Chapter 9 — MAINTENANCE 



serviceable condition, but they are too numerous 

 to mention in detail here. In some instances 

 these routine checks include electrical measure- 

 ments to check Individual units for malfunctioning 

 circuitry. Technical manuals furnished by the 

 manufacturer include lists of checks to be con- 

 ducted at regular intervals and the desired 

 reading or measurement required for peak per- 

 formance of the specific equipment. 



Cleaning 



Cleaning is an important part of preventive 

 maintenance. External surfaces of electronic 

 units and the surrounding spaces should be 

 cleaned daily. Tills daily routine reduces the 

 amount of dirt and dust that enters the equip- 

 ment through circulating air blower intakes. 

 Some dust and dirt naturally will work their 

 way in, hence the interiors of units should be 

 cleaned carefully at least once a week with a 

 soft cloth. If possible, a vacuiun cleaner should 

 be used. Avoid usingblowers, bellows, or cleaning 

 solvents, because they tend to push or wash 

 dirt into inaccessible corners. If it becomes 

 necessary to use a cleaning solvent, use only 

 methyl chloroform. See NavShips Teclinical 

 Manual, article 67.306 for safety precautions. 

 Air filters should be cleaned at least once a 

 week. Climate and operating conditions may 

 require cleaning more often. Overheating due to 

 clogged air filters often is a prime cause of 

 equipment failure. Neglect in cleaning filters is, 

 therefore, inexcusable. 



Generators must be given a careful cleanli- 

 ness check while the equipment is inoperative. 

 Brushes and commutators should be cleaned 

 frequently. Be cai'eful not to blow or brush carbon 

 dust and other foreign matter into the windings 

 or bearings. When cleaning generators, ensure 

 that the brushes slide freely in their holder and 

 exert proper pressure on the slipring or com- 

 mutator surface. 



Lubrication 



Electronic gear has many parts— such as 

 motors, hoists, gears, and springs — that require 

 regular lubrication. The manufacturer's technical 

 manual should be followed to ascertain where, 

 how often, and how much lubrication is needed. 

 Use caution when lubricating the parts of any 

 piece of equipment, and follow the instructions 

 in the book pertaining to the individual type of 

 equipment. Too much lubrication can be just 

 as harmful as too little. 



CORRECTIVE MAINTENANCE 



Corrective maintenance is another name for 

 repair, and is necessary only after equipment 

 failure. Corrective maintenance usually calls 

 for replacement of internal parts or alignment 

 of electronic components requiring technically 

 trained personnel. Some of this work is per- 

 formed by operating personnel while assisting 

 the technician. As you advance in rate you will 

 perform more highly technical maintenance on 

 your own. 



MAINTENANCE AND MATERIAL 

 MANAGEMENT SYSTEM 



Reliability of electronic equipment depends on 

 the quality of the preventive and operational 

 maintenance received by the equipment. As equip- 

 ment becomes more complex, the maintenance 

 problem becomes ever greater. 



In the past, many programs evolved that often 

 were uncoordinated and sometimes unworkable. 

 The lack of well-trained technicians, together 

 with the large number of reports required by 

 some programs, seriously hampered the main- 

 tenance effort. Overloaded bureaus, moreover, 

 could not properly correlate the mass of informa- 

 tion in the reports. 



To alleviate these conditions, the Standard 

 Navy Maintenance and Material Management (3-M) 

 System was implemented. The 3-M system re- 

 places all other maintenance programs. It pre- 

 scribes standard maintenance procedures and 

 provides a feedback report system that enables 

 the program to be updated, and corrects errors 

 and deficiencies. 



Procedures for managing and reporting the 

 maintenance program are contained in Main- 

 tenance and Material Management ( 3-M) Manual , 

 OpNav 43P2. 



Basic elements of the 3-M system are the 

 Planned Maintenance Subsystem (PMS) and the 

 Maintenance Data Collection Subsystem (MDCS). 

 The PMS provides a uniform system of planned 

 preventive maintenance. The MDCS provides a 

 means of collecting necessary maintenance and 

 supply data, in a form suitable for machine 

 processing. A man-hour accounting system also 

 is used aboard repair ships and tenders in 

 conjunction with the MDCS. As a third class 

 petty officer, you will be concerned with the 

 Planned Maintenance Subsystem and certain por- 

 tions of the Maintenance Data Collection Sub- 

 system. The degree of equipment readiness. 



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