Navy Electricity and Electronics Training Series - Historic Naval ...

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One such improvement in system testing is the design of a method that can test systems at variousfunctional levels. This allows groups of components to be tested as a whole and reduces the time requiredto test components individually. One advantage of this method is that complete test plans can be writtento provide the best sequencing of tests for wave shape or voltage outputs for each functional level. Thismethod of testing has led to the development of special test sets, called AUTOMATED TESTEQUIPMENT (ATE). These test sets are capable of simulating actual operating conditions of the systembeing tested. Appropriate signal voltages are applied by the test set to the various functional levels of thesystem, and the output of each level is monitored. Testing sequences are prewritten and steps may beswitched-in manually or automatically. The limits for each functional level are preprogrammed to giveeither a "go/no-go" indication or diagnose a fault to a component. A go/no-go indication means that afunctional level either meets the test specifications (go) or fails to meet the specifications (no-go).If a no-go indication is observed for a given function, the area of the system in which it occurs isthen further tested. You can test the trouble area by using general purpose electronic test equipment andthe troubleshooting manual for the system. General purpose electronic test equipment (GPETE) will bediscussed later in this topic. (Effective fault isolation at this point depends on the experience of thetechnician and the quality of the troubleshooting manual.) After the fault is located, the defective part isthen replaced or repaired, depending on the nature of the defect. At this stage, the defective part is usuallya circuit card, a module, or a discrete part, such as a switch, relay, transistor, or resistor.BUILT-IN TEST EQUIPMENTOne type of fault isolation that can be either on-line or off-line is BUILT-IN TEST EQUIPMENT(BITE). BITE is any device that is permanently mounted in the prime equipment (system); it is used onlyfor testing the equipment or system in which it is installed either independently or in association withexternal test equipment. The specific types of BITE are too varied to discuss here, but may be as simpleas a set of meters and switches or as complex as a computer-controlled diagnostic system.ON-LINE TEST EQUIPMENTFunctional-level testing and modular design have been successfully applied to most electronicsystems in use today; however, the trend toward increasing the number of subassemblies within a moduleby incorporating microelectronics will make this method of testing less and less effective.The increased circuit density and packaging possible with microelectronic components makestroubleshooting and fault location difficult or, in some cases, impossible. The technician's efforts must beaided if timely repairs to microelectronic systems are to be achieved. These repairs are particularlysignificant when considered in the light of the very stringent availability requirements for today's systems.This dilemma has led to the present trend of developing both ON-LINE and OFF-LINE automatic testsystems. The on-line systems are designed to continuously monitor performance and to automaticallyisolate faults to removable assemblies. Off-line systems automatically check removable assemblies andisolate faults to the component level.Two on-line systems, the TEST EVALUATION AND MONITORING SYSTEM (TEAMS) and theCENTRALIZED AUTOMATIC TEST SYSTEM (CATS), are presently in production or underdevelopment by the Navy.Test Evaluation and Monitoring System (TEAMS)TEAMS is an on-line system that continuously monitors the performance of electronic systems andisolates faults to a removable assembly. This system is controlled by a computer using a test program onperforated or magnetic tape, cassettes, or disks. Displays are used to present the status of the equipmentand to provide data with instructions for fault localization. Lights, usually an LED, are used to indicate2-4
which equipments are being tested and also which equipments are in an out-of-tolerance condition. Aprinter provides a read out copy of the test results. These results are used by maintenance personnel toisolate the fault in a removable assembly to a replaceable part.Centralized Automatic Test System (CATS)CATS is an on-line system that continuously monitors the performance of electronic systems,predicts system performance trends, and isolates faults to removable assemblies. CATS, however, iscomputer controlled and the instructions are preprogrammed in the computer memory. The status of theelectronic system being monitored by CATS is presented in various forms. Information concerning afailed module is presented on a status- and fault-isolation indicator to alert the maintenance technician ofthe need for a replacement module. If equipment design does not permit module replacement, completeelectrical schematics and fault-isolation procedures will be made available to the maintenance technician.OFF-LINE TEST EQUIPMENTThe Navy has under development an advanced assembly tester designated Naval ElectronicsLaboratory Assembly Tester (NELAT). This tester is an off-line, general-purpose test system designed tocheck-out and isolate faults in electronic plug-in assemblies, modules, and printed circuit boards.Equipped with a complete range of instrumentation, the system allows testing to be accomplishedautomatically, semiautomatically, or manually. In the automatic mode, a complete range of stimuligenerators and monitors are connected and switched by means of a microfilmed test program.The NELAT incorporates modular electronic assemblies that will facilitate updating of the system.The system is designed for use aboard ship. When put into service, this tester will greatly improve thetechnician's capability in the checkout and fault isolation of microelectronic assemblies.Another important system for off-line testing is the Versatile Avionic Shop Test System (VAST).VAST is used in the aviation community for fault isolation in aviation electronics (avionics) equipmenton ships and shore commands with aircraft INTERMEDIATE MAINTENANCE DEPARTMENTS(AIMDs). It is an automatic, high-speed, computer controlled, general-purpose test set that will isolatefaults to the component level.GENERAL-PURPOSE ELECTRONIC TEST EQUIPMENT (GPETE)When no automatic means of accomplishing fault isolation is available, general-purpose electronictest equipment and good troubleshooting procedures is used; however, such fault diagnosis should beattempted only by experienced technicians. Misuse of electrical probes and test equipment maypermanently damage boards or microelectronic devices attached to them. The proximity of leads to oneanother and the effects of interconnecting the wiring make the testing of boards extremely difficult; thesefactors also make drift or current leakage measurements practically impossible.Boards that have been conformally coated are difficult to probe because the coating is often too thickto penetrate for a good electrical contact. These boards must be removed for electrical probe testing.Many boards, however, are designed with test points that can be monitored either with special test sets orgeneral-purpose test equipment. Another method of obtaining access to a greater number of test points isto use extender cards or cables. The use of extender cards or cables makes these test points easier tocheck.Special care should be exercised when probing integrated circuits; they are easily damaged byexcessive voltages or currents, and component leads may be physically damaged. Precautions concerningthe use of test equipment for troubleshooting equipments containing integrated circuits are similar to2-5
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NONRESIDENTTRAININGCOURSESEPTEMBER
Page 3 and 4:
PREFACEBy enrolling in this self-st
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TABLE OF CONTENTSCHAPTERPAGE1. Micr
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Module 11, Microwave Principles, ex
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INSTRUCTIONS FOR TAKING THE COURSEA
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THIS PAGE LEFT BLANK INTENTIONALLY.
