Manual / Guide · 1961
Technical Bulletin 565: General Maintenance of P-A-X's
Routine maintenance of small AE private exchanges.
Manual / Guide · 1961
Routine maintenance of small AE private exchanges.
\1 I I -·., rr I J ' ~ ,, I ' .I I ' ·I I I I, I '/' \ 1l ,. ' ,. \ ' ,. -:, I I ' J 1 fl \ v I I I' 11 'I I " ! ; l . y ;, b ' x \. v' I I' ,/ I r · 1 _, j 1 • I ,- /' \ •1 .{ . I'· /. \ ; ) 1, ' \-' v.\ / > / 1\ _) -1' I 1 I, ,l I . /,' I I/,; i '· t· 'i I 1, '1 '-. .1 / ' I ,I 1, rI ,\' ., / 1/ I r t' I ' .( I t ~. l' I 'I I l I\\ 1, I •' \ )', ,, I I)~- ,. '11, j \( 'I \ I ,~ '~ t ; 1, \, '1 11 ,/ I 1\ I \ - 'I \1, ' I I ,l { ,., J //' f " ' J t·' I ,, r , ~ ' "' c~ '\ I .'9. [' I·, " Ii I .. '\· ri-; ( \· ) \ \~ I -~ TCI Library www.telephonecollectors.info '' I j' '! ," ( \ I . :;/ ,\ ' rr. '"(~'' . l -·· ,,..,. 1' • "v.~._, ./! !\,/K ( \' ~'" / ~ " ' / ' I '-1 / ;./ / ( ' ' * ,. ' } 1 \t\ ( \' (' I ' !., t ,.. .( ,-r ~ ,, '- \ \ j \ '' \ f ~J "' I~ • . . I ' ' \ I ~ I }.J·~ ' ·,,. ,..;.-' \ rI ' \ t' ; , ; I ' "' ' . "' '; j (' J 'I I ' , ''I -P:.J ~\ J ~· f ,J (•. :<;, > '( t < l\. I. ' , Factory,) deqelopme~ laborptories, and gen-erpl <!ffice ar;;:..Norihlake, ' \ · , 1I .l '" "· \ ,, ~ t.• ,!'_ ~ J / '· _, , } AUTqMATIC ELEC'fRIC C,OMPANY i& an J6r'g~1uzation ?f qesigning, engineering, and '-. 1 manu(actur.ing'specialists intthe field& of comtmuni~ation, ~lectrical control, and allied arts. Fp~ mor~ tf1an sixty years tlie company ,has ·bee~ known ~hrouj;hout ~he wor,ld 4s t.)1~ originator a.n<l parer\.t · mai1ufactuter of tli.,e.- Sti;ow~er Autli>mati.c Telephon~ System. Today Strowgei;-type equipm~n~ serves over 7So/o of' the- world's ,autom;i.ti~ telephones. T.Qe same experience and technique that 'have grown 1out: of the ~work of Autonl,atic Electrfc ' engineers i[t th,e' fi~lcl of tef~phone e~nU'nuni~ation are a's~ ·b~iµg suc~s~fully applied ,pn ~l'l · ever-increasing s~ale- to the so'lutioft of el~ctri<;al co~trQl; pn,ib]ems- in husiness<an~ industr~. 1,, / I 'r l > ,..., /' , I ' ;;: • fo / ,\ PR~IPAL ~PRODU(:TS ' ( ' - . ~on~'ecti<tns, 11nd with faeilities for speci~l control ( services to meet ffie needs -0£ tbe user. 1 change uea.1 of any< size, froni small towns to th«; largest)11etropolitan ntlWo~ks., ,_' / I . P.B:X._ Switdiboards-A complrte range of cordless and <·o):d types for the inodern 1:i.1sjness. \ , \ ·..? r - '· . \.'l ~~ ,,, > 1 ' ' ...I .. ' L I ~ / ,I - I J->i • . //'"' -- / ....., r- '( J • 1, ., (i \ f \ \ j I 'lJ I ~ > .r _.,.> ,, L \ \ ',.. ' '\ • 11 ./ ·' /\ t - . . I \ I .' ' ( 0'k ' \ , I ' '' ' J - \ • __y "" \,... ' ' '\ ·,. ' ') ..j j,.. .•.: l ' - '" I / \ I / I ,/ / '" ' ( Copyright © 1 19\6~ 1 Automatic ·Electric. pompany ./ I . ' I . I I... I '.1>-: , f ~1l- I y. I ,.,__ \ t' . l I '' / / ' ' ~ ,' autornatjc or manual exchanges., inclt1ding the ' I ;.,. MonophoQ-O-the world's most attractive .and em· 1 t~lephone: dent handset ' J' ..,. 1 ' ,, , / . ' I ,.. , j>- )' ., } Tel~phone _ln~trumflnls -,Modern desig,ns fo1:. I . i' Makers .also pf,ele<-tri(1al co..;tro apparatus for industri~, .~ineering, ai•d 'prblic -"' u~i'y companie5, telephone app8,ratus for railroads and nipe-line rQmpanle.i;, {1rlvate telephone _s:Vstems of Ml ~ypes,' electric;11,l anf\ ~mmunication tf~vices (or • ~ircra£,t and air~a:v( control, ;an,~ ~pecial coDl(lnunicafion !!P~aratqs for milif~y I ' ~nd naval depar'tpient~. .t .,... ' \ 1 \ ,,, ·( , Alutomafi~ ~oil Bo11rdst':A n. adaptatirn ~f . Exchange 1 Accessor:y Equip~nent -A µJtiliary ,exStrowger:-'prmclJ.ll~s ,to toll sw1tchmg, resulting m change '.{li1d &uhsiat(op equil?,meJ"(• itH'l~dihi;\ simplififation of opera!ors' eqµjpme~t and greater -::C_ / manual de.sk.s, - test<inig .app'a ratus, tra;isn1iss,ion economy' qf opt:rating a'riJ, toll-1·ircµi( titn"e. _ · ,_ equipnient, and all a.cces~o.iies ne.ed~13or the Private Aut•oma-ti'< Ex1;han-ge.s.1:Available in operation ' and 111aipte11anee Qf the. 1uodern teJe.v~rious rapacities, )V'ith .Qr "'id;'out central-offi~e phqn_e exchange. .,; ; ' l ,/ ,, f -· j· Strowger Automattc Tek!phon,e Systef1u-<;:om· 15-, 'plt:te allto~natic cen~rariffi•~e equipment ' for ex· , r . ' •• ,/ ,,. \. Commwiity, Arttdmatic Exchangu-Una~tel'jded automatic un.its .for s1~iaJI rural.,or suburban ueas,1 .' wi'th fa.c1Jities for SWit<)iingintO attended ' I ' .. ' I > I ' ' ' '· excJ:ianges. · ,.I I ~ I ~,... ; _.,- I ' r \ / '. I' /' I· ,I ..... /I ·~ TCI Library www.telephonecollectors.info r ~I ) J ( " ., ,. /.' <' ' ... ' ~\ ( •' TABLE OF CONTENTS Page Section 1. 2. INTRODUCTION. 1 1. 1 1. 2 1. 3 1. 4 1. 5 1 1 1 Scope of Publication . P-A-X Equipment Station Equipment The P-A-X Building Wiring . 4 TOOLS AND TEST MATERIAL 5 2. 1 2. 2 2. 3 5 5 2 Tools . Maintenance Materials Hand Test Telephone 5 6 3. LUBRICATION 4. PREVENTIVE MAINTENANCE 6 4. 1 4. 2 6 6 5. 8 5. 1 8 10 10 10 11 11 5. 3 -5. 4 5. 5 5.6 7. 8. 