Nutone IM-303 Intercom

SERVICE MANUAL NUTONE MODEL IM-303 3-WIRE Built-in Centralized Radio/Intercom System | | 7 3 pd oH Lord 1 Nulone Housing Products MADISON & RED BANK ROADS © CINCINNATI, OHIO 45227 e PHONE 1-513-527-5415 Part No. 46646000 Printed in U.S.A. 11/74 CONTENTS PAGE A DE 3 INSTALLATION BLOCK WIRING DIAGRAM . LL. RR a a a 4 a a RR RG 3 OPERATIONAL CHECKOUT Master Unit... eh rte eee ee ee ee eae 4 AU MP вннннн невинно вов в ово вввововввовьвва нова ваввввввввевь. 5 Intercom Operation .... 1222002 444 4 4 0 4 4 4 4 4 4 4 4 A 4 A A 4 A4 4 4 8 4 8 8 8 4 4 0 4 4 4 a 8 a 4 1 1 1 A LL 40 5 15-37 Inside 5 In. Speaker/Clock Timer 1... 122120 00 4 4 4 4 4 ee 4 a a 4 4 ae a 4 a ee a aa a 0 6 Backç:ound Music ......2220 21211 1 4 2 0 2 1 A 4 4 4 a 8 4 4 4 8 4 4 4 4 4 0 8 8 0 8 0 0 0 0 a ee eee eee 7 THEORY OF OPERATION Power SUpply .......ece.eooederecoraaaranoona dnd erdrmocoeoodoereondrao o 0 ea 8 a Me 0 aa 0 +0 7 Radio Module ......22 0020044 4 4 4 2 44 4 4 4 RR RK RR RR RER 0 8 eee eee 8 Audio Controls: Imputs and Outputs .... 1.224444 0 64 4 4 4 4 4 4 4 4 0 4 4 4 4 4 4 4 4 8 0 0 8 a 4 4 8 0 0 0 9 AM/FM ALIGNMENT CHART ........00 011444 0 0 a a RR RR a a a au ee a a a 0 a a au 6 10/11 Audio Amplifier ........o e 8 44 44 4 4 8 0 0 0 8 8 RR 8 8 4 8 4 4 4 4 8 8 4 4 4 8 4 4 4 8 4 4 4 0 a 4 a 1 a a 00 0 12 Control Module & Intercom Switching ... 1.122200 02 444 4 4 4 4 4 tit it 0 4 a 8 0 8 4 0 0 a 0 a a 4 2 40 12 Terminal Board ......202200 2041144 14 4 4 4 4 4 6 4 0 RK KR RR PA 14 SERVICING THE IM-303 SYSTEM General .......oé_emmeroreondrrendooaroredenoaermaneacoarerorarenaavnrane cerezo 15 Removing Master Unit From Its Wall Mounting .. . 1.222240 2 04 4 8 4 0 4 4 1 0 a 4 0 8 4 a 8 a 0 0 0 4 a 1 2 1 0 0 16 FIELD REPLACEABLE PC MODULES ...........042 0000 nan 000 eu ue 1 00 a 0 1 a un» Centerfold 17/18 AMPLIFIER/POWER SUPPLY PC BOARD .........2.000 00000001 0 0 0 0 0 0 a 0 0 0e 0100 0 Centerfoid 19 VOLTAGE CHART .......2.2.448 0500005000 01 01 0 0 1 00 0 00 00 1 08 0 0 0 0 00» » 0 « + < « » « Centerfold 20 SCHEMATIC DIAGRAM .....oÑ..eode-—aaorrvvranoranannoareaanvoaaarecarorooo Centerfold 21/22 IM-303 SYSTEM INTERCOM SWITCHING & CONTROL ............. ccna... Centerfold 23/24 In The Field Terminal Board Replacement .......e.ooevoerrenaoaenrorandooo rocororoaaanaco 25 In The Field Control Module Replacement ......._reonecorandoreooaoereaaaonoeaanenaocnaa 26 In The Field Tuner Module Replacement ............eeeenmerrrervererarverenrererre о 26 Removing Tunër/Amplifier Assembly From Master Unit Housing... . 1.222002 00 04 4 2 4 00 4 4 0 4 00 26 Replacing Pilot Lights .. ... 1.222001 02 11124 i it tt tt te eset eats tens tte ne a 0 0 0 4 8e 6 28 Replacement of 1/P And Door Talk Listen Switches ..... 2.202120 2 0 4 4 4 0 4 4 4 8 4 tee ee tetas 28 Bench Checking The Master Unit .. .. 1.100044 24 0 44 4 4 4 4 4 2 0 0 4 4 4 4 6 4 4 A 4 4 4 0 4 0 4 0 0 crac e 28 SYSTEM TROUBLESHOOTING CHART ..........4040 00000 a 00 000080 0 a 0 4 0 0 04 0 0 01 0 0 0 0 000 0 28 ADDENDUM Muting Circuit Modification .. ......202 02044 44 44 4 44 4 4 4 4 4 4 84 4 4 4 4 8 8 RK KR RR 30 DC Power Supply Modifications .. ..... 0200010 1104 4 14 4 2 4 8 0 4 4 8 0 4 4 4 8 4 4 4 4 Re 30 New PC Boards (Amplifier/Power Supply) .. .. 1.222020 44 44 44 4 0 4 6 0 4 4 4 4 4 8 нана неее, 32 R. F. Interference .......2 224400 00 4 4 44 1 1 1 2 14 0 8 PT 32 Setting of F.M. Squelch Control R315,.....0.200 2044440 4 8 44 4 4 6 8 8 4 6 8 0 8 4 4 4 4 0 8 0 8 a 8 10 ae» 34 REPLACEMENT PARTS LIST ......n.ecoenrmascconaraednxenaoronseonroegoacoacanvonanarnaoacanvo, 35 INSTALLATION 120 VV, 60 Hz (Class 1) {Observe Local Code) No. wo Optional: Outside Antenna Use NUTONE |A-18 INSIDE ANTENNA 3C0-CHM TWINLEAD 105-N Inside Antenna TRANSFORMER and Twinlead Supplied With 18-19 Supplied With 1R-10 SECONDARY 16V 15VA NOTE: Chime and/or Alarm should be installed in regular manner according to their specific installation No. 18:2 instructions. DO NOT power chime NuTone §-140 nor alarm from the Radio/intercom Max. 100 Ft. Earth Ground power transformer, Use Larger Wire mau For Longer Runs (No, 14/2 to ; Max. of 200 Ft.) 14 Ga. NUTONE ELECTRONIC DOOR CHIME W-2 (optional) MODEL IM-303D or IM-303L RADIO/INTERCOM MASTER in [R-10 RQUGH-IN NUTONE №2 SECURITY/ FIRE ALARM (optional) SHIELDED AUDIO CABLE Ga. usa | А {Supplied with 2603-A) re о, MODEL 2603-8 RECORD PLAYER in 2603-A FRAME (optional) No. + 120 Y, 60 Hz (Class |} {Observe Local Code} MODEL 2605-B B-TRACK TAPE PLAYER in 2603-A FRAME {optional} №. “| 120 V, 60 Hz (Class 1) {Observe Local Code) W-3 IW-3 Wa —3— 15-37 5‘ SPEAKER? CLOCK TIMER in 1R-7 15-35 INSIDE 5" SPEAKER W/CONTROLS in IR-5 No. 14/2 | 14 Ga. — Earth Ground 120 v, 50 Hz (Class 1} (Observe Local Code) 15-38D or 15-38L IMPORTANT TO AID IN REDUCING HUM AND BUZZ FROM LIGHT DIMMERS, ALL REMOTE SPEAKER WIRES AND CABLES MUST BE PLACED AT LEASE 12 INCHES FROM ANY A.C. POWER WIRING. INSIDE 8" SPEAKER W/CONTROLS in IR-8 IC-31 15-7 8 REMOTE CONTROL IW-2 INSIDE INSIDE: Install in 8" SPEAKER STANDARD 3-GANG WO/CONTROLS SWITCH BOX in IR-8 IC-31 15-79 REMOTE CONTROL IW-2 QUTSIDE OUTSIDE in 1A-19 8 N CONTROLS WEATHERSHIELD WO! in 1R-9 15.77 1C-31 OUTSIDE REMOTE CONTROL IW-2 | WEATHERPROOF OUTSIDE in 1A-19 | SPEAKER WEATHERSHIELD TO ADDITIONAL INSIDE/PATIO SPEAKERS OR REMOTE CONTROLS WO/ CONTROLS SURFACE MOUNT 2nd. DOOR SPEAKER (NUTONE IW-3-200 JW-3-10001 WIRING SPECIFICATIONS SPEAKER WIRING 'W-2 22 Ga. Twisted Pair AN INDIVIDUAL 3-WIRE CABLE [IW-3) MUST BE CONNECTED DOOR SPEAKER {IW-2-60: 60 F1. Roll} FROM EACH REMOTE INTERCOM SPEAKER CONTROL TO THE BUILTIN w. Flat Ribbon Tvoe 3Wire (22 Ga) Cable TERMINAL BOARD IN THE MASTER UNIT. 1S-61 in !R-6 — > (3.200 200 Ft. Rol) | FOR SYSTEMS WITH MORE THAN EIGHT REMOTE INTERCOM SURFACE MOUNT No. 18/2 (optional) (IW-3-1000: 1,000 F1. Roll) SPEAKER CONTROLS [MAXIMUM OF 12): oo W/PB --—. P/B TO CHIME - 15-64 ONLY No. 14/2 120 V, 60 H: Power Cable, Class 1 THE SILVER AND COPPER CONDUCTOR FROM TWO SPEAKER U.L. Listed CONTROLS MAY BE CONNECTED TO THE SAME SILVER AND {not Supptied by NuTone) COPPER (RESPECTIVELY) SCREW-ON TERMINAL ON THE | 2 | - MASTER UNIT TERMINAL BOARD. Ш a. Ground Wire 146 {Not Supplied by NuTone) THE CENTER (GROUND) WIRE IN EACH CABLE MUST BE CON- NECTED TO A SEPARATE GROUND SCREW ON THE MASTER UNIT TERMINAL BOARD. FIGURE 1: IM-303 SYSTEM INSTALLATION BLOCK WIRING DIAGRAM FOR SYSTEMS WITH MORE THAN 8 REMOTE INTERCOM SPEAKER CONTROLS: © The SILVER wires from two or = , ‚ more speaker controls may be < (1) _ AIl NuTone components are supplied with comnectd to the ame NUM. e detailed instructions and should be installed