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

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LEVEL III.—Drawers or pull-out chassis are level III units, as shown in figure 1-36. These aredesigned for accessibility and ease of maintenance. Normally, circuit cards associated with a particularsubsystem will be grouped together in a drawer. This not only makes for an orderly arrangement ofsubsystems but also eliminates many long wiring harnesses. Defective cards are removed from suchdrawers and defective components are repaired as described in level II.LEVEL IV.—Level IV is the highest level of packaging. It includes the cabinets, racks, and wiringharnesses necessary to interconnect all of the other levels. Other pieces of equipment of the same systemclassified as level IV, such as radar antennas, are broken down into levels 0 to III in the same manner.During component troubleshooting procedures, you progress from level IV to III to II and on to level0 where you identify the faulty component. As you become more familiar with a system, you should beable to go right to the drawer or module causing the problem.Q40. Resistors, capacitors, transistors, and the like, are what level of packaging?Q41. Modules or submodules attached to a mother board are what packaging level?Q42. What is the packaging level of a pcb?INTERCONNECTIONS IN PRINTED CIRCUIT BOARDSAs electronic systems become more complex, interconnections between components also becomesmore complex. As more components are added to a given space, the requirements for interconnectionsbecome extremely complicated. The selection of conductor materials, insulator materials, and componentphysical size can greatly affect the performance of the circuit. Poor choices of these materials cancontribute to poor signals, circuit noise, and unwanted electrical interaction between components. Thethree most common methods of interconnection are the conventional pcb, the multilayer pcb, and themodular assembly. Each of these will be discussed in the following sections.Conventional Printed Circuit BoardPrinted circuit boards were discussed earlier in topic 1. You should recall that a conventional pcbconsists of glass-epoxy insulating base on which the interconnecting pattern has been etched. The boardmay be single- or double-sided, depending on the number of components mounted on it. Figures 1-37 and1-38 are examples of conventional printed circuit boards.Multilayer Printed Circuit Board.The multilayer printed circuit board is emerging as the solution is interconnection problemsassociated with high-density packaging. Multilayer boards are used to:• reduce weight• conserve space in interconnecting circuit modules• eliminate costly and complicated wiring harnesses• provide shielding for a large number of conductors• provide uniformity in conductor impedance for high-speed switching systems1-36
• allow greater wiring density on boardsFigure 1-39 illustrates how individual boards are mated to form the multilayer unit. Although allmultilayer boards are similarly constructed, various methods can be used to interconnect the circuitryfrom layer to layer. Three proven processes are the clearance-hole, plated-through hole, and layer buildupmethods.Figure 1-39.—Multilayer pcb.CLEARANCE-HOLE METHOD.—In the CLEARANCE-HOLE method, a hole is drilled in thecopper island (terminating end) of the appropriate conductor on the top layer. This provides access to aconductor on the second layer as shown by hole A in figure 1-40. The clearance hole is filled with solderto complete the connection. Usually, the hole is drilled through the entire assembly at the connection site.This small hole is necessary for the SOLDER-FLOW PROCESS used with this interconnection method.Figure 1-40.—Clearance-hole interconnection.1-37
Page 1 and 2: NONRESIDENTTRAININGCOURSESEPTEMBER
Page 3 and 4: PREFACEBy enrolling in this self-st
Page 5: TABLE OF CONTENTSCHAPTERPAGE1. Micr
Page 8 and 9: Module 11, Microwave Principles, ex
Page 10 and 11: INSTRUCTIONS FOR TAKING THE COURSEA
Page 12 and 13: THIS PAGE LEFT BLANK INTENTIONALLY.
Page 15 and 16: CHAPTER 1MICROELECTRONICSLEARNING O
Page 17 and 18: VACUUM-TUBE EQUIPMENTVacuum tubes w
Page 19 and 20: SOLID-STATE DEVICESNow would be a g
Page 21 and 22: 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 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 74 and 75: One such improvement in system test
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
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Figure 3-5B.—Clinched leads. SEMI
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Figure 3-8A.—Terminals. PIN AND T
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Figure 3-8E.—Terminals. SOLDER CU
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Figure 3-10.—Solder wicking.This
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Figure 3-12B.—Motorized vacuum/pr
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INSTALLATION AND SOLDERING OF PRINT
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Figure 3-15.—Component arrangemen
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Figure 3-16.—Thermal shunt.APPLIC
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Removal of Plug-In DIPsTo remove pl
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Figure 3-19.—TO mounting techniqu
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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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Navy Electricity and Electronics Training Series - Historic Naval ...

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