9. Maintenance Procedures Performing Preventive Maintenance STATION SUBSCRIBER COMPLAINTS 5. 2 6. . Classes of Complaints Class 1 Complaints Class 2 Complaints . Class 3 Complaints . Class 4 Complaints . Investigation of Complaints and Correction TROUBLE SHOOTING 17 6. 1 6. 2 6. 3 6. 4 6. 5 17 17 General General Notes Using the Test Lamp Using the Ground Cord Testing Tone and Ringing Circuits 18 21 21 REMOVAL OF COMPONENTS AND PARTS • 21 7. 1 7. 2 7. 3 7. 4 7. 5 7. 6 7. 7 . . 21 21 22 23 25 25 25 Removal of Line switch . . Removal of Strowger Switches . Relay Removal Type 45 Rotary Switch Removal Lamp Removal Fuse Removal . . . . . . Alarm-indicating Power Fuse Repair. . PERIODIC INSPECTION AND READJUSTMENT OF RELAYS AND SWITCHES . ROUTINE TESTS 27 • TCI Library www.telephonecollectors.info 30 FINDER SWITCHES (FRS) CONNECTOR SWITCHES (CRS) COMMON LINE AND DISTRIBUTION RELAYS (CLAD) -~~L..;.;~ RINGING INTERRUPTER ---~~~Iii RINGING CONVERTER TONE EQUIPMENT FINDER CO NNECT OR LINKS ( FC LINK ) TONE TRANSFORMER TEST BINDING POSTS RINGING TRANSFORMER AMMETER VOLTMETER 24 VOLT BATTERY CHARGER Fig ure 1. Typical rotary -typ e P-A-X . TCI Library www.telephonecollectors.info GENERAL MAINTENANCE OF P-A-X's 1. INTRODUCTION All Privatf' Automatic Exchanges (P-A-X) manufactured by Automatic Electric Company :1.r0 ruggt·'dly constructed (figure 1), designed for long use, and require very little attention. ;\ :-,u .. i!: amount of maintenance is required at n·guL.u· inter vais lo forestall possible service int nTuptions. Minor defects can be detected •.L1d cc;rrcC'ted before they develop into a service e:ompla int. Thih puf>lica ti.on is directed pl'imarily toward personnel who maintain the rotary ;:;witch and relay switching components of the i'"A-'<. i .1 S·.·ope of F'ublication This publication includes maintenance instructions for all components of all P-A-X's. Instructions for cleaning, adjusting, removing, and repairing relays and rotary switches are applicable to a majority of the components and therefore are given only once. For detailed theory of operation of your P-A-X, refer to the technical bulletin supplied with the equipment. 1 .2 P-A- X Equipment An isolated dial telephone system consists of three distinct components as shown on figure 2. a. The first component is the station equip·ment which is designated as the "A" equipment. "A" EQUIPMENT b. The second component is the P-A-X equipment which is designated as the "B" equipment. c. The third component is the building wiring which is designated as the "C" equipment. 1.3 Station Equipment rr11e telephone, designated as the ''A" eq11ipment in figure 2, is represented in figure 3. With the handset on its cradle, the hooks witch places the ringer and its associated capacitor in series across the line, or from one sidf~ of the line to ground when party line service is required. The capacitor blocks the flow of the d-c switchboard battery in the ringer coils to prevent a shorted or ''permanent'' line. However, the P-A-Xringingconverter supplies a 20-cycle signaling source which flows through the capacitor to operate the station ringer and signal the called party. This ringing current is supplied over the (+)side of the line, through the ringer coils and capacitor, to either ground at the instrument or back over the (-) side of the line to the P-A-X (-) battery and ground through the· ringing relay. Removal of the handset causes the hookswitch to open the ringer circuit, and the ringing cut-off relay of the P-A-X conversation link operates to stop the ringing. To make a call, remove the handset. This places the dial pulse springs in series with the •a• EQUIPMENT "c" EQUIPMENT + ISOLATED DIAL TELEPHONE SYSTEM Figure 2. Isolated dial telephone system. TCI Library www.telephonecollectors.info 1 HANDSET TRANS UNIT DESK I STAND TERM. BLK. IMPULSE SPRINGS LI • TRANSMITTER . x·r----0---... HDOKSWITCH •z• 'i RINGER 4 G \ USE "z" WIRING FOR BRIDGED RINGING Fi/,7tre 3. Typical wiring diagram of a tcleplw11e set. transmitter across the line to the P-A-X, completing a d-c loop. The switchboard equipment is seized, dial tone is heard, and the desired number can be dialed. While in its off-normal position, the dial shunting springs will short-circuit the transmitter to prevent dial clicks in the receiver and also to prevent the variable resistance of the transmitter from affecting the dial pulses. The dial pulse springs interrupt the circuit to the P-A-X a number of times equal to the digit dialed to select the desired party. The equipment is released when the handset is restored. This is the general operation of the telephone. A detailed wiring diagram is located inside the assembly and, with it, each wire can be traced and identified. No special tools are required for repair except a screwdriver and a pair of dial pliers. closes the circuit to the line relay by lifting his handset, the relay operates and starts the linefinder hunting for an idle connector. In some P-A-X's, a lineswitch is used in place of a line relay and line finder. In this instance, the subscriber lifts his handset and closes the circuit to a lineswitch. The lineswitchoperates automatically and connects the calling line to an idle connector trunk. A lineswitch is required for each station. The functions of a lineswitch are: a. To extend the line through to an idle connector trunk. b. To busy the line at the connector bank terminals to incoming calls immediately upon operation of the line switch relay. c. To restore itself to normal when the connector is released. 