as © TheCOPPERwiefrommoor 56 directed. E tema 10 Me same COPPER BU z= 332 The CENTER wire from each NO PINOS , . ox «= speaker contro con 7 - (2) The system must be installed according to Ez “e rectedioan INDIVIDUAL the SYSTEM BLOCK WIRING DIAGRAM, Figure 1. XV The recommended NuTone wire and cable (or COPPER COPPER engineering equivalent) must be used. COPPER COPPER (3) The Inside Patio (I/P) Speakers; Door DEE a 06 Speaker(s); and when used, the Electronic Chime SONO and/or Alarm should be connected to the Master то SILVER SILVER Unit’s Terminal Board as shown in Figure 2. DOOR № sirven VER (4) NOTE: EACH REMOTE INTERCOM 1/P O, 2, 0,0, SPEAKER CONTROL MUST BE INDIVIDUALLY CONNECTED TO THE MASTER UNIT — USING DOOR - THE RECOMMENDED NUTONE FLAT RIBBON- CENTER TYPE 3-WIRE CABLE (IW-3-200 OR IW-3-1000). NO. 2272 1 CENTER (NUTONE 1W-2-60) FLAT PARALLEL J WIRE CABLE FIGURE 2: TERMINAL BOARD CONNECTIONS OPERATIONAL CHECKOUT THE SYSTEM MUST BE CAPABLE OF COMPLETING THE ENTIRE CHECK- OUT PROCEDURE. FAILURE TO COMPLETE ANY STEP INDICATES A MALFUNCTION IN PARTS(s) OF THE SYSTEM. AT RE Они =— — Nuno IE rm = lf A Behind Door |/ \ Station Selector Switches System Volume Tone Control Door Talk-Listen 1/P Talk-Listen ON Program Selector Switch AM/FM Tuning System ON/OFF Master Unit Speaker Volume FIGURE 3: IM-303 MASTER UNIT ON THE MASTER UNIT (Figure 3) (1) The TUNING KNOB; ON/OFF-MASTER VOLUME CONTROL (controls volume of Master Unit Speaker only); PROGRAM SELECTOR SWITCH; and I/P and DOOR, TALK/LISTEN CON- TROL SWITCHES are located on the front panel. (1.1) The STATION SELECTOR SWITCHES (these switches control the operating mode of the Inside/ Patio Speakers only); ALL SPEAKER VOLUME CONTROL; and TONE CONTROL are located behind the door at the lower left corner of the front panel. To open door, pull down. (2) Turn Master Unit ON: Rotaté the ON/OFF- MASTER VOLUME CONTROL clockwise — pilot lights should be turned ON. (3) Set PROGRAM SELECTOR SWITCH to AM or FM. (4) Using TUNING KNOB, tune radio to a fami- liar station. (5) Open door and set all STATION SELECTOR SWITCHES to RADIO INTERCOM position. (6) The MASTER SPEAKER VOLUME CON- TROL and the VOLUME CONTROL at every In- side/Patio Speaker Control should be set for maximum volume, i.e. full clockwise. (7) Adjust the ALL SPEAKER VOLUME CON- TROL (behind the door) for sufficient loudness at all locations. The volume in the area requiring the greatest sound level should be sufficient for that locale. (8) Adjust the MASTER SPEAKER VOLUME CONTROL and the VOLUME CONTROL on every |/P Speaker Control to the desired volume for their locales. (9) NOTE: If the 1/P Speakers” VOLUME CON- TROLS are set too low and the ALL SPEAKER VOLUME CONTROL is set too high, distortion Will result. (10) Adjust TONE CONTROL to personal pref- erence. (11) With the PROGRAM SELECTOR SWITCH in AM and FM, in-turn, rotate the TUNING KNOB through the band to check radio reception. (12) When record player and/or 8-track tape player is included in system: Use the PROGRAM SELECTOR SWITCH: select the unit being checked and play a record or tape of known quality. See the individual operating instructions that are supplied with these components. MUTING (See Addendum, Page 30) (1) Check the system MUTING by pressing in any TALK or LISTEN switch at the Master Unit or at one of the 1/P Speaker controls. (2) The entertainment program is immediately silenced when one of the switches is activated. (3) When the switch is released, the entertainment program fades back in; to full volume in approximately one-half second. INTERCOM OPERATION (1) Press the Master Units INSIDE/PATIO TALK SWITCH and talk into the Master Unit speaker. The signal should be heard at every |/Р Speaker. (2) Press the INSIDE/PATIO LISTEN SWITCH (on Master Unit only). Have another member of the family answer ‘Hands Free’ from any |/P Speaker. (Every 1/P Speaker should be checked, in-turn.) (2.1) NOTE: “HANDS FREE” ANSWERING FROM INSIDE/PATIO SPEAKERS CAN ONLY BE PER- FORMED WHEN INTERCOM CALL 1S ORIGINA- TED AT MASTER UNIT, AND iTS INSIDE/PATIO LISTEN SWITCH IS ACTIVATED. (“HANDS FREE" ANSWERING IS NEVER POSSIBLE FROM THE MASTER UNIT.) (3) Originate a call from each 1/P Speaker, in- turn. Push in the INSIDE/PATIO TALK SWITCH; and talk into the speaker. The call should be heard at the Master Unit and at all other |/Р Speakers. (4) The call may be answered from any |/Р Speaker or from the Master Unit by pushing in the INSIDE/PATIO TALK SWITCH. The answer Will be heard at the originating speaker and at all other 1/P Speakers and Master Unit Speaker. (5) Check Door Speaker(s) operation at Mas- ter Unit and at each 1/P Speaker, in-turn. Press the DOOR TALK SWITCH to talk to the Door Speaker(s). Press the DOOR LISTEN SWITCH to receive “Hands Free” answer from the Door Speaker(s). All other 1/P and Master Unit Speak- ers will hear the call and the answer. (6) Open door on Master Unit and set STA- TION SELECTOR SWITCH, in-turn, or, two or more at the same time, to OFF. (6.1) Speakers in this mode cannot receive: entertainment program; chime/alarm signals; nor intercom calls originated by other 1/P Speakers or by the Master Unit. (6.2) Speakers in this OFF mode can originate calls to the Door Speaker(s); and to the 1/P and Master Unit Speakers. However, it cannot hear a reply from these speakers. The system will be muted when a TALK or LISTEN switch at the OFF speaker is activated. (7) Set the STATION SELECTOR SWITCH for each 1/P Speaker to LISTEN IN. (One, two or more |/P Speakers may be operated LISTEN IN at the same time.) FIGURE 5: 1S-35 INSIDE 5-INCH SPEAKER 15-65 15-63 FIGURE 6: DOOR SPEAKERS (7.1) Speaker(s) in this mode will not receive: signals from chime/alarm; intercom signals; nor the entertainment program. (7.2) Sounds in the locale(s) of the 1/P Speakers in this mode will be heard - overriding the entertainment program - at all 1/P. Speakers that are in RADIO/INTERCOM mode and at the Master Unit. (7.3) If necessary, to insure “Intercom Override” of the entertainment program, an |. P Speaker in LISTEN IN may have its VOLUME CONTROL set to maximum (full clockwise). (7.4) If further override is necessary, decrease TIME/ALARM SET SPEAKER J a VOLUME CONTROL the setting of LEVEL SET CONTROL R211 — located on the Amplifier/Power Supply module. This will decrease the amplitude of the entertainment program that is fed to the audio amplifier and thus, increase the intercom signal to entertainment program ratio. The level of both signals may be readjusted with the ALL SPEAKER VOL- UME CONTROL (behind door). (8) The Master Unit speaker is not controlled