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CHAPTER 1MICROELECTRONICSLEARNING O
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VACUUM-TUBE EQUIPMENTVacuum tubes w
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SOLID-STATE DEVICESNow would be a g
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FILM INTEGRATED CIRCUITS are broken
Page 23 and 24: Development of a microelectronic de
Page 25 and 26: Figure 1-9.—Crystal furnace.The c
Page 27 and 28: Figure 1-12.—Planar-diffused tran
Page 29 and 30: Figure 1-14.—Vacuum evaporation o
Page 31 and 32: Figure 1-17.—Cathode-sputtering m
Page 33 and 34: Q23. How do the two types of monoli
Page 35 and 36: Figure 1-21A.—TO-5 mounting PLUG-
Page 37 and 38: Dual Inline PackageThe dual inline
Page 39 and 40: wafer, as shown in figure 1-27. Thi
Page 41 and 42: Figure 1-29.—J-K flip-flop discre
Page 43 and 44: Figure 1-31.—Lead numbering for a
Page 45 and 46: Figure 1-34.—Manufacturer's Data
Page 47: comparison to the distance between
Page 50 and 51: LEVEL III.—Drawers or pull-out ch
Page 52 and 53: Conductors located several layers b
Page 54 and 55: Figure 1-43A.—Evolution of modula
Page 56 and 57: ENVIRONMENTAL CONSIDERATIONSThe env
Page 58 and 59: SUMMARYThis topic has presented inf
Page 60 and 61: Rapid development has resulted in i
Page 62 and 63: Large DIPs are being used to packag
Page 64 and 65: MINIATURE ELECTRONICS are card asse
Page 66 and 67: Three methods of interconnecting ci
Page 68 and 69: ANSWERS TO QUESTIONS Q1. THROUGH Q5
Page 70 and 71: A43. Conventional printed circuit b
Page 72 and 73: Upon satisfactory completion of a 2
Page 76 and 77: those that should be observed when
Page 78 and 79: Figure 2-2.—Low voltage Handpiece
Page 80 and 81: Figure 2-6.—Rotary-drive machine
Page 82 and 83: Figure 2-9.—Pana Vise.HAND TOOLSF
Page 84 and 85: Figure 2-10a.—Pliers.TweezersView
Page 86 and 87: Even though all the items are not u
Page 88 and 89: Figure 2-14.—Stereoscopic zoom mi
Page 90 and 91: other than eutectic, go through a p
Page 92 and 93: A1. Chief of Naval Operations (CNO)
Page 94 and 95: CAUTIONTHIS SECTION IS NOT, IN ANY
Page 96 and 97: The coating material can best be id
Page 98 and 99: Figure 3-3.—Rotary tool conformal
Page 100 and 101: Figure 3-4A.—Eyelets (interfacial
Page 102 and 103: Figure 3-5B.—Clinched leads. SEMI
Page 104 and 105: Figure 3-8A.—Terminals. PIN AND T
Page 106 and 107: Figure 3-8E.—Terminals. SOLDER CU
Page 108 and 109: Figure 3-10.—Solder wicking.This
Page 110 and 111: Figure 3-12B.—Motorized vacuum/pr
Page 112 and 113: INSTALLATION AND SOLDERING OF PRINT
Page 114 and 115: Figure 3-15.—Component arrangemen
Page 116 and 117: Figure 3-16.—Thermal shunt.APPLIC
Page 118 and 119: Removal of Plug-In DIPsTo remove pl
Page 120 and 121: Figure 3-19.—TO mounting techniqu
Page 122 and 123: Figure 3-21.—Flat pack in protect
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Figure 3-23.—Pcb conductor damage
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REPAIRING DELAMINATED CONDUCTORS.
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5. The repair is completed using th
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SAFETYSafety is a subject of utmost
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OBJECT OR PROCESSWORK SURFACESFLOOR
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8. When moving an ESDS device or as
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Power ToolsHazards associated with
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dispensers will prevent many accide
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A GOOD SOLDER JOINT is bright and s
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ANSWERS TO QUESTIONS Q1. THROUGH Q3
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APPENDIX IGLOSSARYALLOWANCE PARTS L
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MODULAR PACKAGING—Circuit assembl
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APPENDIX IIREFERENCE LISTCHAPTER ON
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Microelectronics—Continuedpackagi
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Assignment QuestionsInformation: Th
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1-7. Which of the following charact
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1-24. Vacuum evaporation and cathod
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___________________________________
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1-49. Ground planes and shielding a
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1-65. Which of the following types
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ASSIGNMENT 2Textbook assignment: Ch
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2-20. Turret, fork, and hook termin
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2-39. Component leads may be clippe
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2-52. To ensure a good mechanical b
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