Loudspeaker Matching
ÇucceJrfuL.SLkVI(U N41AM PL.OUTPUTFig. 1. When three 8 -ohm loudspeakers are connected inAPRIL, 1951series, the total impedance will match that of a 24 -ohm tap.LOUDSPEAKER MATCHINGby JOHN F. RIDEREditor's Note: This article on Loud-speaker Matching is an excerpt fromChapter 3, entitled "Impedance Matchof INSTALLATION ANDSERVICING OF LOW POWERing,"PUBLIC ADDRESS SYSTEMS byJohn F. Rider, published by John F.Rider Publisher, Inc. The May issueof SUCCESSFUL SERVICING will containanother article on the subject of impedance matching.The matching of one component to anotherin a p -a system is very important. A badmatch between a good amplifier and a loud-speaker will give poor results in terms ofpower output and fidelity.oAM PL.OUTPUTán (rnspeakers are directly connectedimpedances. Thus, if three 8 -ohm loudspeakerscombinations, the impedance offered by thetotal load may be anywhere from 0.1 ohm toare series -connected, matching is secured byconnecting the entire load across a 24 -ohm tapon the output transformer as shown in Fig. 1.in varioustypes of series, parallel, or series -parallel500 ohms in commercial practice.Generally when the distance between theamplifier output transformer and the loudspeaker is about 200 feet or less, the line canbe run at the impedance of the voice coil.The term "line impedance" as used here doesnot refer tó any characteristic which the lineitself has but means that the conductors areconnected to a load of that type impedance.Thus a low -impedance line means that thewires are connected to a low -impedance load.Any combination of loudspeakers can be connected by a low -impedance line.8{L211Fig. 2. Four 8 ohm loudspeakers connected in parallel will match the impedance of a 2 -ohm. tap.impedance of the plate circuit. For the bestpossible fidelity, the source and load impedances should match within about 10 percent.The impedance of a loudspeaker is the impedance of the voice coil and is always included in loudspeaker specifications. This impedance, which is equal to the voltage acrossthe moving coil divided by the current throughit, is given at a particular frequency, usually400 cycles. Voice -coil impedances generallyrange from 2 to 16 ohms, with most between6 and 8 ohms, however, in special loudspeakersit may be as much as 50 ohms. When loud -Matching of Loudspeakers onLow -Impedance LinesThe total load impedance offered by twoor more loudspeakers connected in seriesAM PL.OUTPUTwhen all have the same voice -coil impedance,is equal to the impedance of any one loudspeaker divided by the number of loudspeakers.Thus, if four 8 -ohm loudspeakers are connected in parallel, the total load impedanceZr 8/4 2 ohms. For proper matching, theloudspeakers should be parallel -connected toa 2 -ohm tap on the output transformer asshown in Fig. 2.The total load offered by four or moreloudspeakers connected in series -parallel,when all have the same voice -coil impedance,is equal to the impedance of any series branchline, divided by the number of such seriesání Given an output tube having a stated platecircuit impedance, it is necessary that theloudspeaker voice -coil impedance match theThe total load impedance offered by twoor more loudspeakers connected in parallel,oo8c1islines that are in parallel. If four 8 -ohm loudspeakers are series -parallel connected so thatthere are two loudspeakers connected in seriesin each branch and two branches in parallel,then the effective load is 16/2 8 ohms. Thisload should be connected to an 8 -ohm tap forproper matching, as shown in Fig. 3.Matching on High -Impedance LinesWhere several l,nrdspeakers are situatedat some distance from the amplifier and from,TnC8n rItin11-.811-f-1Fig. 3. When four 8 -ohm loudspeakers are connected in two parallel branches of two series connected loudspeakers each, the total load impedance will be 8 ohms.the sum of their individual impedances. Thistotal load can match the amplifier output byconnecting it across the same value of tapeach other, then each loudspeaker (or groupof loudspeakers) can be matched to a 500 -ohm(Continued on page 10)