by a STATION SELECTOR SWITCH. It operates the same as Inside/Patio Speakers that are in RADIO/INTERCOM mode. It can be turned OFF by turning the MASTER UNIT SPEAKER VOLUME CONTROL to full counter-clockwise position, but not past “Click.” — o: A 1/P TALK MODE SWITCH DOOR TALK-LISTEN FIGURE 7: 18-37 INSIDE 5-INCH SPEAKER/CLOCK TIMER 1S-37 INSIDE 5-INCH SPEAKER/CLOCK TIMER (1) Operation of the VOLUME CONTROL and TALK-LISTEN SWITCHES is the same as that for the other 1/P Speakers. (2) MODE SWITCH: (2.1) OFF: Entertainment program muted through entire system. Intercom operation normal, as determined by the setting of its STATION SELECTOR SWITCH in the Master Unit. (2.2) ON: Full normal operation, determined by the setting of its STATION SELECTOR SWITCH. (2.3) AUTO: Entertainment program muted. Nor- mal intercom operation. This setting used to auto- matically turn ON the entertainment program at a predetermined time. (2.4) ALARM: Same as AUTO operation except when the entertainment program is resumed, the alarm buzzer in the 1S-37 will be turned ON and will continue to sound until the MODE switch is thrown to ON (or OFF). (2.5) TIME/ALARM SET CONTROL: Rotate control clockwise (the alarm dial will turn counter- clockwise) to the time desired for the entertainment program to resume. (2.5.1) When the clock has advanced to the desired time, (as set in (2.5) above) muting of the entertainment program will be removed, and the music will resume through all speakers that are in RADIO/INTERCOM mode. (If the MODE SWITCH is set to ALARM, the alarm buzzer will also be sounded.) (2.5.2) For continuous normal radio/intercom operation, the mode switch should be returned to the ON position. (2.5.3) Clock should advance approximately 40 minutes before resetting to AUTO or ALARM position. (3) SETTING CLOCK TO CORRECT TIME: Push in the TIME/ALARM SET CONTROL and turn - in either direction - until the clock is reading the correct time. BACKGROUND MUSIC (See Addendum, Page 30) (1) The IM-303 Master Unit may be used to supply the music program source for speakers that will reproduce the entertainment program only. (1.1) THE IM-303 IS DESIGNED FOR USE WITH THE NUTONE MODEL IM-516 AUDIO AMPLIFIER. (1.2) WHEN USED WITH AMPLIFIERS OTHER THAN THE IM-516, CONTACT NUTONE'S FIELD ENGINEERING DEPARTMENT, (2) During intercom operation, the entertainment program will be muted at the 1/P and Master Unit Speakers, The intercom signals will not be heard through the “Music Only” speakers. (2.1) EXCEPTION: Since there is no muting in the system when chime/alarm signals and signals from 1/P Speakers in LISTEN IN mode are being sent through the system, these signals will be heard through the background music speakers. (3) CONNECTING THE IM-303 TO THE IM-516: (See IM-516 Installation Instructions) (3.1) IM-516 WITHIN SIX-FEET OF IM-303 Con- nect a No. 22/2 twisted-pair (NuTone IW-2-60) between the BLUE/BLACK “LOW LEVEL RADIO OUTPUT” wires in the IM-303 and the “LOW LEVEL RADIO INPUT” wires in the IM-516. The color-coded wires should be connected to the matching color coded wires in the IM-516. (3.2) IM-516 MORE THAN 6-FEET FROM 1M-303: (Maximum of 50-feet), use a shielded audio cable between the units. Connect the shield between the BLACK wires and the center conductor between the BLUE wires. (4) The IM-303 is normally operated with the OVERRIDE CONTROL R211 set to maximum. To prevent muting of the background music program during intercom operation, turn the control 10 to 15 degrees off maximum. (5) Adjust the IM-516's LEVEL SET CONTROL R6 for the desired volume at the background music speakers. | (6) After adjusting the IM-303 OVERRIDE CON- TROL, it may be necessary to readjust the Master Unit's ALL SPEAKER VOLUME CONTROL, and in some cases, the MASTER UNIT SPEAKER VOL- UME CONTROL and the VOLUME CONTROLS on the individual 1/P Speakers. CHIME/ALARM OPERATION (1) Press the chime pushbutton at entrance, the chime signal should be heard through the Master Unit Speaker and through all 1/P Speakers that are in RADIO/INTERCOM mode. (2) Check the alarm system (see individual operating instructions supplied with the individual alarm systems), the alarm signal should be heard through the Master Unit Speaker and through all |/P Speakers that are in RADIO/INTERCOM mode. THEORY OF OPERATION (See Center Fold for Schematic Diagram, Wiring Diagram and PC Boards) POWER SUPPLY (See Addendum, Page 30) (1) The Power Transformer (NuTone Model! 105-N) is supplied with the IR-10 rough-in housing and should be located remote from the Master Unit — near power panel, etc. (2) The 105-N is rated at 120Vac, 60 Hz. primary input and at 16Vac, 15 VA secondary output. (3) The secondary of the power transformer may be connected to the Master Unit by 100 feet (maximum) of No. 18/2 cable (NuTone S-141). For runs up to 200 feet, use No. 14/2 cable (not supplied by NuTone). (4) Terminal 2 of J4 should be connected to earth ground. (5) The 16Vac is turned ON (or OFF) by the ON/OFF SWITCH S101 (operated by the shaft of the Master Unit Speaker Volume Control R101). (6) When S101 is ON, the 16Vac is applied to the series circuit of PL103; R108; PL102; R109 and PL103. R108 and R109 limit current through the lamps. (7) The 16Vac is applied to Z201 (Z201 includes D203; D204; D205; and D206) full-wave bridge rectifier. The output of the bridge is filtered by C209 and results in Vcc of +22.5Vdc. (7.1) Capacitors: C207; C208; and in later production units, C221 and C222 bypass the high frequency switching noise that may be generated by the diode rectifiers. | (8) The +22.5Vdc is connected to the voltage regulator circuit, R235; R239; Q209 and Zener diode D210. R239 limits Q209 collector current. Although Q209 is a heavy duty device, shorting of the Regulated 11.5Vdc must be avoided. The 11.5Vdc powers the AM-FM Radio Module. (9) The regulated 11.5Vdc is switch by SELEC- TOR SWITCH $102 to the AM or FM tuner and IFs, and is open ended when in PHONO or TAPE position. (10) 12Vdc at the junction of Q209 base and cathode of D210 is connected through R237 to supply muting voltage: to the control circuit of 15-37; and through the Inside/Patio LISTEN SWITCH S103 to Q210 when set is bench checked and the Control Module is not installed. RADIO MODULE (1) The Radio Module includes the complete AM and FM tuners. (2) When S102 is in AM position, the regulated +11.5Vdc is fed through P1-2/J1-2 to the AM tuner. (3) When S102 is in FM position, the regulated +11.5Vdc is fed through P1-3/J1-3 to the FM tuner. FM TUNER ‚ (1) The FM signal is fed through the coaxial antenna lead-in to the balanced primary of the