1.4 The P-A-X The P-A-X designated the "B" equipment in figure 2, consists of the following three interrelated components to form a switchboard (see figure 4). 1.4.1 The individual line equipment. This group of identical units, required for each telephone line, consists of line relays. The two wires from each telephone terminate in the switchboard at a line relay. When a subscriber 2 The type 27 plunger lineswitch used in some P-A-X's consists of a line relay and an opera ting coil which activates an armature carrying a plunger. Details of the type 27 lineswitch are fully described in bulletin 805, copies of which will be furnished upon request from Automatic Electric Sales Corporation. 1.4.2 Conversation links. The conversation links consist of linefinders and connectors. The number of each depends TCI Library www.telephonecollectors.info on the size of the P-A-X. The linefinder and its associated connector form a linefinderconnector link (conversation path). a. The linefinder. Some P-A-X'susearotary type linefinder while others use a Strowger type. When a linefinder is seized, it hunts for and connects an idle connector to the calling party line. At this point, circuit operation causes the distributor switch to advance its wipers ahead to the next idle link. The mechanical components of a Strowger linefinder include a shaft, and a ratchet mechanism for raising and rota ting the shaft. Its electrical components include control relays, vertical and rotary stepping magnets, and a magnet which releases the ratchet mechanism. b. The connector. Under guidance of the calling party. the connector functions as an operator via the telephone dial. Connectors used in P-A-X's are the Strowger type and in some cases the rotary switch type. The Strowger type connector's mechanic a 1 components include a shaft, a ratchet mechanism for raising and rotating the shaft, and two sets of wipers (termed the line and control wipers). Its electrical components include several control relays, vertical and rotary stepping magnets. and a magnet which releases the ratchet mechanism. The bank contacts at the bottom of the connector are the terminals of the t e 1 e phone lines which the connector serves. Each contact is multipled to each connector bank so that all connectors can have access to any of the telephone lines. In response to dial pulses, the connector raises its wipers to the dialed level and across to the dialed level contact which is the called party's line. When the connector is released, the switch shaft is restored to its normal position. The connector functions are: ( 1) Upon seizure. to hold equipment behind and busy out the calling party's line. COMMON EQUIPMENT DISTRIBUTOR SWITCH - - - - - - - - - - - TONE RELAYS RINGING EQUIPMENT DISTRIBUTOR RELAY GROUP FROM CALLING STATION - - - - - - - - - - - I N T E R R U P T E R EQUIPMENT =-i LINE CONNECTOR ANQ I CORLY FINDER SWITCH TO DIST RLY GRP LINE AND CORLY TO CALLED STATION TO FINDER SWITCH BANKS INDIVIDUAL EQUIPMENT CONVERSATION LINKS INDIVIDUAL EQUIPMENT Figure 4. Schematic of a dial system. TCI Library www.telephonecollectors.info 3 (2) To start and stop the switchboard common equipment as required. d. Ringing interrupterso An a-c so11rce is interrupted and delivered to the connectors for ringing the called telephone lines. P. The tone relay and interrupter. A portion of the P-A-X power supply is converted into a steady dial tone or interrnp!ed husy tone and is supplied totheca!lingpartyvia the connector as required. f. Supervisory alarm equipment. The signal larnps and associated relays of the P-A-X supervisory alJi·rn ~';\1:,:tcrn arc found on the individual apparcttw; shelves which they supervise. A buzzer provides a general alarm to all shelf units. The supervisory aL1nn equipment operates as follows: (3) To return a husy tone to the calling party when the dialed line is busy. (4) To ring the called party's telephone and return ring-back tone to the calling party. (5) To stop ringing when the called party answers and supply talking battery for both parties. ( 6) To release after the calling party has restored his handset. (7) To prepare the release alarm signal if the mechanism fails to reston~ properly. (1) Power-supply shelf. A glowing rc!d lamp indicates a blown fuse. !