Successful Servicing, April, 19512elev.Mien etaCrosley 10-401, 10-414MU, 10-416MUSarkes Tarzian TT3The following revisions have been made inthe TT3: The 6AG5 has been changed to a6CB6 with no change in the wiring; a 680-µµfcapacitor has been added from ground to thejunction of R1 and the agc lead.Motorola 9L1Model 9L1 incorporates a Chassis TS -18 orTS -18A and is electrically identical to thechassis published. The only difference is inthe size of the picture tube and the hardwareused with 9L1.It has been found that on some receiversthe horizontal oscillator exhibits a tendencyto drift causing the receiver to fall out ofhorizontal sync after operating several hours,or, if the horizontal sync adjustment was madeafter the receiver has been operating for sometime, the picture will not fall in sync when theAR-16CD-3CR, AR-163CR, AR -216,AR -316, AR-316-3CM, AR-816-3CMThese models are similar to Models AR16CX and AR-816-3CR, and employ 16 -inchround picture tubes.Sets below Serial No. 22,000 did not containa high -voltage filter capacitor as the coatingon the outside of the picture tube had a capacitance effect and the capacitor was not neces-Since picture tubes now leaving thefactory do not have an aquadag coating uponthe outer surface of the tube, it will be necessary to add the high -voltage filter capacitorPart No. CC -0070, 500 µµf 20,000 volts d.c.(as shown in the schematic for Model M169),tuting it with a unit that is known to be ingood alignment.SWITCHuted to the 0.01-4 capacitor, C160. Thiscapacitor, if it is of the molded type (TypeAGCTERMINAL AT C10610KPOTENTIOMETER487), may change capacitance with temperature change sufficiently to cause the receiverto fall out of horizontal sync. To make correction, replace the 0.01-µf molded capacitortor (Part No. 39001-13).If trouble is experienced with the abovemodels in centering the picture and reducingthe neck shadow, it may be caused by reversed polarity of the focus coil. If this is(PART NO.39368-2)4V. SUPPLYTERMINAL AT C171Battery pack arrangement used as biasfor age circuit.In some cases, when using test equipmentto align the above models, or when the gainof the receiver may be affected by anothering, when the focus coil polarity is incorrect,section of the receiver such as improper functioning of the horizontal deflection circuits,it is advisable to substitute a bias for the agccircuit which can be adjusted manually to anydesired setting. It is suggested that the battery pack arrangement shown in the accompanying diágram be used for this purpose byclipping the two external leads into the chassis wiring at the points indicated. No wiringchanges are necessary. A spst switch is employed to break the circuit when the batterylies in the fact that the magnetic field fromthe focus coil interacts unfavorably with theprevent a run down battery, due to the switchsuspected, the polarity can be changed by re-versing the current through the coil. To doMuntz M159Picture and sound separation can be causedby a narrow bandpass of the i -f stages, narrow bandpass of the r -f tuner, or a combination of both. Check the i -f bandpass with asweep generator, marker, and scope. Theresponse curve should appear as shown forModel 10-401. Check the r -f tuner by substi-receiver is cold. This trouble may be attrib-C160 with a 0.01-µf, 600-v, paper -type capaci-Affiliated Retailers AR-16CD,sary.duce a "North Pole" on that face of the coilnearest to the tube socket.this, interchange the leads to the focus coil atthe points where they are soldered under thechassis. Try centering the picture again. Ifthe centering action is easier and the neckshadow diminished, and if the angle the focuscoil makes with the neck of the picture