antenna transformer L301. The transformer primary is center tapped to FM RF ground through C301. (2) The RF amplifier Q302 (Dual gate MOSFET) is operated tuned-gate, tuned-drain — resulting in high-gain at low noise. (3) The FM RF signal is fed through a section of the antenna transformer secondary through C304 to G1 of Q301. The gate tuned circuit is varied by tuning one section of the ganged tuning capacitor C303A. C303B is the high-frequency trimmer. Tuning slug in L301 is tuned for low- frequency padding. (4) The MOSFET drain is loaded by the tuned RF tank circuit. The tank’s resonant frequency is varied by C303F. C303E is high-frequency trimmer and L302 is low-frequency padder. (5) The output of the tank circuit is coupled through C310 to the base of the Mixer 0302. (6) The oscillator Q303 resonant frequency is tuned by C303J. C328 is high-frequency trimmer and L303 is adjusted for low-frequency padding. (7) The output of the oscillator is coupled through C327 to the base of Mixer Q302. (8) The Mixer Q302 beats the RF and oscillator signals and is loaded by T301A tuned to the 10.7 Mhz. IF frequency. (9) For additional selectivity, the output of T301A is coupled through C314 to T301B. (10) The output of T301B is coupled from the highside of C315 to the Ceramic Filter CF301. (11) CF301 is rated at 10.7 Mhz. with a 3 db bandwidth of 200 to 280 KHz. — more than sufficient for the FM broadcast band. The filter has a very high rejection of all other RF frequencies, eliminating the need of additional IF transformer for high-selectivity. (12) Z301. (13) Z301 is a monolithic integrated circuit that provides all the functions of a comprehensive FM IF system, including 3-stage FM IF amplifier/ limiter with level detector and an audio amplifier that features use of a noise squelch circuit. The output of CF301 is fed to terminal 1 of —8— (14) The quadrature detector is tuned by the out- board coil L304. (15) The squelch circuit is adjusted by R315. Use of the squelch circuit helps to eliminate side responses that are characteristic of limiter-discriminator type FM receivers. (16) Suppression of these side responses per- mit the design of an FM receiver that tunes as easily as an AM tuner without resorting to AFC — where AFC is not required to correct for oscillator drift. (17) The FM oscillator in this system has been designed with quality components and with the use of the regulated 11.5Vdc supply should be practically free of drift under normal operating conditions. (18) The magnitude of the squelch control voitage depends only on the signal-to-noise ratio at the tuner input and is essentially independent of the front-end gain because the quadrature signal is fully limited. (19) Adjustment of the “Squelch Threshold” control affect primarily the degree of noise suppression rather than the threshold. Control R315 is generally operated at maximum value, i.e. full- clockwise as viewed from the FM side of the Radio Module PC Board. (See Addendum, Page 34) (20) VR301 protects the FM and AM front end from static discharge and nearby lighting. It will not protect the set from a direct lighting strike. AM TUNER (1) The AM signal is fed from the center tap of the FM antenna transformer primary, through R331 to the tuned RF circuit. (2) The RF circuit is tuned by gang capacitor C303D. C303C is the high-frequency trimmer and coupling of L309 is adjusted for low-frequency padding. (3) Delayed AGC is supplied from pin 15 of Z302, through R329 and across D301 to ground. When the signal increases beyond desired level, the diode will conduct, changing the impedance of the input circuit and tend to swamp the AM signal. (4) The output of the tuned RF circuit is fed through C333 to pin 2 of Z302. (5) Z302 is a monolithic integrated gjrcuit pro- viding AM convertor; IF amplifier and detector. In this application it also supplies AGC to the first IF stage and delayed AGC to the RF tuned circuit, (6) Pin 2 of Z302 is the base of the oscillator/ converter stage. (7) The oscillator tank is tuned by varying C303G. C303H is the oscillator trimmer and L310 oscillator collector coupling is adjusted for low frequency padding. (8) The oscillator/ converter output is loaded by the 455 KHz. IF transformer T302. The output of T302 is fed through Ceramic Filter CF302 to the input of the first IF stage in the IC Z302. (9) The amplified output of the first IF stage is fed from Pin 6 through CF303 to the input of the second IF amplifier and second detector. (10) CF302 and CF303 Ceramic Filters’ center frequency is 455 KHz.+ 2 KHz. with a 3 db band width of 10 KHz. + 3 KHz. with a frequency stability within 0.4% from —10°C to +80°C. (11) Use of these filters provides improved selectivity; the elimination of IF transformers and the resulting small space. AUDIO CONTROLS: (1) SELECTOR SWITCH $102; One side of this switch selects the audio entertainment program that is fed to the audio amplifier. (1.1) The other side of the switch controls the regulated 11.5Vdc to the AM and FM RF and IF stages — driving the tuner that is being used. When the switch is in PHONO or TAPE, the +11.5Vdc is open ended and, neither the AM nor FM tuner has voltage applied. (2) The AM program, from P1-1 through R233, is selected when S102 is in number 1 (top) position. The +11.5Vdc is fed to the AM tuner through P1-2. (3) The PHONOGRAPH signal is fed through PHONO INPUT J104 and is loaded by C103 and R107 to the number 2 position of S102. C103 and R107 supply the correct load for the cartridges used in NuTone record changers. (4) The TAPE PLAYER signal is fed through TAPE INPUT J105 and is loaded by R106 through the number 3 position of S102. The tape input matches the NuTone Tape Players. (5) The FM program through P1-4 and R234 is selected when S102 is in the number 4 (bottom) position. The regulated +11.5Vdc is fed to the FM tuner through P1-3. (6) The common audio terminal of S102 feeds the audio program to the LOW LEVEL RADIO OUT- PUT connection, and through C206 to the high side of the 2.2 Megohm LEVEL SET CONTROL R211. (7) The LOW LEVEL RADIO OUTPUT may be used to drive NuTone's Model 516 background music amplifier. This entertainment program will (12) C337 is the internal AGC filter. (13) The recovered audio is fed from the detector output through R326; J1-1/P1-1 and R233 to the AM terminal on S102. ALIGNMENT (See Page 10/11) (1) The Master Units are shipped from the factory completely aligned. (2) Alignment should be performed by qualified personnel ONLY WHEN ABSOLUTELY NECES- SARY. (3) Use the alignment method recommended in this manual. INPUTS AND OUTPUTS not be interrupted