\ glowing white lamp indicates the failure of the charging equipment to deliver current to the storage battery (if any) when the charge control relay operates. 1.4.3 Common equipment. a. b. c. 4 Distributor group. The distributor group is a switch consisting of control relays [or· the lirwfinders and a rotary switch. The distributor switch preselects and assigns dialing links successively to incoming calls. Only one distributor switch is needed. After a previously assigned link has been seized, il irnmedialely allots the next idle link for another incoming call. The di8trihutor switch passes over bank contacts of busy links. When all links are in nsr:, th0 dis l.r :bu tor· switch rotates to its home position rt'ady to advance inunedi<.L tely to thv bank contacts of the first link to become idle. Master switch. When a plunger type lineswitch is used in place of line relays and linefinders, the common equipment consists of a master switch instead of the distributor group. The position of the plungers of each group of lineswitches is controlled by a mechanism termed a master switch. The control is through the movement of the plunger guide shaft. The prime function of the control is to keep the plunger of all idle lineswitches resting opposite the bank contacts of an idle trunk. Each time a trunk is engaged, the master switch immediately moves all the remaining idle lineswitch plungers to a position opposite an idle trunk. The plunger type lineswitch is thus preselecting in operation; that is, the idle trunk is selected prior to a call. Ringing converter. A portion of the P-A-X power supply is converted into an a-c source for operating the telephone ringers via the connectors. (2) Lineswitch shelf. A glowing red lamp indicates a blown fuse. A glowing white lamp indicates that all lineswitch trunk outlets are busy. (3) Connector shelf. /\ glowit1g red lamp indicalPs a hlown fiisc. ;\ ~~lo1Aing g-r0en larnp indicates the failu1·cofar. CH1rw··'.rn· tn release. g. The power control panel. The power control panel ordinarily includes a voltmeter for determining the potential of the power supply, an ammeter for determining the load on the switchboard, a charge and discharge fuse, and a number of alarm fuses. h. Power supply. Normally a battery eliminator is used and is supplied with the P-A-X when specified. This apparatus draws alternating current from a standard 110 volt a-c outlet (or from a 220 volt, a-c outlet) and converts it to direct current. In some cases, a battery is used (dry cells or wet cells). When wet cells are used, a battery charger should be used with the battery and is supplied when specified. 1.5 Building Wiring The building wiring, designated as the "C" equipment of figure 2, consists of all facilities used to connect the station equipment to the P-A-X. This portion of the telephone system, that is any electrical circuit, should be kept dry. TCI Library www.telephonecollectors.info 2. TOOLS AND TEST MATERIAL 2 .2 Maintenance Materials This section lists the tools and materials required for maintaining a P-A-X. The manufacturer's part number is stamped on most of the tools to help identification. Technical bulletin 5 40 lists all maintenance tools and contains tool illustrations which are referenced below. The most commonly used maintenance materials required for general maintenance of a P-A-X are as follows: 2 .1 Tools H-880843-1 TABLE B: A. E. Co. Number The tools generally required to properly maintain P-A-X equipment are listed below: TABLE A: A. E. Co. Number P-A-X EQUIPMENT TOOLS Item D-542539-B Use P-A-X MAINTENANCE MATERIALS Item Use No. 4 Sable Brush Lubricati on. 1/2" Camel's Hair Brush Relay dusting. Cheesecloth Cleaning exterior Oiled Sleeving Switch bank cleaning Orange Stick General. Solder General repair. Tape, TL-83, 3/ 4" General taping. Twine 8 and 11 Play Cable repair. Bank Cleaning Brush Strowger switch banks. H-14768 Armature Adjuster Relays with shortlever armatures. H- 88502- 1 Armature Adjuster Relays with longlever armatures. H-88504-1 Spring Adjuster Relays with stationary springs. 1{-88504-2 Spring Adjuster Relays with moving springs. H-882553-1 Contact Cleaner Cleaning relay contacts. H-882568-2 Lamp Extractor Removing switchboard lamps. H- 883114- 1 Lamp Cap Extractor Removing lamp caps. 2 .3 Hand Test Telephone H- 14315- 1 Fuse Repair Kit Repair of alarmindicating fuses. H-46795- 1 Thickness Gages Residual screw adjustment. H-16339-1 Test Lamp For 48v de continuity tests. H-880922-1 Inspection Lamp Gaging of relay contacts. H-50619 Long Nose Pliers General usage. H~22945 Diagonal Cutting Pliers General usage. The basic hand test telephone designed for station repairmen is the A. E. Co. No. L-965. The L-965-A2 (figure 5) hand test telephone is the basic L-965 with a test cord and two test clips attached that can be snapped onto line wires, terminal screws, and