tubeis almost a right angle, the connection iscorrect. The reason for difficulty in center-if a new picture tube is installed in chassisfield from the ion trap. When the coilbelow 22,000.connected correctly, the current flow will pro -ispack arrangement is not in use. In order tobeing left turned on, it is suggested that amicro -switch be incorporated in one side ofthe unit. When the unit is placed on thechassis with the switch down the switch con-tact will close. When the unit is removedVACUUM -TUBE VOLTMETERS( Revised and Enlarged)by John F. RiderThe 1951 revision brings the text up to date in its coverage of all types ofvoltmeters -diode, triode, rectifier -amplifier, tuned, amplifier -rectifier, and slide back. This is the only book that deals exclusively with vacuum -tube voltmeters.The theory and application of the various types are described and presented incompleted form -including schematics, parts lists, and maintenance instructions.Examine the Table of Contents. Everything for every VTVM use! Student,service technician, engineer, laboratory, instructor -all can use it to goodadvantage.TABLE OF CONTENTS1 -Fundamentals of Vacuum -Tube Voltmeters; 2 -Diode Vacuum -Tube Voltmeters; 3 -Triode Vacuum -Tube Voltmeters; 4 -Rectifier -Amplifier Vacuum Tube Voltmeters; 5 -Tuned Vacuum -Tube Voltmeters; 6 -Amplifier -RectifierVacuum -Tube Voltmeters; 7 -Slide -Back Vacuum -Tube Voltmeters; 8 -Vacuum -Tube Voltmeters for D -C Voltage, Current, and Resistance Measurements;9 -Probes for DC and RF; 10 -Design and Construction of Vacuum -Tube Voltmeters; 1 1 -Calibration and Testing of Vacuum -Tube Voltmeters; 1 2 -Applications of Vacuum -Tube Voltmeters; 13 -Commercial Vacuum -Tube Voltmeters;14 -Maintenance of Vacuum -Tube Voltmeters; Bibliography; Index.Published April, 1951213 illustrations400 pages51/2" x 81/2" 4.50John F. Rider Publisher, Inc.480 Canal StreetNew York 13, N. Y.from the chassis the .switch will open automatically.Westinghouse H -605T12, Ch.V-2150-101In some deflection yokes used in this model,the nut for the deflection yoke adjustmentwing -screw may bind with the metal channelin which it rides. The binding makes it difficult to position the yoke snugly against thebell of the cathode-ray tube. If the yoke isnot fitted snugly against the bell, shadows mayappear around the edge of the crt face. Tocorrect this condition, loosen the deflectionyoke adjustment wing -screw and carefullyforce the deflection yoke forward as required.In extreme cases, it may be necessary to remove the deflection yoke and pry the nut toward the rear of the yoke using a screwdriver.ORDER YOUR COPY NOWRIDER TV VOLUME 6Tele King MST14, 14TR, 17CA, 17R0,114A, 117, 117C, 117CA, 117L0, 162.173, 516AThese models are similar to Models 116 and516. Models MST14, 14TR, and 114A employ14 -inch picture tubes. Models 162 and 516Aemploy 16 -inch rectangular picture tubes.Models 17CA, 17RO, 117, 117C, 117CA,117LO, and 173 employ 17 -inch rectangularpicture tubes.
3cssJnl .1 crviciug, 1 pr il, 1951These 5 "Precision" Instruments* Build Your Service Sales Future on a FirmProvide a Complete, ModernService Lab. for TV -FM -AMFoundation With.at only moderate cost.NC2 OF A SERIES OF MATCHED COMBINATIONSSERIES 10-12 (P.M.)SERIES E-400 (P.M.)SERIES E-2000 (P.M.)SERVES ES 500SERIES E -200C (P.M.)SERIES E-400 (P.M.)SERIES ES -500SERIES EV-20SIGNAL AND MARKERSWEEP SIGNAL5" OSCILLOSCOPETrue Zero Center VTVMSERIES 10-12 (P.M.)Electronnrric *GENERATORGENERATORWide Range& Multi -range Test SetNarrow and Wide BandHigh SensitivityTUBE MASTERExceptional Accuracy andStability Direct reading48 ranges to 1200 V., 2000megs., 63 DB, 12 amps.Employs famous "PRECI-88 KC to 120 MC. 1000 pt.vernier calibrating scale0-100% Modulation A.V.C.A.G.C. Substitution networkComplete with outputcable and technical manual.In standard panel 19x 121/4".Net Price: 71.2bSweep for F.M. and TVDirect