when the system is being used - for intercommunications through the standard speakers (15-35, 19-38, etc). (7.1) The LOW LEVEL RADIO OUTPUT is engi- neered for use with NuTone's Model 516 Audio Amplifier. When it is to be used to drive other amplifiers, consult NuTone's Field Engineering De- partment for specific details. —9— (8) The wiper contact of R211 is fed through R210 and a shielded cable to the TONE CONTROL CIRCUIT C101/R102 and the SYSTEM VOLUME CONTROL R103, and back through another shielded cable; R212; and coupling capacitor C212 to the base of the first audio amplifier Q203. (8.1) The wiper of R211 is also connected to the collector of the muting transistor Q210. When Q210 is turned ON [Veb(sat)], its collector is effec- tively at ground potential and the audio on R211's wiper will be shorted out. (9) When the LOW LEVEL RADIO OUTPUT is used to drive a background music amplifier, R211 should be backed off 10° to 15° from its maximum (normal) setting. This will prevent shorting of the entertainment program at the high-side of R211. (10) THE INTERCOM SIGNAL: from Door Speak- er(s); Inside/Patio Speaker(s); Master Unit Speak- er, and when used, chime and/or alarm is fed through the intercom input Transformer T201 and C201 to the base of intercom preamp Q201. (11) T201 has a voltage step-up of 84 and Q201 has a voltage gain of 17. The amplified intercom signal is coupled through R208 — reducing the signal by a factor of 33. (11.1) Q201's gain is not used. This stage's primary function is to determine the frequency characteristic of the intercom signal and to isolate the input transformer from the first audio amplifier Q203. (12) The collector of Q202 is connected to the junction of R208; C212 and the audio input from R103. When the positive “Key Click” suppression voltage — from the Control Module — is applied to the base of Q202, it will be turned ON and short the audio signal (that is present on its collector) to ground. (13) The diodes D201 and D202 protect the secondary of T201 from excessive transient voltages that may be generated during intercom switching. TUNER ALIGNMENT This receiver should be aligned ONLY WHEN ABSOLUTELY NECESSARY and ONLY BY QUALIFIED PERSONNEL. Use non-inductive, low-capacity alignment tool when making adjustments. F. M. ALIGNMENT MASTER UNIT SETTINGS: 1. SELECTOR SWITCH S102 in FM. 2. ALL SPEAKER VOLUME CONTROL R103 set to desired level. 3. SEQUELCH CONTROL R315 {located on Radio Module board) set to minimum (full counter-clockwise position as viewed from F.M. Side of PC board). INSTRUMENTS REQUIRED: 1. CATHODE RAY OSCILLOSCOPE 1.1 High side of vertical input connected through a 15K % watt resistor to tuner’s F.M. Audio output, J/Pi-4. NOTE: DO NOT TOUCH THE REGULATED +11.5 Vdc TERMINAL J/P1-3. DO NOT SHORT THE VOLTAGE TO GROUND. SHORTING THE +11.5 Vdc MAY RESULT IN DESTROYING THE VOLTAGE REGULATOR 0209 AND THE 12V ZENER DIODE D213. 1.2 Low (ground) side of vertical input connected to Radio Module ground. 1.3 Use 60 Hz. horizontal sweep. If scope does not have own 60 Hz. horizontal, use exterior source. 2. FM SIGNAL GENERATOR 2.1 Modulate RF output with 60 Hz. at 400 KHz. sweep width. 2.2 Connect 60 Hz. to scope's horizontal input if required. 2.3 Connect a 50 ohm resistor across RF outputof signal generator. 2.4 Connect high-side from generator to center conductor of coax antenna lead-in. 2.5 Connect low-side (ground) from signal generator to shield (braid) of coax. Step | Signal Generator Setting Receiver Setting Adjust | Tune For 1. | 106 MHz. @ 2 to 5 microvolts. Tune receiver (ganged tuning L304 Quadrature coil. Detune Maximum trace on scope as (If generator does not have capacitor to pick up signal coil to get wave form as shown shown in “A” below. Sacrifice calibrated output, use lowest generator). in “A” below. If wave is gain for linearity and flat top. If level consistent with good trace negative, reverse direction of necessary, reduce output from on scope.) slug detuning, signal generator to prevent receiver limiting. 2. 108.5 MHz. F.M. Tuning Dial to 108.5 MHz. C328 Oscillator Trimmer do {Ganged Tuning Capacitor fully opened.) 3. F.M. Tuning Dial to 87.5 MHz. Frequency of RF output from do ‘ (Ganged Tuning Capacitor fully Signal Generator. (Should be in closed.) neighborhood of 87.5 MHz.) IF, INSTEP 3 ABOVE, FREQUENCY OF SIGNAL GENERATOR IS VERY CLOSE TO 87.5 MHz 4(a) | 87.5 MHz. F.M. Tuning Dial to 87.5 MHz. L303 Oscillator Coil do (Ganged tuning Capacitor fully closed.) IF, IN STEP 3 ABOVE, FREQUENCY OF SIGNAL GENERATOR 1S BELOW 87.5 MHz. {87 MHz or lower) 4(b) | Slightly decrease the inductance of L303: Turn tuning slug approximately 1/8 turn counter clockwise. Repeat steps 2 and 3 above. IF, IN STEP 3 ABOVE, FREQUENCY OF SIGNAL GENERATOR IS ABOVE 87.5 MHz. (88 MHz. or higher) 4(c) | Slightly increase the inductance of L303: Turn turning slug approximately 1/8 turn clockwise. Repeat steps 2 and 3 above. 5. Repeat 2 and 3 above until oscillator is rocked in at both ends of dial. 6. 106 MHz. F.M. Tuning Dial to 106 MHz. C303B RF Input Transformer do 303E RF Qutput Trimmer T301A and T301B, Mixer 10.7 MHz. IF Output. 7. | 90 MHz. F.M. Tuning Dial to 90 MHz. L301 Antenna Input do Transformer: Two peaks may be noted while adjusting this slug. USE THE PEAK WITH THE SLUG POSITIONED NEAR THE BOTTOM OF THE COIL. L302 RF Amplifier Tank Coil 8. Repeat steps 6 and 7 until no further improvement in scope trace is noted at either setting. As the set is aligned, it may be necessary to reduce output of Signal Generator to prevent receiver limiting. 9. | 90 MHz. @ 10 microvoits. {If F.M. Tuning Dial to 90 MHz. L304 Quadrature Coil. Maximum symmetrica: “S” uncalibrated, use sufficient curve. See “B” below. Curve signal strength to drive receiver should be linear and equal into limiting. distance above and below the reference line on scope. 10. | Step 9 should be checked for various frequencies across the F.M. band. Check limiting by increasing the output of the signal generator, the 'S” curve’s amplitude should remain the same. 11. Disconnect signal generator and (if used) external sweep to scope. Scope should use regular horizontal sweep. “Tune receiver between stations. Note noise at J/P1-4 (as seen on scope). Turn R315 fuli clockwise for maximum squelch. Noise should disappear and straight line horizontal trace be seen on scope. — A.M. ALIGNMENT MASTER UNIT SETTINGS: 1. SELECTOR SWITCH S102 in AM. 2. ALL SPEAKER VOLUME CONTROL R103 set to desired level. INSTRUMENTS REQUIRED: 1. CATHODE RAY OSCILLOSCOPE 1.1 High side of vertical input connected through a 15K ' watt resistor to tuner's A.M, Audio output, J/P-1. NOTE: DO NOT TOUCH THE REGULATED +11.5 Vdc TERMINAL J/P1-2. DO NOT SHORT THE VOLTAGE TO GROUND. SHORTING THE +11.5 Vdc MAY RESULT IN DESTROYING THE VOLTAGE REGULATOR Q209 AND THE 12V ZENER DIODE D213. 