ground connections (such as a cable-terminal box), etc. The L-965-AO hand test telephone is equipped with a test plug which can be inserted into Strowger switch test jacks. H-50620 Duckbill Pliers Rotary switch interrupter and wiper adjusting. H-16290- 7 Dial Pliers Spring adjusting. H-21766 Offset Screwdriver Air gap adjustment. H-24664 Screwdriver General usage. H-7062 Open-end Wrench Residual screw lockout. H-7063 Open-end Wrench For adjusting rotary switches. TL-117 Soldering Iron General usage. H-56628-4 Cleaning Tool Rotary switch banks. H-16590-1 Cleaning Tool Strowger switch banks. H-26917 Dial Escutcheon Tool Dial disassembly. H-74573-1 Ground Cord Verifying open d-c circuits. H-88844-1 TCI Library www.telephonecollectors.info Figure 5. Hand test telephone. 5 3. LUBRICATION has not become damaged, and that soldered connections are in good condition. The purpose of lubrication is to provide a film of lubricant between fixed and moving or two moving surfaces to reduce friction and wear. Avoid excessive lubrication, since too much lubricant can be just as harmful as not enough. Remove any excess lubricant by wiping. All components that require periodic lubrication are listed in technical bulletin 505. c. Cleanliness. Examine carefully all recesses in the unit for accumulation of dust, especially between the connecting termi-· nals. Parts, connections, and joints should be free of dust and other foreign matter. d. Tightness. Any connection or mounting that appears to be loose should be checked. Screws, nuts, and bolts should not be tightened carelessly (fittings tightened beyond the pressure for which they are designed will be damaged or broken). Do not confuse the adjusting screws with mounting screws. Perform cleaning operations carefully, in order not to damage the equipment or change its adjustment. e. Lubrication. Observe the amount of lubricant on all moving parts requiring lubrication. 4.2 Performing Preventive Maintenance 4. PREVENTIVE MAINTENANCE Preventive maintenance consists of a series of routine inspections which provides insurance against operational failures and major repairs. These routine inspections are a systematic series of operations performed on equipment at regular intervals. They are designed to eliminate major breakdowns and unwanted interruptions in service and to keep the equipment operating at top efficiency. The inportance of preventive maintenance cannot be overemphasized. Preventive maintenance differs from repair in that it is intended to prevent breakdowns, and therefore, eliminate the need for repair. On the other hand, the prime purpose for trouble shooting and repair is to locate and correct existing faults. 4.1 4.2 .1 Inspection. Inspect all units regularly to prevent needless interruptions in service. Maintenance Procedures Check: Most of the electrical and mechanical parts used in P-A-X systems (equipment) require routine maintenance, but differ in the amount and kind required. The age of tht' equipment and the conditions under which it must operate govern the frequency of maintenance tests and inspections. An accurate fault statistics file will show whether preventive maintenance is applied properly. A person performing maintenance on P-A-X equipment should become thoroughly familiar with the indications of normal functioning so that he can recognize the first signs of defective equipment. To detect minor defects and signs of worn, damaged, or corroded parts which may later cause trouble, a visual periodic inspection should be made. Although these minor defects may not have interfered with the performance of the equipment, correcting them before they lead to major breakdowns saves valuable time and effort. Periodic inspection consists of observing all parts of the equipment during operation. It is advisable to inspect for the following conditions: a. Overheating. Look for discoloration, blistering, or bulging of the parts or surfaces of a cover, leakage of insulating compound, and oxidation of metal contact surfaces. b. Placement, See that leads and cabling are in their original positions, that insulation 6 a. Relay coils and rotary switch coils for discoloration, blistering, and bulging. b. Transformer and choke coils for discol oration1 blistering, and bulging. c. Contacts for oxidation, pitting, dirt, dust, and lint. In high humidity locations, look for fungus growth and mildew. d. Covers, cables, leads, and individual parts to see that they are in their original positions, securely fastened, and are not frayed or broken. 