Telex 870-15A User's Manual
Contents
1. OPERATING INSTRUCTIONS MODEL 870 15A AM FM RECEIVER WARNING TO PREVENT FIRE OR SHOCK HAZARD DO NOT EXPOSE THIS RECEIVER TO RAIN OR MOISTURE DESCRIPTION The Raymer Model 870 15A is an all solid state monaural AM FM background music receiver with pro visions for paging The receiver consists of a tuner for the 88 108 MHz FM band the 550 1650 KHz AM band and a 15 Watt RMS audio amplifier with a microphone preamplifier The receiver has a music output and a preamp output jack for connection to an external amplifier as well as a high level phono input jack and a microphone jack which may be switched for either high or low im pedance input The speaker outputs of the receiver are for 4 or 8 ohm or 25 volt or 70 volt balanced lines The Model 870 15A also features an electronic music mute precedence circuit in place of a relay to quickly fade out the music while paging after paging the music is smoothly restored The receiver also has a variable tone control UNPACKING The unit is to be removed carefully from the carton and inspected for any possible damage in transit If there is any evidence of any damage which might have occurred in shipment immediately notify your supplier or the transportation company which delivered it Claims for damage sustained in transit must be made upon the carrier Save all packing material for in spection by the claim agent who will furnish you with the proper forms and will also give y2. OUTPUT CONNECTIONS The speaker s or line matching transformers are connected to the screw terminal board located on the rear panel For short distances any ordinary insulated wire such as parallel lamp cord may be used Long lines have an appreciable resistance with re sultant power loss The use of parallel matching trans formers on either 25 volt or 70 volt lines is recom mended for long distances In all cases it is advisable to run as heavy a wire as possible consistent with the requirements To avoid inducing hum in the system do not parallel speaker cables with any AC line power cables 70 volt distribution systems often require the speaker lines to be run in conduit To determine whether they should be run in conduit check with local city codes for 70 volt system requirements The 4 OHM or 8 OHM output is used when connec ting directly to the speaker voice coils When a speaker with an impedance of 8 ohms is connected to the amplifier use the terminals on the amplifier marked GND and 8 For a 4 ohm speaker or two 8 ohm speakers in parallel use GND and 4 The 25 VOLT or 70 VOLT output is used when con necting to speakers which have line matching trans formers Connecting to the 25 volt or 70 volt tap on the unit permits the use of a number of speakers each with its own corresponding line matching transformer thereby eliminating the necessity of calculating impedances The tap on the line matching transformer is select
3. CIAN OR RETURN THE UNIT TO THE FACTORY MUSIC OUTPUT The Music Output jack may be used to connect to an external smplifier in order to operate a MUSIC ONLY system such as MUSIC ON HOLD simultaneously with the regular Music and Page function of the re ceiver as shown in Figure 2 This output may be phono or tuner as selected by the music switch on the front panel and is not affected by the MUSIC MUTE It may also be used to feed the signal from either phono or tuner to a tape recorder which has a Line in put RAYMER R shielded cable FIGURE 2 MUSIC OUTPUT OF RECEIVER USED TO DRIVE EXTERNAL AMPLIFIER FOR SIMULTANEOUS MUSIC ONLY OPERATION PREAMP OUTPUT The output from the PREAMP IN OUT Jack may be connected to the input of an additional external ampli fier if desired The output from this jack includes both music and page so that both the receiver and the ex ternal amplifier operate simultaneously OPERATION The front panel has five knobs and two slide switches The functions of the knobs are as indicated The Mic Volume control knob adjusts the level of sound for paging or public address and is indepen dent of the Music Volume control knob The Music Volume control knob is used to adjust the level of the sound of the AM and FM portion or phonograph The Tone control knob can be turned to the position that is most pleasing to the listener as it affects both the high and low frequency response The Function k
4. eaker to The Microphone input jack is for an unbalanced line only If it is necessary to use a balanced input an out board matching transformer such as Raymer Model LMT 150 must be used If the signal source is a tele phone line or a 500 ohm input the connection can be made to the amplifier by means of a Raymer Tele phone Matching Adaptor TM 1 or TM 2 The switch above the microphone input selects the proper input impedance The Hi Z position will match either crystal or high impedance dynamic microphones the Lo Z position will match microphones in the 150 to 500 ohm range CAUTION To avoid possible supersonic oscillation which might result in damage to the unit it is mandatory that a shielded metal cover microphone plug be used If it is desirable to fade out the music while paging a dispatcher type of microphone with an auxiliary switch having a pair of normally open contacts should be used The microphone is to be connected as shown in Figure 1 DISPATCHER TYPE MICROPHONE SWITCH CIRCUIT FIGURE I TYPICAL CONNECTION FORA SINGLE MICROPHONE FOR MORE THAN ONE MICROPHONE CONNECT THE SWITCH CIRCUITS IN PARALLEL The PHONO input jack enables the unit to amplify program material from a source other than the self contained radio tuner This input is high impedance with a maximum sensitivity of one half volt and will accommodate the output of a ceramic phono cartridge or the output from any preamplifier
