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

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5. The repair is completed using the same epoxy-fiberglass mixture and repair techniques used inthe patching repair method discussed in the following section on burned board repair.Burned Board RepairScorched, charred, or deeply burned boards should be inspected to determine the size of thediscolored area and to identify melted or blackened conductors and burned, melted, or blackenedcomponents. The depth of the damage, which may range from a slight surface discoloration to a holeburned through the circuit board, should also be determined. Damage not extending through the boardmay be repaired by patching (figure 3-28). The following procedure is used in the repair of these boards.Figure 3-28.—Repair of surface damage.1. If the board is scorched, charred, or burned, all discolored board material is removed by abrasivemethods, as shown in figure 3-29. Several components in the affected area may have to bedesoldered and removed before the repair is continued.Figure 3-29.—Repair of burned boards.3-36
2. Repairable delaminations not extending to the edge of the circuit board should be cut away byabrasive methods until no delaminated material remains.3. Delaminated material is not removed if it is repairable.4. After all damaged board material is removed, the edge of the removed area is beveled andundercut to provide holding points for the repair material.5. Solvent is used to clean thoroughly and to remove all loose particles.6. A compound of epoxy and powdered fiberglass is mixed and used to fill the cutaway area.7. The epoxy repair mixture is cured according to the manufacturer's instructions.8. The surface of the filled area is leveled after the compound is cured.9. If delaminations extend to the edge of the board, the delaminated layers are filled completelywith the repair mixture and clamped firmly together between two flat surfaces.10. After the cure is completed, abrasive methods are used to smooth the repaired surface to thesame level as the original board.11. If necessary, needed holes are redrilled in the damaged area, runs are replaced, eyelets andcomponents are installed, and the area is cleaned. Figure 3-30 shows the repaired area ready forcomponents.Figure 3-30.—Repaired board ready for components.Q29. List three causes of damage to printed circuit boards.Q30. What is the preferred method of repairing cracked runs on boards?Q31. Damaged or missing termination pads are replaced using what procedure?Q32. How is board damage caused by technicians?Q33. What combination of materials is used to patch or build up damaged areas of boards?3-37
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NONRESIDENTTRAININGCOURSESEPTEMBER
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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
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Development of a microelectronic de
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Figure 1-9.—Crystal furnace.The c
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Figure 1-12.—Planar-diffused tran
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Figure 1-14.—Vacuum evaporation o
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Figure 1-17.—Cathode-sputtering m
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Q23. How do the two types of monoli
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Figure 1-21A.—TO-5 mounting PLUG-
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Dual Inline PackageThe dual inline
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wafer, as shown in figure 1-27. Thi
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Figure 1-29.—J-K flip-flop discre
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Figure 1-31.—Lead numbering for a
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Figure 1-34.—Manufacturer's Data
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comparison to the distance between
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LEVEL III.—Drawers or pull-out ch
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Conductors located several layers b
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Figure 1-43A.—Evolution of modula
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ENVIRONMENTAL CONSIDERATIONSThe env
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SUMMARYThis topic has presented inf
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Rapid development has resulted in i
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Large DIPs are being used to packag
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MINIATURE ELECTRONICS are card asse
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Three methods of interconnecting ci
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ANSWERS TO QUESTIONS Q1. THROUGH Q5
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A43. Conventional printed circuit b
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Upon satisfactory completion of a 2
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One such improvement in system test
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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
Page 124 and 125: Figure 3-23.—Pcb conductor damage
Page 126 and 127: REPAIRING DELAMINATED CONDUCTORS.
Page 130 and 131: SAFETYSafety is a subject of utmost
Page 132 and 133: OBJECT OR PROCESSWORK SURFACESFLOOR
Page 134 and 135: 8. When moving an ESDS device or as
Page 136 and 137: Power ToolsHazards associated with
Page 138 and 139: dispensers will prevent many accide
Page 140 and 141: A GOOD SOLDER JOINT is bright and s
Page 142 and 143: ANSWERS TO QUESTIONS Q1. THROUGH Q3
Page 145 and 146: APPENDIX IGLOSSARYALLOWANCE PARTS L
Page 147 and 148: MODULAR PACKAGING—Circuit assembl
Page 149: APPENDIX IIREFERENCE LISTCHAPTER ON
Page 152 and 153: Microelectronics—Continuedpackagi
Page 155: Assignment QuestionsInformation: Th
Page 158 and 159: 1-7. Which of the following charact
Page 160 and 161: 1-24. Vacuum evaporation and cathod
Page 162 and 163: ___________________________________
Page 164 and 165: 1-49. Ground planes and shielding a
Page 166 and 167: 1-65. Which of the following types
Page 168 and 169: ASSIGNMENT 2Textbook assignment: Ch
Page 170 and 171: 2-20. Turret, fork, and hook termin
Page 172 and 173: 2-39. Component leads may be clippe
Page 174 and 175: 2-52. To ensure a good mechanical b
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