4 .2 .2 General office care. a. Keep dirt, dust, and moisture out of the P-A-X room. Dust and dirt cause excessive equipment failures, since it eventually filters into the working parts. Moisture and humidity also cause equipment failures through rust and corrosion of metal parts, or electrolysis and insulation leakage in electrical apparatus. Keep all parts of the room as clean as possible. Linoleum or similar floor covering is desirable. Keep it lightly waxed and clean it at regular intervals with a mop dampened lightly with water. For rooms without floor covering, use a push broom and sweeping compound. Remove accumulated dust and TCI Library www.telephonecollectors.info dirt from the equipment with a clean, lintfree cloth. Use a camel's hair brush to remove dust from relays or switchassemblies where space is limited. b. Ventilation. Outside air drawn into the P-A-X room must be passed through filters. Only filtered, dust-free air should be circulated in the room. Seal all windows, unnecessary doors or other openings to prevent entrance of dirtbearing, unfiltered air. Inspect the air filters frequently. The use of air conditioning eliminates the need for outside ventilation. c. Humidity. When high humidity prevails, the equipment must be protected from moisture damage. Relative humidity, an expression for the moisture content of the air, is the ratio of moisture actually present in a given volume of air compared to the maximum which the air can evaporate and hold. Heating the air increases its capacity to evaporate and hold moisture and, therefore, reduces the relative hllmidity. When air cools, its capacity to hold moisture is reduced, causing its relative humidity to rise. If warm moist air comes in contact with cold equipment, the sudden cooling causes it to deposit its moisture in the form of dew. To avoid moisture troubles, keep the relative humidity below 60% and never above 70%. Use hygrometers, one indoors and one outdoors, to provide accurate readings of humidity conditions. d. e. Air conditioning. A unit type air conditioner, using a refrigerated cooling system, provides the most effective protection against high humidity. Air from the P-A-X room is circulated over the cooling coils, giving up its moisture, and is returned to the room through a dust filter. The resultant dry, dust-free, and cooled air insures the best equipment performance. For the very small P-A-X's, there is available a unit type chemical dehumidifier which will reduce the content of moisture in the air without the use of a refrigerated cooling system. Battery. Wipe the battery jars, connections and surrounding parts with a dry cloth. If the terminals or connections are corroded, scrape clean, wash them with soda solution (one pound of bicarbonate of soda to a gallon of water), dry, and coat them with a thin layer of vase line. Add distilled water to the batteries as required to maintain the proper electrolyte level within the cells. See the manufacturer's literature for complete details of battery care. f. Relay contacts. Clean dirty relay contacts with a fast drying fluid, such as alcohol or chlorothene, before being polished. Carbon tetrachloride is not recommended. Clean the contacts with contact cleaning tool H-882553-1 or a similar cleaner. Never use a rough-surfaced object for contact cleaning as it will remove contact material. Do not use cloth or paper as a substitute for the contact cleaner, since both have insulating lint on the contact surface. Clean or polish the contacts by holding adjacent contacts together and running the cleaner between them several times. g. Rotary switch contacts. Rotary switch bank contacts are designed so as not to require any lubrication or cleaning for the life of the switch. In the event that it becomes necessary to replace a wiper assembly, the bank contacts should be cleaned as a preventive measure before replacing the assembly. Use bank cleaning tool H-56628-4 with an. oiled sleeving. Rotate the tool between the rows of the bank contacts. Clean the outside of the two outside rows by gently pressing the tool toward the center of the bank while rotating the tool. After cleaning, lubricate the wiper tips. h. Cleaning and oiling of Strowger switches. Busy out the link associated with the connector during cleaning or oiling. Clean and oil the bearings, shaft, and the vertical and rotary teeth at least once a year. Use lubricating material supplied with the installation. Clean the release magnet coil core and armature. Brush off the conrtector bank contacts with bank cleaning brush H-88844-1 or 2. Clean and oil Strowger switches once a year with cleaning tools H-16590-1 or 2 and the oiled webbing supplied with the P-A-X. Do not damage the bank insulators and switch wipers. Keep bank collars in place and bank nuts tight. The banks must not drop down on their bank rods. 4 .2 .3 The building wiring. The following is a list of suggested wire maintenance practices. a. Do not make temporary repairs. Replace defective material. b. Terminal box connections must be tight. Wire insulation should be brought up to the terminal lug to prevent shorts with an adjacent wire. c. Label terminal box strips to identify the circuit contained therein. Note changes so others can