Freq.reading2to480 MC. Multiple CrystalMarker 8 tubes includingV.R. and rectifier RG/62UCoaxial Terminated OutputComplete with : crystalsIn standard panel 19 121/4".Net Price:' 140.00V. Amp. Response to 1 MC.Low C, High R input StepAttenuatorZ axis modu-9 tubesVoltage Regulated BridgeType Circuit 131/4 Megs. D.C.Input resistanceDirectComplete with light shieldHeavy gaugeand maskOptional RF-10-A High Freq.Probe Heavy gauge steellation terminalsincl. V.R. and 2 rectifierssteel case. 81/4 x 141/z x 18".Net Price: 159.50SION"reading high freq. scalescase61/4x5xElectionamictubeperformance testing circuitlnt/º"Net Price: 68.25plus dynamic Battery Tester12 element, anti -obsolescent -free -point lever systemRoller -chart Cusil short checkNoise testsInstandard panel 19" it 171/2".Net Prise: 106.50SERIES TV -3 SUPER HIGH VOLTAGE SAFETY TEST PROBE. Extends range of Series EV-20 to 30 KVdirect reading. Series TV probes available to match most VTVM's and 20,000 ohms per volt test sets.(NOTE: For deluxe Series EV 10 VTVM, with extra -large 7" meter, order Series TV -1 probe.) Net Price: 14.75BUY PERFORMANCE-NOT SPECIFICATIONS!-BUY "PRECISION""PRECISION" PERFORMANCE, ACCURACY. WORP,MANSHIP and VALUEhave been setting a standard of comparison for over 15 years.DO NOT BE MISLED.It is not "PRECISION" test equipment unless itis manufactured by Precision Apparatus Co., Inc., Elmhurst, L.I., N.Y.-'Precision" Instruments areor display at Trading radioequipment distributors.TV FM AM'Reg. U.S. 'at. Off.OTHER MATCHED COMBINATIONSThe instruments shown above illustrate one of many possibleMATCHED COMBINATIONS of diversified "PRECIISIOIN" TestEquipment for TV -FM -AM. Each combination provides a selectedand basic, modern, efficient Laboratory at moderate cost.PRECISION APPARATUS CO., INC.92-27 Horace Harding Boulevard, Elmhurst 14, New YorkExport Division: 458 Broadway, New York, U.S.A.Cables-MorhanexIn Canada: Atlas Radio Corp., Ltd., Toronto, OntarioPlease mention Successful Servicing when answering advertising.ConvenienrPurchaseTerms'can be c -ranged with yourfavorite Precision Distributor.AM FM TV .
Successful Servicing, April, 19514New Round Shaft Mallory Midgetrol*Saves Valuable Installation TimeSingle SectionMallory MidgetrolNow the time proved Mallory Midgetroloffers two important new time -savingwith every Mallory Midgetrol. It givesyou utmost convenience-without sacri-features.ficing a stable, permanently secured shaft.This sturdy 1%s" control is supplied withAlso, switch attachment is made simplea permanently fixed, tubular brass shaft thatand sure by positive indexing. Switchcan be adapted for split -knurl or flattedtype knobs in a few seconds by insertingone of the two steel shaft -ends packagedlocks securely in position withoutremoving the control housing.Dual ConcentricMallory MidgetrolThis revolutionary new control can beassembled in five easy steps, in less thansupplied. Extremely simple instructionsshow you how to assemble them quicklyfive minutes-permits you to match aand surely-without soldering-withwide range of combinations immediatelyfrom convenient distributor stocks, andwithout high "time" costs.only the simplest of tools.The "exploded" view below illustratesthe parts and assembled control sectionsBoth front and rear sections are factoryassembled and carefully inspected. You canbe sure that your final dual assembly willgive the performance you want!Make Sure !Make it Mallory !P R. MALLORY 8 CO Inc.MALLORYThe Mallory Midgetrol givesyou fast, sure, simple installation-with precision -controlledcarbon element, smooth taper,quiet operation, accurate resis-tance value and less drift inTV sets.*Trade MarkCAPACITORS CONTROLS VIBRATORS SWITCHESRECTIFIERSVIBRAPACK* POWER SUPPLIESRESISTORSFILTERS'Reg. U. S. Pat. Off.APPROVED PRECISION PRODUCTSP. R. MALLORY & CO., Inc., INDIANAPOLIS 6, INDIANAPlease mention Successful Servicing when :umuVering advertising.
