INTRODUCTION TO SONAR 



and conductors, as set forth in Dictionary of Stand- 

 ard Terminal Designations for Electronic Equip- 

 mentj NavShips 9u0,l86, 



Terminal Boards 



Terminal boards are marked with a 3- or 

 4-digit number preceded by the letters TB. The 

 first 1 or 2 digits of the TB number represent 

 the unit number in the equipment. This number is 

 assigned by the manufacturer in a logical order. 

 The last 2 digits represent the terminal board 

 number in a unit, starting with 01, 02, 03, etc. 

 Thus, terminal board TB 1003 indicates the 3rd 

 terminal board in the 10th unit of the equipment. 



Terminal Markings 



Markings of terminals on terminal boards 

 indicate a specific function for the following 

 circuits: (1) common primary power circuits, 

 (2) ground terminals, (3) common servo and 

 synchro circuits, (4) video circuits, (5) trigger 

 circuits, and (6) audio circuits. The breakdown 

 of these categories into specific functions, with 

 the terminal designation of each, is listed in 

 NavShips 900,186. They are called rigidly assign- 

 ed designations. 



Terminals whose functions do not fall under the 

 categories listed are assigned designations by the 

 equipment manufacturer in accordance with Nav 

 Ships 900,186. They are manufacturer-assigned 

 designations. Only terminals that are connected 

 together externally have exactly the same desig- 

 nation within any given equipment. 



Conductor Marking 



On the conductor lead, atthe end near the point 

 of connection to a terminal post, spaghetti sleev- 

 ing is used as a marking material and insulator. 

 The sleeving is engraved with indelible ink, or 

 branded with identifying numbers and letters by a 

 varitype machine, and slid over the conductor. 



The order of marking is such that the first 

 appearing set of numbers and letters, reading 

 from left to right, is the designation corresponding 

 to the terminal to which that end of the wire is 

 connected. A dash follows the terminal designa- 

 tion, and then the number (without TB) of the ter- 

 minal board towhichtheother endof the conductor 

 is attached. There is another dash and the designa- 

 tion of the particular terminal to which tne other 

 end of the wire is connected. 



Figure 10-6 shows how terminal boards, ter- 

 minals, and conductors are marked. The lower 



^TERMINAL BOARD 



UNIT#d 



SPAGHETTI 

 SLEEVING 



TERMINAL BOARD - 



.CONDUCTOR 

 - ^ W-I0I-2A S lII^I^yB 



TB401 



O 



O 



70.6 

 Figure 10-6. — Conductor and terminal markings. 



portion of the illustration, for example, shows a 

 conductor running from terminal 2A on TBIOI 

 to terminal 7B on TB401. The spaghetti sleeve on 

 the conductor attached to TBlOl is marked 2A — 

 401 — 7B, indicating the other end of the conductor 

 is attached to terminal 7B on TB401. The sleeve 

 at terminal 7B of TB401 is marked 7B— 101— 2A, 

 indicating the other end of the conductor is 

 attached to terminal 2 A on TBIOI. If you must 

 remove a conductor from a terminal, the first 

 set of letters and numbers tells you to which ter- 

 minal it mast be reconnected. 



Cable Marking 



When doing maintenance or repair work, you 

 may have to trace a cable from one section of the 

 ship to another, examining the cable for damage 

 that might be the cause of equipment breakdown. 

 Cables are identified by metal tags that give in- 

 formation on the cable's use. Tags are attached 

 to the cable as close as practicable to each ter- 

 minal connection, on both sides of decks and bulk- 

 heads, and at intervals of about 50 feet. Colored 

 tags formerly were used to classify the necessity 

 of the cable, and you may still see some of them. 

 Red indicated a vital circuit, yellow a semivital 

 circuit, and gray a nonvital circuit. 



The cable designation information is a combi- 

 nation of letters and numters, consisting of a 

 service letter, circuit letters, and cable numbers. 

 A typical cable designation is R—SK3. The service 



160 



