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

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INSTALLATION AND SOLDERING OF PRINTED CIRCUIT COMPONENTSThe 2M technician should restore the electronic assembly at least to the original manufacturer'sstandards. Parts should always be remounted or reassembled in the same position and with terminationmethods used by the original manufacturer. This approach ensures a continuation of the originalreliability of the system.High reliability connections require thoroughly cleaned surfaces, proper component lead formationand termination, and appropriate placement of components on the board. The following paragraphsdescribe the procedures for properly installing components on a board including the soldering of thesecomponents.Termination Area PreparationThe termination areas on the board and the component leads are thoroughly cleaned to remove oxide,old solder, and other contaminants. Old or excess solder is removed by one of the desoldering techniquesexplained earlier in this topic. A fine abrasive, such as an oil-free typewriter eraser, is used to removeoxides. This is not necessary if the area has just been desoldered. All areas to be soldered are cleaned witha solvent and then dried with a lint-free tissue to remove cleaning residue.Component Lead PreparationComponent leads are formed before installation. Both machine- and hand-forming methods are usedto form the leads. Improper lead formation causes many repairs to be unacceptable. Damage to theSEALS (point where lead enters the body of the component) occurs easily during the forming process andresults in component failure. Consequently, lead-forming procedures have been established. To controlthe lead-forming operation and ensure conformity and quality of repairs, the technician should ensure thefollowing:1. The component is centered between the holes, and component leads are formed with properbend-radii and body seal-to-bend distance.2. The possibility of straining component body seals during lead forming is eliminated.3. Stress relief loops are formed without straining component seals while at the same timeproviding the desired lead-to-lead distances.4. Leads are measured and formed for both horizontal and vertical component mounting.5. Transistor leads are formed to suit standard hole spacing.Lead-Forming Specifications.Component leads are formed to provide proper lead spacing.• The minimum distance between the seal (where the lead enters the body of the component) andthe start of the lead bend must be no less than twice the diameter of the lead, as shown in figure3-13.3-20
Figure 3-13.—Minimum distance lead bend to component body.• Leads must be approximately 90 degrees from their major axis to ensure free movement in holeterminations, as shown in figure 3-14.Figure 3-14.—Ideal lead formation.• In lead-forming, the lead must not be damaged by nicking.• Energy from the bending action must not be transmitted into the component body.COMPONENT PLACEMENT.—Where possible, parts are remounted or reassembled as theywere in the original manufacturing process. To aid recognition, manufacturers use a coding system ofcolored dots, bands, letters, numbers, and signs. Replacement components are mounted to make allidentification markings readable without disturbing the component. When components are mounted likethe original, all the identification markings are readable from a single point.Component identification reads uniformly from left to right, top to bottom, unless polarityrequirements determine otherwise, as shown in figure 3-15. To locate the top, position the board so thepart number may be read like a page in a book. By definition, the top of the board is the edge above thepart number.3-21
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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
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
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 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 128 and 129: 5. The repair is completed using th
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
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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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