5Successful Servicing, April,seriously recommend that if time does notpermit a complete reading of each circuitchange, the change should be glanced at priorto filing. The trouble being eliminated will beremembered even though the exact proceduremay not always be retained in the mind. Quitea few of these troubles are obscure and, whiletied specifically to one receiver in the refer-Juererr/aLSERVICINGREG. U.S. PAT. OFF.Vol. 12No. 6APRIL, 1951Dedicated to the financial and technical advancement of theElectronic Maintenance Personnelence, may be duplicated in some other receiver.The remedy as given may not be applied "inti to," but at least some direction of approachkill he indicated.Published byJOHN F. RIDER PUBLISHER, INC.480 Canal StreetNew York 13, N. Y.WOrth 4-8340WOrth 4-8341JOHN F. RIDER, EditorE. H. BEAUMONT, Associate EditorCopyright 1951 by John F. RiderNo portion of this publication may be reproducedwithout the written permission of the publisher.industry ! It is a certainty that it will becomeeven more important as the days and monthspass. One of the gripes that is being voicedby many service technicians is the time required to untwine leads wound around a con-necting point as a part of the unsolderingoperation. The loss of time, however, is notthe only source of aggravation. An equallyimportant sore spot is the frequent need forchanging the lead dress of adjacent wires andcircuit components in order to unwind theconnection. Sometimes this is voluntary and,quite frequently, involuntary.Considering the importance of correct leaddress in TV receivers, and for that matter inr -f, oscillator, and i -f systems of all receivers,it is only natural that the service technicianbe anxious to keep all unnecessary changes inwiring and component location to a minimum.To be forced to deliberately alter componentconditions and then be certain that they arereturned to their original locations so thatresonance conditions and feedback conditionsbe normal, is a problem. Of that thereisno doubt. We have had the experience ourselves.Admittedly, a simple expedient when aconnection is to be interchanged or a defectivepart is to he removed, is to clip a connectingwire at the junction point or soldering lug.This is quick, but it is messy and, strangelyenough, is viewed with disfavor by meticulousservice technicians. Isn't it possible to adapta standard procedure of hooking the wirethrough a hole in the soldering lug or aroundthe connecting point and then soldering? Thiswould make the unsoldering operation verymuch simpler than having to untwist severalturns. Quite frequently the solder cools andSER-Manuals and published in SUCCESSFULVICING make direct reference to servicingproblems being solved by the circuit change.PHIL!RIpEERTURNED OUT ALL THOSEYEAH? YOU DON'TWORK FASTERMAN UAL7SPPPdigIhappens in the TV receivers which are soldto the public. It is wrong for the servicemanto feel that he does not have time to readcircuit descriptions. He must find time. Theservicing industry is not a static industry.It is continually on the move, and the technicalbackground of every TV technician must expand with it.JOHN F. RIDERSarkes Tarzian TT2The following revisions have been made inthe TT2: L213 is now .180 (was .173) ; L313is now .155 (was .160) ; and L401 is now .165(was .170).Tele Xing 16CO3CR, 16CX, 162, 216,316, 416CAF, 916, 916C, 916CAF,This is very important information, and weTHAN ME -HOWDID YOU DO IT?YOU'RE RIGHTvicing industry is concerned, the circuitdescriptions which are contained in RiderManuals, especially the TV Manuals, are vitalsources of technical information. They comprise an education because they explain whatQuite a few of the changes relating to radioand television receivers contained in RiderJOE-ACOUPLE OF DAYSWITH REPAIRJOBS!knowledge may be piled. As far as the ser-ChangesJOBS IN RECORD TI ME!AGO YOU WERE LOADEDlay the foundation upon which more and morethe manufacturing stage, it makes for anequally good connection and a perfectly safemechanical joint. Above all, it will be a boonto the servicing industry.IYOU AT THE GAM E TON IGHTfor, after all, it is the practice of all peoplewho have had a formal education and mustkeep up to date with the changing technology.A formal education can do nothing more thanhardens before