find the trouble. TCI Library www.telephonecollectors.info 7 d. Splices should be made and taped carefully. Poorly made splices cause trouble. A void splicing building wires placed in conduit runs. A corrected comparison. dial may be used as a (6) Clean and adjust the shunt and pulse springs (see figure 3). To clean, use the contact cleaner H-882553-1, and to adjust use the dial pliers H-16290-7. Shunt springs are closed while the dial is off normal. The cam does not open the pulse springs until its final half revolution. e. Spare pairs should be included in conduit runs to facilitate additions or replacements in the existing system. f. Protect the exposed sections against damage, especially at the instrument terminal block. b. Leave enough slack at each end of a twisted wire pair to eliminate the need for splicing when the telephone is relocated. The ringer. Check for loose parts. Adjust the gongs to improve tone. See that the bias spring is in place. Check for loose or shorted connections. c. The hookswitch. Clean and oil for smooth operation. Clean the spring contacts with cleaner H-882553-1. A "sticky" hookswitch delays answering and initiating calls. Poor contact pressure causes noisy conversation. Check and adjust the springs during routine inspections. NOTE: The springs marked "X" on the wiring diagram (figure 3) should be adjusted to open first and close last to prevent clicks in the receiver when the hooks witch is operated. Replace other telephone components if defective. g. 4.2.4 Telephone maintenance. Telephones receive hard use and should be checked once a year. When possible, replace the regular telephone with a spare telephone, clean the entire unit, and replace defective parts. Replacing telephones for a bench check is good preventive maintenance. a. The dial. Faulty dials cause two complaints: one from the party using it and one from the party wrongly signaled. Dials must operate properly at all times. Although they give no trouble from normal usage, they can become dry and "sticky," reqmrmg cleaning, oiling, and minor adjustments. Dial maintenance procedures are outlined below. Consult technical bulletin 52 7 or standard adjustment sheet 805 for further information. ( 1) Remove the dial from the telephone. Remove the escutcheon ring, finger plate, and number plate. (2) Clean the spring contacts with fastdrying liquid, such as chlorothene. (3) Remove the accumulated lint from the gear teeth. (4) Oil the parts as suggested in technical bulletin 527 or standard adjustment sheet 805, using the oil supplied with installation. A sluggish governor should be disassembled and its bearings oiled. It is not recommended that this be done in the field. If necessary, be sure the governor-bearing screw is adjusted and locked in a position that eliminates excessive end play without bind. (5) Reassemble and test. Adjust the governor to obtain the correct speed of 10 pulses per second. In other words, the dial should restore in approximately one second if the number "O" has been dialed. 8 5. STATION SUBSCRIBER COMPLAINTS 5 .1 Classes of Complaints Classification of station subscriber complaints is the first step in correcting trouble. Complaints can be divided into four groups. 5.1.1 Class 1 complaints. a. Description: Those reported by or affecting only one station. b. Example: Station 6 in figure 6. Cannot receive calls; cannot initiate calls; gets wrong number, etc. c. Analysis: The fault is within that position of the system set aside for the exclusive use of station 6. No portion that is set aside for other stations or commonly used by all stations need be considered. 5 .1.2 Class 2 complaints. a. Description: Those reported by or affecting all stations within a particular area of the organization's plant. b. Example: Stations 7, 8, and 9 of figure 6. Noisy conversations and cannot seize the P-A-X equipment. c. Analysis: The fault is within that portion of the system used by only these three TCI Library www.telephonecollectors.info TO STA.I CA.PR I TO STA.2 TELE NO _ _1_1~STA.I HOUSE CABLE MOF OR TERMINAL BOX STA.10 STA.6 TO STA. 7 CA.PR I TO STA.B STA.9 Figure 6. Sclie111atic diagram u} a key lelejJ/ume s1·s/1·n1. TCI Library www.telephonecollectors.info 9 stations. No portion that is used by other stations or commonly used by all stations need be considered. calls from this point. Since sa tisfac tory results eliminate the building wires as the source of trouble, the telephone itself must be at fault. Correct the fault in the instrument and reconnect the original circuit. 5 .1.3 Class 3 complaints. a. Description: Those affecting all stations reported by and part of the time. b. Example: All 10 stations of figure 6 report that at times the called party cannot be signaled; at times no dial tone is received, at times no busy tone is received. c. Analysis: The fault lies within that portion of the system that is used by all stations. However, since the trouble is not present all of the time, it is probably caused by equipment used only part of the time. Step 3. 