1.2 Low (ground) side of vertical input connected to Radio Module ground. 1.3 VTVM may be used but, recommend Oscilloscope so that linearity as well as amplitude of the audio signal may be observed. 2. AMSIGNAL GENERATOR 2.1 Modulate RF output with 400 Hz. @ 30%. 2.2 Connect high-side of generator output through 200 pf. (ceramic or mica) capacitor to shield (braid) of coax antenna lead-in. | 2.3 Connect low-side (ground) of generator output to Radio Module ground. Step | Signal Generator Setting Receiver Setting Adjust Tune For 1. 537 KHz. Use signal level AM Tuning Dial to 537 KHz, 1.310 Oscillator Padder Coit” Maximum sine wave trace required. Do not overdrive. (Ganged Tuning Capacitor fully on scope. (or maxi-voltage on closed) VTVM) 2. | 1620 KHz. AM Tuning Dial to 1600 KHz. C303H Oscillator Trimmer do (Ganged Tuning Capacitor fully opened) 3. | Repeat steps 1 and 2 until no further improvement can be made and oscillator tunes at both ends. 4. | 600 KHz. | AM Tuning Dial Set to 600 L309 AM Antenna Transformer do KHz. 5. | 1500 KHz. AM Tuning Dial Set to 1500 C303C Antenna Tuning do KHz. Trimmer Repeat steps 1 and 2 until no further improvement can be made and RF tuning tracks across the band. 7. i 1500 KHz. AM Tuning Dial Set to 1500 T302 AM IF (455 KHz.) do KHz. Transformer (*} May be tuned to two pezks: One peak with slug at top of coil and other peak with slug near bottom of coil. Recommend use of peak with slug near bottom of coil. DIAL CORD INSTALLATION —11— AUDIO AMPLIFIER (1) The amplifier is powered by the +22.5Vdc supply (Vcc). (2) The audio signal(s) from the intercom preamp Q201 and/or the volume control R103 is fed through C212 to the base of the first audio voltage amplifier Q203. This stage has a gain of 7. Its output is direct coupled to the base of Q204, the second audio amplifier. (3) The second audio amplifier operates with no gain, in fact, the signal is reduced approximately 20% through the stage. It has a very high input impedance and its dynamic characteristic is very important in determining AC and DC feedback; and in conjunction with C214 the high-frequency response of the amplifier. (4) The output of Q204 is direct-coupled to the Darlington connected amplifier-driver Q205 and Q206. This Darlington combination has a gain of 270. The no signal collector current of Q205/Q206 “generates a slight forward bias to the power output transistors Q207 and Q208. (4.1) This bias is generated across D207 and R226. D207 is a temperature tracking diode mounted on the amplifier's heat sink. (5) With the slight forward bias on Q207 and Q208, they are operated Class AB complimentary. The AB operation helps eliminate notch crossover distortion in the output stages. Q207 and Q208 have a very high current (power) gain. They are mounted on the heat sink. (6) If the output transistors draw extra current — resulting in greater heat dissipation through the heat sink — D207’s cathode to anode voltage decreases. With the decrease in diode voltage drop, the forward bias on Q207 and Q208 decreases, resulting in a decrease in collector current, thus, tending to stabilize the operating condition of the output transistors. (7) To overcome the high input impedance of Q208, the bootstrapping capacitor C218 is coupled from its output to the junction of R228 and R229. (8) The Amplified Audio Output is coupled through C219 to the load. The circuit is protected against shorts on the speaker side of C219 by the diodes D208 and D209 which under short circuit conditions, limit the current through Q207. Q208 is protected by its high input impedance. (9) AC degeneration is coupled through R224 to the emitter of Q204. (10) The overall gain of the amplifier — Q204 through Q207/Q208 — is controlled by the ratio of the resistance of R224/R222. The gain is approximately 183. If R222 is shorted, the gain should increase by a factor of 24. (10.1) It may be desirable when servicing some types of trouble to short R222 and observe the signal at various points without the influence of negative feedback. (11) DC STABILITY: R216 and R218; and R217 form a voltage divider from Vcc to ground and the base of Q204. Q204 base bias voltage is approximately one-half Vcc. (12) When Q204 collector current increases, Q205/Q206 bias current increases and results in an increase of collector current. (13) As Q205/Q206 collector current increases the collector voitage rises to near Ve (Vec). This increases the forward bias on Q207 and Q208. (14) When forward bias on Q207 and Q208 is increased, their collector currents are increased and the voltage at the junction of their emitter resistors R232 & R231 goes toward Vcc. (15) This junction voltage is fed through R224 to the emitter of Q204, as this voltage increases Q204’s forward bias is decreased and the collector current decreases. If the output center voltage rises above Q204’s base voltage, Q204 will be turned OFF, thus reversing the action of para (11) - (14) above. (16) If the output center voltage should attempt to stabilize much below the base bias on Q204, Q204 will conduct harder and force the center point voltage to rise. (17) Unless there is a failure of component(s), the 100% DC feedback will lock the DC operating voltages at their designed values. (18) EXAMPLE: Q206 develops an emitter-collector short. The base voltage of Q207 would be equal to Vcc and the emitter voltage about the same (the increased positive voltage on the base of Q208 would tend to clamp it off). The very high voltage at the junction of R231 and R232 will be fed back to the emitter of Q204, and even though Q204's base remained clamped on one-half of Vcc, the high voltage (approximately full Vcc) fed to the emitter would reverse bias Q204 and keep it turned F. CONTROL MODULE & INTERCOM SWITCHING FOR THE FOLLOWING DISCUSSION, SEE THE SCHEMATIC DIAGRAM AND THE IM-303 SYSTEM INTERCOM SWITCHING & CONTROL DIAGRAM (1) The Control Module is powered by the 22.5Vdc supply (Vcc) that is fed through J/P2-2 from the Amplifier/Power Supply Module. (2) The Quad Amplifier Integrated Circuit Z401 is operated as four individual voltage comparators: Z401A; Z401B; Z401C; and Z401D. They control the intercom switching operation. —12— (3) A positive ( +) reference voltage is applied to the positive (+) input terminal of each comparator. These potentials are derived from the voltage divider network: R404; R403; R402; and R401 (all part of resistor pack 2403). The actual voltages on the positive terminals of the comparators will be somewhat less than those measured at the divider resistor terminals. The 1 Megohm resistors: R408—R414 limit the input current of their respective comparator: The resistor pack voltages: Terminal 5 14.5V Terminal 6 9.4V Terminal 7 3.9V Terminal 4 17.5V (Control Line Point “X”) (4) The CONTROL LINE'S normal voltage, i.e. when no intercom function is being used, is +17.5V. This voltage is connected to the negative (—) terminals of the comparator amplifiers (through 1 Meg resistors), keeping them clamped OFF. (5) When the DOOR LISTEN switch in an 1/P Speaker is activated, point “X” is connected through R502 and D505, and then through the originating I/P Speaker Control's R2 (8.2K) and common to INPUT GROUND. The voltage at point - "X” goes to 9.9V; Z401A is turned ON and its terminal 9 goes to 13.5V. The other three comparators remain OFF. (5.1) The 13.5V from terminal 9 is fed through D408 to the base of Q402. The diode D411 between base and emitter keeps a reverse bias on Q402 and it is clamped OFF. The voltage charges C404 and this charging voltage is fed through D412 to point “W”. The voltage at “W” is fed through J/P2-3 to the base of KEY CLICK SUPPRESSION transistor Q202, turning it ON. When Q202 is turned ON, the collector goes to approximate ground (emitter potential), and the audio on Q201's collector and that on Q203's base will be shorted out. (5.2) This voltage appears at “W'”' only during the charging time through C404, and keeps Q202 turned ON for approximately 150 milliseconds. This is sufficient to eliminate most of the switching noises, allowing just enough “Click” to keep the operator aware that intercom switching is taking place. (5.2.1) When the Door Listen switch is released, the voltage through D408 and D411 is eliminated, and the capacitor C404 discharges through the now forward biased Q402. This discharging voltage is coupled to Q202's base and suppresses ‘Key Clicks” when switch is opened. (5.2.2) The KEY CLICK SUPPRESSION VOLTAGE can be measured at J/P2-3. On a standard 20K ohm/volt multimeter, and it will read between .25 and .35 volts. The actual voltage as seen on a scope will be approximately .8 volts @ 150 to 200 millisecond pulse width. (5.3) The 13.5V from terminal 9 will also be fed through R419 and D407 to “U”. The voltage “U” is fed through J/P2-5 and D211 to the base of Q210, turning it ON. When Q210 is ON, its collector is at ground and the entertainment program is MUTED. This voltage will remain on “U” while the DOOR LISTEN switch is held closed. This voltage is .7 on Q210 base and 1.4 at J/P2-5. (5.4) When the switch is released, the voltage at “U” will decay at an RC rate and the voltage on Q210's base will fall through saturation to turn OFF, and the entertainment program will fade- back, in something less' than 1/2 second. (5.5) The 13.5V from Z401A terminal 9 is also fed through R418 and the Audio Switching diode D410; then through J/P2-6 and Input Transformer T201 to INPUT GROUND. (5.6) When D410 is turned ON, the DOOR SPEAKER LINE'S audio, coupled through normal contacts of K401 and C403; superimposed on the forward biased D410 to the Intercom input Trans- former T201. The audio signal from the Door Speaker will be amplified and heard by the Master Unit speaker and all 1/P Speakers that are in RADIO/INTERCOM mode. (5.6.1) (NOTE) The 1/P Speakers mode of operation is controlled by the Station Selector Switches: S501—S508, located on the Terminal Board in the Master Unit. (5.7) When the DOOR LISTEN switch is released, D410 is turned OFF and an audio signal that may be picked up by the Door Speaker(s) will be blocked from the Input Transformer T2071. (6) When the DOOR TALK switch in an 1/P Speaker is activated, point “X” is connected through R502 and D505; through Rt and the speaker voice coil; and through common to INPUT GROUND. The voltage at “X” goes to approximately 5V. Z401B and Z401D are turned ON. Quad comparator terminal 4 goes to 11.3V and terminal 10 goes to 11.3V. (6.1) The 11.5V from terminal 4 is fed through D404, to terminal 8 keeping Z401A turned OFF. Voltage at “X” is still too high positive to allow Z401C to be turned ON. (6.2) The 11.5V at terminal 4 is also fed through R417 to the base of Q401, turning it ON which activates DOOR RELAY K401, which now connects the high side of the Door Speaker(s) through the relay contacts and J/P2-4 to the Audio Output. The other side of the Door Speakers will be connected through common to OUTPUT GROUND. (6.3) The 11.5V at terminal 10 is fed through D409 to the MUTING and KEY CLICK SUPPRES- SION circuits. These circuits operate as described in (5) above. (6.4) The 11.5V from terminal 10 is also fed through R416; J/P2-9 and to Audio Switching diode D501 — turning it ON. Talking into the originating 1/P Speaker, will result in the audio signal bypassing R1 through C1; through the turned on diode D501; J/P3-1; J/P2-9; C402; and J/P2-6 to the high side of T201. The common from the originating 1/P Speaker is connected to the INPUT GROUND. (6.5) Both the Door Speaker and 1/P audio signal will be heard at all other 1/P Speakers when they are in RADIO/INTERCOM mode, and at the Master Unit Speaker. (7) When the 1/P TALK switch in an 1/P Speak- er is activated, point “X” is connected through R502 and D505; through the I/P TALK switch and the speaker voice coil; and then through common to the INPUT GROUND. The voltage at “X” goes to 2 volts and Z401C and Z401D are turned ON. The voltage at Z401 terminal 5 goes to 13.5 and at terminal 10 goes to 13. | (7.1) The 13.5 volts from terminal 5 is fed through D402 to the negative (—) terminal of Z401B and through D404 to the negative terminal of Z401A,. keeping these amplifiers clamped OFF. (7.2) D403 and D401 are blocking diodes, keeping the controlled voltages from the ON sections of the quad comparator from the Control Line. (7.3) The 13 volts from terminal 10 is fed through D409 to the MUTING and KEY CLICK circuit as described in (6.3) and (5) above. It is also fed to D501 turning it ON. (7.4) The audio signal from the originating speaker is fed through the SILVER and CENTER (INPUT and COMMON) leads and through the turned on D501 to the Intercom Input Transformer T201. (7.5) Audio signals sent from the |/P Speaker will be heard at all other IP Speakers in RADIO/ INTERCOM mode and through the Master Unit Speaker. (8) The Master Unit's DOOR LISTEN: DOOR TALK: and 1/P TALK operations are the same as for an I/P Speaker, EXCEPT: Its control line is fed through