the untwisting job is completed,and it becomes necessary to re -heat the junction. If the soldering is done properly duringRIDER MANUALS HELP BREAK RECORDS!I N EVER EXPECTED TO FIND\!any of the practicing servicemen of America are self-made men. By this we mean thattheir technical background has been gained byexposure to literature, by continued readingof theory, and, finally, by daily work at thebench. Expanding the storehouse of knowledgein this manner is nothing to be ashamed ofCURTAIN TIMETime is of the essence in the servicingThe Self -Made Man3163CMThese models are similar to Models 416 and716 and employ 16 -inch round picture tubes.THERE'S NO SECRET TO IT -I USEYOU'LL N EVER REGRET IT -THEY'RERIDER MANUALS AND WORKEAS/ER AND FASTER ANDTHE BEST BUY I EVER MADE -I'MSTILL USING A VOLUME I BOUGHTHAVE MORE TIME TO MYSELF -YOU CAN DOTHE SAME THING20YFARS AGO- REMEMBER TOBUY VOW M E 21 ANDTV6 THEY'RE THE LATEST!IF THAT'S THE ANSWEI M GETtING A SET I WORK SO HARDIMAT THE GAMETONIGHT TORELAX!vo maNUAL IANJ.UIUIINu,,,,,Ri7r
6Successful Servicing, April, 1951e%uidia, t eltaii9edRCA 8T241 SeriesCheck to see that the receiver antennaDeWald DT -160The focus coil has been deleted from thecircuit. This information was omitted inadvertently from the change notice on thismodel that appeared in the February 1950transformer T115 is connected properly andthat no windings are open. Remove 8T241r -f unit and change R11 to 10,000 ohms.issue of SUCCESSFUL SERVICING.Affiliated Retailers AR-MST14,AR-MST16, AR-16ATR, AR -114AModels AR-MST14 and AR -114A aresimilar to Model AR-14TR and employ 14 inch picture tubes. Models AR-MST16 andAR-16ATR are similar to Model AR-16TRand employ 16 -inch rectangular picture tubes.If the receiver is to work in weak signalareas and never to receive a strong signal,then maximum r -f gain can be obtained byinstalling a small bleeder just to supply -0.5volts for the r -f amplifier grid. R12 shouldbe disconnected from its present position andreconnected to this -0.5 -volt point. Checkoscillator injection into mixer. This shouldread at least -2.5 volts on all channels whenmeasured by a VoltOhmyst at test connectionR13. If this is not achieved, adjust the linkbetween L2 and L3 until such injectionobtained.isRealign r -f unit for peak performance onthe channels to be received.Change R102 to 68 ohms. Realign the pic-ture i -f making sure that the high frequencyslope of the response curve is broad as specified in the service data. If receiver is to beoperated in a very weak signal area, placethe picture carrier at 60%, or even 80% onthe slope. Check to see that the receiverretains proper response at low signal inputlevels, and -1.0 -volt i -f bias. Some changein response is normal, but the picture carriershould remain high on the curve. This align-ment causes the picture to be smeared onstrong signals but produces the best pictureson signals of less than 100 microvolts.Make sure that the a -c line feeding thereceiver is at least 115 volts at all times, asthis radically effects the kinescope anode volt-Quality is built-in not "tested -in." Nevertheless, the guarantee of built-in quality isunlimited testing. Here is one of TUNG-SOUSnumerous and exacting quality control tests-the chemicals used in the screen of theTUNG-SOL picture tube are analyzed in thespectrograph to determine purity.age. If the horizontal deflection system isoperating improperly or is incorrectly adjusted, there may be insufficient high voltageon the kinescope. When a "snow flake" occurs, this causes the tube to bloom, makingthe snow more pronounced. Make sure thatall B voltages are normal, especially the6BG6 screen. Change R181 to 150,000 ohms.Adjust the drive trimmer as far counterclockwise as possible. It should be possibleto have at least 9000 volts on the kinescopeat this point.Adjust the focus coil carefully so as to obtain best focus in white areas of the picture.Modify the video amplifier to saturate onwhites, thus reducing the prominence of the"snow." Disconnect R124 from -120 voltbus and return it to ground. This causes ad-justment of the picture controlto affectbrightness, however, once set, these adjustments can be left alone.Adjust the agc threshold control counterclockwise from the normal position to provide the best signal to noise (snow) condition.Unfortunately, this makes the sync more susceptible to impulse type interference such asignition, etc.Cut the antenna transmission line lengthto provide maximum signal. This effect ismost noticeable on the high channels.In general, use the highest gain antennaarray that can be had, place it as high ill theair as possible and above all surroundingENGINEERED to keep pace with the growth of the electronicindustry.MANUFACTURED to quality standards which meet fully the performance requirements of every leading radio and television setmanufacturer.obstacles, especially power lines. In somecases, however, if the electric field is distorted, a simple antenna may produce moresignal than an elaborate array, and the heightmay become critical. In selecting an antennafor gain, make sure that high gain occurs onthe channel or channels to be received. Someantennas, in order to reduce size, cut off badlyon channel 2, and on some, the response isslightly down even on channel 3. In general.the best antenna or array for any particularchannel is one cut for that channel.Unless bothered with an extremely highnoise level (ignition, etc.) the antenna transmission line should be the 300 -ohm open type./TUNG.SOLRADIO, TV TUBES, DIAL LAMPSaTUNG-SOL LAMP WORKS INC., Newark 4, N. J.ChicagoDallasDenverDetroitSales Offices: AtlantaNewarkLos AngelesPlease mention Successful Servicing when answering advertising.Coaxial and twinex have higher losses thanthe open line, which in weak signal areascannot be tolerated. In time, however, openwire line may foul up and have to be replaced. This fouling shows up as a loss ofsignal in wet weather.The above modifications make these receivers so "hot," that a booster is not likelyto be of help in the receiving of weak signals.Tele Bing MST12, 312These models are similar to Model 812 andemploy 121/2 -inch picture tubes.
7Successful Servicing, April, 1951MIDWOODRADIO AND TELEVISION SERVICESERVICEMEN ARE1328 Coney Island AvenueBrooklyn 30, N. Y.You need it!John F. Rider Publisher, Inc.480 Canal StreetNew York 13, N. Y.SOLDGentlemen:haveuse Rider TV Manuals in my service work.found the information covered more exact, andyou can rely on the schematics because they are directfrom the manufacturer. can be sure that workinghave the complete servicingwith Rider's Manualsinformation to do an accurate and rapid job.Keep up the swell work you are doing for theIIYes, SOLD on RIDER MANUALS! And for good reason,Get it.Now!Itoo! Check for yourself .RIDER MANUALS give youIALL the information you need! COMPLETE coverage ofthe manufacturers' ENTIRE receiver output! ALL pro-duction runs (not just pilot models) . with ALL ofthe changes!Yes, and ALL of the data is ACCURATE, AUTHENTIC,FACTORY -AUTHORIZED! ALL of it comes direct from theservice departments of the receiver manufacturersNew Rider TV Manual.VOLUME 6servicing industry.at your nearby Jobbers'today! Hurry in for yourSincerely,Herman Davisthemselves, and is compiled by RIDER into these indispensable television servicing manuals., giving you,informationin this ONE course, ALL of the pricelesscopy before the presentsupply is exhausted!that you MUST have. and you can see WHYFor In the FIRST FIVE RIDEREXCLUSIVE FEATURESRADIO REPAIR & SALESTVMANUALS, containing 10,544 pages:273 Central AvenueNewark 4, N. J.731 pages are devoted to understandable descriptions of circuit action . telling you HOW the circuitfunctions. NOBODY, but RIDER furnishes you with somuch of this necessary information!293 pages are on signal waveforms . so vital toi.f.,any rapid trouble diagnosis in picture i.f., soundvideo, sync and sweep circuits. Nobody, but RIDER,offers anywhere near this amount of important data!337 pages have factory -issued unpacking and installation instructions. Nobody, but RIDER, brings youas many of these helpful, time -saving notes!John F. Rider Publisher, Inc.480 Canal StreetNew York, N. Y.Gentlemen:We have been in business for 18 years and havealways used Rider Manuals. We have found them tobe invaluable in our work. can truthfully say thatwe couldn't possibly have gotten along without them.We have also found the information contained inRider's Manuals clear and complete. We look forwardto each new manual when it comes out.IONLY INRIDERBest wishes for your continued success.Frank A. Morrocco*****.Television Manual Volume 6 (Plus Index) -- . 