5 .1.4 Class 4 complaints. a. Description: affecting all b. Example: All 10 stations of figure 6. No dial tone is received; no station bells can be rung, no busy tone received. Those reported by and stations all of the time. When the above mentioned tests fail, proceed as follows: Disconnect the complaining party's building w1rmg lead at test point 2. Repeat step 1 (above) looking toward the P-A-X from this point. Satisfactory results eliminate this portion of the building wiring lead as the source of trouble. Unsatisfactory results require the repair of this portion of the building lead. Reconnect the original circuit. If necessary, repeat (step 3) above at test point 3 and/or other test points until the defective portion of the building wirmg has been isolated. Repair, test, and reconnect the original circuit. 5 .3 Class 2 Complaints c. Analysis: The fault is within that portion of the system used by all stations; it is caused by equipment used at all times. 5 .2 Class 1 Complaints This type of complaint is caused by trouble that is located within any one of the three dial systems' components. According to section 5.1.1, this could be the complaining party's telephone, his pair of building wiring, or his line relay equipment in the switchboard. Testing procedure: The instrument's terminal block and all building and main terminal boxes are used as test points. Here, the system's components and sections of the ''C'' component may be separated and individually tested. Step 1. Step 2. 10 Separate the complaining party's individual P-A-X equipment (line relay) from his other individual equipment at the main terminal box or test point 1 (see figure 6). Connect a spare telephone and initiate and receive calls from this point. Satisfactory results eliminate this unit as the source of trouble. Reconnect the original circuit, or correct line relay faults. Disconnect the complaining party's telephone at the instrument terminal block or test point 4. Connect a spare telephone and initiate and receive This type of complaint is caused by a defect in that portion of the complete system that is used by the complaining stations only. According to section 5 .1.2, the defect is within that isolated length of home cable serving these stations. Testing procedures: Connections at terminal box D and the main terminal box are used as test points. Here, this piece of equipment may be se pa.rated from the rest of the system's equipment (see figure 6). Step 1. Disconnect one end of this cable from the switchboard at the main terminal box. Disconnect the other end of this cable from the telephones at terminal box D. Step 2. Te st the line wires for grounds, and the pairs for shorts with an ohmmeter. Step 3. Clear grounds and/or shorts in the house cable. 5 .4 Class 3 Complaints This type of complaint is caused by a fault in the equipment that is used by all stations only part of the time. Accordingly, this could be a faulty P-A-X conversation link. Testing procedure: Each conversation link must be given an operating test. Step 1. Connect a spare telephone to the line equipment at the main terminal box. TCI Library www.telephonecollectors.info When available, use spare line equipment as represented by station 11 of figure 6. 5 .1 through 5 .5). Should a line switch need attention, check one of the following: a. Step 2. Step 3. Test the conversation links until the faulty one is located. Its operation under test indicates the cause of the complaint. Proceed as follows: ( 1) Test the station's line switch by placing the plug of the hand test telephone between relay B springs 3-5. "Busy out" the conversationlinkuntil the defect is corrected. 5 .5 Class 4 Complaints (2) If relay A does not operate, check the operating circuit of relay A with the use of the test lamp (see section 6 .3). This type of complaint is caused by a defect in some portion of the complete system that is used by all stations for every call. According to section 5 .1.4, this is the P-A-X common equipment. (3) If relay B does not operate, check the operating circuit of relay B with the use of the test lamp (see section 6 .3). Testing procedure: Common equipment consists of the link distribution and all power and supervisory relays for supplying the tones and ringing current to the conversation links. Step 1. Check for low voltage supply to the P-A-X and for blown fuses. Step 2. Connect a spare telephone to the line equipment at the main terminal box. If possible, reserve the line equipment, such as station 11 of figure 6, for testing purposes. Step 3. Set up calls while observing the operation of various units of the common equipment. Repeat as often as necessary until the faulty portion is located. The station subscriber complains that h