5. ed to give the power desired for each speaker The total of all the power settings should be no greater than the amplifier output rating If the speaker uses a 25 or 70 volt line transformer connect the speaker trans former to the terminals marked GND and 25V or 70V according to the line desired Optimum performance of any transistor amplifier de pends on the proper current delivered at the output terminals Connecting a total load impedance at any tap less than the impedance indicated on the back panel of the amplifier will cause the transistors to deliver more current than they were designed for and will deteriorate the performance of the unit and cause damage to the transistors To prevent this from occurring and to protect the components the unit is equipped with a circuit breaker that will trip if the output impedance is below the specified rated value for example if two 8 ohm speakers are connected in parallel resulting in a 4 ohm impedance and in turn connected to the 8 ohm Output terminal the circuit breaker will trip as soon as the volume control is turned up to the unit s maximum output The circuit breaker located on the rear panel protects the unit from drawing excessive AC line current which could cause damage to the internal components IN THE EVENT THAT THE CIRCUIT BREAKER CONTINUES TO TRIP DO NOT ATTEMPT TO DE FEAT THE FUNCTION OF THE CIRCUIT BREAKER HAVE THE TROUBLE INVESTIGATED BY A QUALI FIED SERVICE TECHNI
6. nob is used to select the AM band the FM band or an external PHONO The Tuning knob is to select the desired AM or FM station The slide switch at the lower left is used for AFC defeat A slide switch at the lower right is to turn the unit on or off The center marking on the dial glass is a LOG scale for easy recording of the position of the pointer for any specific station AFC refers to Automatic Frequency Control and is an electronic means of keeping the receiver properly tuned to an FM broadcast station even when the tuning dial is not precisely set However when tuning to a weak station which is adjacent to a stronger one the AFC function may tend to lock the receiver on the stronger station In such a case the AFC switch should be placed in the OFF position For very precise tuning or selection of a weak station the AFC switch should be placed in the OFF position while tuning When the station is properly tuned the switch may then be returned to the AFC position to lock the receiver to the desired fre quency WARRANTY This unit has been very carefully inspected and is warranted to be free from defects in material and workman ship under normal use and service for a period of one year from date of sale to the original purchaser This Warranty does not extend to any unit which has been subject to abuse misuse neglect accident improper installation or alterations The obligation of Trutone Electronics under this Warranty is limited t
7. o the repair of any defect in ma terial or workmanship and or the replacemnt of any defective part provided the unit is returned to Trutone Elec tronics Inc transportation paid within the year It is recommended that any unit on which service is required be processed through your distributor or installation company wherever possible This Warranty is expressly in lieu of all other Warranties expressed or implied and of all other obligations or liabilities on our part We neither assume nor authorize any other person to assume for us any other liability in con nection with the products manufactured by Trutone Electronics Inc Made in U S A by TRUTONE ELECTRONICS INC 7315 Fulton Avenue North Hollywood California 91605 213 875 0423 3 FM TUNER ASSEMBLY 2 0 FACTORY SEALED kell VOLTAGES MUSIC SHOWA IN our NO SIGNAL PREAMP tox CONDITION IN OUT 2 2K a 70 T D Phono GNO T 2 2N3055 22V 750mf 25y Si 15 We OUTPUT Slss2n 7ov O a2n 2sv 330 NOTES RESISTOR VALUES ARE IN OHMS UNLESS OTHERWISE INDICATED 2LAPACITOR VALUES ARE IN mmf ExCEPT DECIMAL VALUES ARE IN mf OR WHERE INDICATED AS mf 3 B VOLTAGES SHOWN ARE TYPICAL ONLY AND MAY VARY MEASURMENTS TAKEN WITH VT V M INNO SIGNAL CONDITION 3 8 V AM TRUTONE ELECTRONICS INC L 7V FM NO HOLLYWOOD CAL SCHEMATIC 4 2N4003 RAYMER MODEL 570 154
8. ou the necessary instructions for filing a claim INSTALLATION The Raymer Model 870 15A has ample vents for normal ventilation however it should be placed so as to permit free air flow around the unit DO NOT PLACE ANY OBJECT ON TOP OF THE COVER OR IN ANY WAY BLOCK THE AIR FLOW OF THE VENTS DO NOT STORE OR OPERATE THE RECEIVER in areas where the ambient temperature exceeds 140 F The receiver may be mounted in a 5 vertical panel space in a rack using a Raymer RPK 2 rack mounting kit This unit has an AC line cord with a 3 prong plug The line cord should be plugged into a 3 wire grounded 105 to 120 volt 60Hz AC outlet This will also ground the receiver The AC receptacle on the rear panel is a 3 wire grounded outlet which can supply power to accessory or auxiliary equipment Any auxiliary equipment con nected to this AC receptacle is controlled by the POWER on off switch so that turning off the power on the unit turns off all equipment CONNECTIONS All connections are made on the rear panel of the unit INPUT CONNECTIONS All patch cords and input leads other than Music Mute must be shielded cables The Music Mute ieads do not have to be shielded When output leads are run near an unshielded microphone input plug or when run together with the microphone precedence leads a supersonic oscillation may occur When this does occur it will appear as a distortion in the amplifier output and oftentimes will cause the circuit br
9. such as tape phono etc If the source into the PHONO input is from leased telephone lines a Raymer TM 2 telephone adaptor is required to match the telephone lines to the input PREAMP INPUT If it is desirable to add a signaling annunciator or alarm to the Music and Page system a RAYMER MODEL TGSP 3 Tone Generator may be connected to the receiver The output of the TGSP 3 should be con nected to the PREAMP IN OUT jack By connecting in this fashion the tone or alarm is unaffected by any of the front panel controls ANTENNA INPUTS Separate antenna inputs are made available for the AM and FM portion of the tuner by means of a terminal board For normal FM reception the short antenna lead supplied with the unit is sufficient for most locations In the event that the tuner is located in a remote area an external Dipole antenna will increase the number of distant stations that can be received This external antenna is to be connected across the terminals marked FM ANT For AM reception the receiver has a built in Hi Q Ferrite loopstick antenna which is all that is normally required for local AM reception To increase the recep tion of weak AM stations in the fringe area it may be advisable to rotate the loopstick to obtain the loudest signal In instances where the tuner is used inside of an all metal building or in a weak reception area an outside antenna is required Connect an external antenna lead to the terminal marked AM ANT
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