circuit boards under test at the same time, it is essential to isolate any defective CUT (card under test), so as not to damage other CUTs. In the circuit as shown in the Fig. 1, the presence of voltage at each of the CUT power supplies 10 provides input voltage to optocouplers 11 when fuses 12 are intact. Current through couplers 11 causes output voltage at pin 6 to be at near ground potential. Should one of the fuses 12 become defective, current through the corresponding optocoupler 11 will cease to flow. Light-emitting diodes 13 provide the operator with a visual indication of the defective fuse.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 98% of the total text.

Page 1 of 2

Method of Detecting Burned Fuses in Remote Units Under Test

A technique is described whereby a central computer is used to detect defective fuses in circuit boards being tested. With as many as 128 circuit boards under test at the same time, it is essential to isolate any defective CUT (card under test), so as not to damage other CUTs. In the circuit as shown in the Fig. 1, the presence of voltage at each of the CUT power supplies 10 provides input voltage to optocouplers 11 when fuses 12 are intact. Current through couplers 11 causes output voltage at pin 6 to be at near ground potential. Should one of the fuses 12 become defective, current through the corresponding optocoupler 11 will cease to flow. Light-emitting diodes 13 provide the operator with a visual indication of the defective fuse. Output 6 is pulled toward +5 volts by registers 14 which provide a signal to the signal mixer 15, as shown in Fig. 2. During normal testing, a "fuses good signal" 16 conditions signal mixer 15 so that a clear to send signal from serial transmit data 18 will enable data to be transmitted from the interface card 17. During reset operation, a reset pulse is gated at signal mixer 15 with fuse good signal 16, to signal the host that all fuses are intact. When a defective fuse occurs, the reset pulse is prevented from returning. This prevents further testing of the failed CUT but allows testing to continue on CUTs showing fuse good signals.

1

Page 2 of 2

2

[This page contains 6 p...