524.00Television Manual Volume 5 (Plus Index l. . 24.00Television Manual Volume 4 I Plus "Ilo,c ItWorks" Buck and Index). . .Television"ILnc. . .Volume 2-In lira,Manual24.00It24.00.largerpage size. 12" x t:,". II'lus "lion It Works .!look and Index) . .Television Manual Volume I (Plus "flow ItWorks- 'took and Index).Volume XXIVolume X. .Volume XIXVolume X V I I.IVolume XVIIVolume XVIVolume XV . . . .Volume XIV to VII. . . . .24.0019.80. . . . . . . . . . .(each volume) . . .Volume VIAbridged Manuals I to V lone volume).Master Index. Covering Manuals Vol. I to NV.PA Equipment Manual. Volume 01.5018.00John F. Rider Publisher, Inc.480 Canal StreetTOWN RADIO & TELEVISION CO.72-06 Main StreetFlushing, New YorkMake sure that your Working Library of RIDERwith ALL of theseMANUALS is completeindispensable volumes on hand.I PlusCircuit Changes.RIDER TV MANUAL-Vol. 6ACCURATE . AUTHENTIC . . FACTORY AUTHORIZED TV servicing information directfrom 66 manufacturers. BIG 12"x 15" pageLarge, easy -to -read diagrams. Equivalent of,Work.- (took :utd Index) .Manual Volume 3Shooting.COMPLETE Alignment Data.COMPLETE Parts List.size, and al
loudspeaker voice -coil impedance match the impedance of the plate circuit. For the best possible fidelity, the source and load imped-ances should match within about 10 percent. The impedance of a loudspeaker is the im-pedance of the voice coil and is always in-cluded in loudspeaker specifications. This im-pedance, which is equal to the voltage .
Quad ESL-63 US Monitor loudspeaker (LG) 104 Angstrom Reflexion loudspeaker (JA) 111 Avalon Audio Black Bag loudspeaker (JA) 114 Rogers LS3/5a loudspeaker (JA) 115 Taddeo Loudspeaker Company Domestic Monitor One loudspeaker (JA) 119 Wharfedale Diamond Ill loudspeaker (JA) 122 FOLLOW-UP Marantz CD-94 CD player (JA) 95
the loudspeaker in single-wire mode. This allows you to connect the loudspeaker conventionally using one pair of cables. Standard Connections Connect the RED ( ) terminal of the RIGHT loudspeaker to the RED, Positive ( ) terminal on the RIGHT channel of the amplifier. Connect the BLACK (-) terminal of the loudspeaker to the matching BLACK,
or covered area. The loudspeaker amplifiers have protection circuits that temporarily shut the loudspeaker off when extremely high temperatures are reached. This can happen on hot days when the loudspeaker is in direct sunlight. Do not use Live X loudspeakers in an environment where temperatures exceed 40 C (104 F).
roll over the carton so that the loudspeaker and all stratocell caps remain in the carton. 3. Lift away the cardboard carton leaving the loudspeaker cradled in the stratocell caps. 4. Remove the upper half of the end caps and lift the loudspeaker away from the packaging. 5. Remove the felt bag and position the loudspeaker in the listening room.
a shaded or covered area. The loudspeaker amplifiers have protection circuits that temporarily shut the loudspeaker off when extremely high temperatures are reached. This can happen on hot days when the loudspeaker is in direct sunlight. Do not use ZxA1 loudspeakers in an environment where temperatures exceed 40 C (104 F).
rating of the Loudspeaker (usually measured at a midrange frequency) might not always agree with the impedance of the Loudspeaker at low frequencies where the greatest amount of power is required. Contact the Loudspeaker Manufac-turer for additional information about the actual impedance of the Loudspeaker before connecting it to the McIntosh .
to always match the impedance of the Loudspeaker to the Wadia a340 Power Amplifier Connections (4 or 8 ohms). Refer to "How to Connect" pages 8 thru 11. Note: The impedance of a Loudspeaker actually var-ies as the Loudspeaker reproduces different frequencies. As a result, the nominal impedance rating of the Loudspeaker (usually measured at
others are just rough paths. Details are given in a document called the Hazard Directory. 1.3 Signals Most running lines have signals to control the trains. Generally, signals are operated from a signal box and have an identifying number displayed on them. Signals are usually attached to posts alongside the track but can also be found on overhead gantries or on the ground. Modern signals tend .