control diode D508; and its “Talk” path is through Audio Switching diode D504. (9) The Master Unit Speaker is always in RADIO/INTERCOM mode. It can be silenced both for talking and listening by turning its volume control R101 to minimum (full counter-clockwise). Do Not turn past “Click ” except when turning entire system OFF. (10) MASTER UNIT INSIDE LISTEN: When 5103 is activated, all 1/P Speakers that are in RADIO/ INTERCOM mode will have one side (OUTPUT SILVER) connected through J/P3-7; one side of S108; J/P3-5 to Audio Switching diode D504 and the I/P TALK INPUT LINE; J/P2-9; C402; and J/P2-6 to the high side of T201. (10.1) D504 is turned ON by the CONTROL LINE being connected through R502 and D508; J/P3-5; S103; J/P3-7; out the SILVER lead to the 1/P Speakers and then through common to INPUT GROUND. This causes point “X” to go to approximately 2 volts-turning ON Z401C and Z401D. (S1.03 in effect acts as an 1/P TALK switch in the I/P Speakers. The |/P Speaker(s) will now talk back through the INPUT, SILVER wire through S103. (10.2) The MUTING and KEY CLICK SUPPRES- SION acts the same as in any other intercom function. (10.3) The Master Unit Speaker remains connected between audio output and OUTPUT GROUND. (10.4) If the Control Module is removed from the chassis, the MUTING operation can be checked by depressing S103. The MUTING LINE (B) will be connected through S103 to the base of Q210-sil- encing the entertainment program. (10.5) When S21 in the 1S-37 Clock Timer Control is closed the MUTING LINE (B) voltage will be connected to base of Q210. TERMINAL BOARD (See Schematic Diagram) (1) Provides convenient connecting points for wires and cables from auxiliary equipment. (1.1) CHIME/ALARM INPUT: One wire to this terminal and other wire to one of the COMMON terminals. The high side is connected through isolating resistor R501; and J/P3-3 to the high side of T201. The common side is connected to INPUT GROUND. (1.2) DOOR SPEAKER: One side to DOOR terminal and other side to one of the COMMON terminals. The high side is connected through J/P3-6; and J/P2-7 to the common terminal of DOOR RE- LAY K401. The common side is connected to INPUT GROUND or OUTPUT GROUND, depend- ing on its operation. (1.2.1) Two or three Door Speaker(s) may be connected to the DOOR terminal and the same COM- MON terminal. All Door Speakers are operated in the same mode at any one instant. (1.3) 1/P SPEAKERS: Maximum of 12 1/P Speak- er Controls may be connected in the system. (1.3.1) EACH 1/P SPEAKER CONTROL'S COM- MON (CENTER) CONDUCTOR MUST BE CONNECTED TO AN INDIVIDUAL COMMON TERMINAL. (1.3.2) The OUTPUT (SILVER) conductor from each 1/P Control should be connected to an individually numbered OUTPUT (SILVER) terminal. In systems With more than 8 1/P Controls, the SILVER leads from two 1/P Controls may be connected to the same OUTPUT terminal. Speakers connected to the same terminal will be operated in the same mode as determined by the setting of the corresponding Station Selector Switch (S501—$S508). (1.3.3) The INPUT (COPPER) wire from each |/P Control should be connected to an individual INPUT terminal. (1.3.4) When four or less 1/P Controls are used, connect the COPPER wires to only one of each pair of COPPER terminals. Divide the load. (1.3.5) When more than eight 1/P Controls are used, connect the COPPER wire from two 1/P Con- trols to the same terminal, again dividing the load. (2) STATION SELECTOR SWITCHES S501— 5508: Control the operating mode of the I/P Speakers connected to the corresponding OUT- PUT terminal. (2.1) Position 1, LISTEN IN: Connects the I/P Speaker's OUTPUT (SILVER) wire through J/P3-3 to the high side of T201. The common side will be connected to INPUT GROUND. (2.1.1) Any sounds in the vicinity of speaker(s) in this mode will be amplified through the system and will be heard by the Master Unit speaker; and by —14— other 1/P Speakers that are in RADIO/INTERCOM mode. Signal should override the entertainment program. (2.1.2) For Additional override, decrease the volume of the entertainment program by adjusting LEVEL SET CONTROL R211 on the Amplifier/ Power Supply Module. This will increase the intercom to entertainment volume ratio. The level of both signals may be readjusted with the ALL SPEAKER VOLUME CONTROL R108. (2.1.3) Speakers in this mode will not hear: Chime/ Alarm signals; the entertainment program; nor messages sent by the Master Unit and by other 1/P Speakers. (2.1.4) Activating the TALK and LISTEN switches of speakers in the LISTEN IN mode will activate the comparator amplifiers, muting and key click suppression the same as when speaker is in RADIO/ INTERCOM mode. (2.1.5) The 1/P Speaker will be able to talk to the Door Speaker with muting, but will not be able to hear the Door Speaker answer. (2.1.6) The LISTEN IN speaker will be able to talk to the Master Unit and to other 1/P Speakers that are in RADIO/INTERCOM mode but, will not be able to hear their answer. (2.2) Position 2, OFF: 1/P Speakers in this mode Will not be able to hear any signals from any source. (2.2.1) These 1/P Speakers can activate the comparator amplifier(s), muting and key click suppression, and can talk to: The Door Speaker(s); the Master Unit Speaker; and to other 1/P Speakers that are in RADIO/INTERCOM mode. BUT, THEY CANNOT HEAR ANY REPLY. (2.3) Position 3, RADIO/INTERCOM: |/P Speak- ers in this mode have full intercom capability; can hear Chime/Alarm Signals; and can hear entertainment program. (2.3.1) They will receive signals from other 1/P Speakers that are in the LISTEN IN mode or OFF mode. (3) The Control Line is protected from high voltages, that may be built up by static etc., by 36V Zener diode D509. (3.1) The INPUT (COPPER) line is protected from voltages in excess of 90 volts by the voltage regulator lights VR501—VR504. This will protect the contro! and audio switching diodes D501 and D508 from eXcessive reverse voltages. (3.2) The control diodes D505, D506, D507 and D508 act as one-way switches for the Control Line voltages to the I/P Speakers D508 also serving the Master Unit Speaker. (3.3) The audio switching diodes, D501, D502, D503 and D504 act as one-way audio switches. When they are forward biased, they allow the intercom signal from the various |/P speakers to be fed to the Input Transformer T201. When they are not biased, they prevent any noise on the line from being fed to the amplifier. D504 also serves the Master Unit Speaker. SERVICING THE IM-303 SYSTEM GENERAL (1) The modular construction employed in the IM-303 Master Unit encourages in-the-field servicing. (2) The Control Module; Tuner Module, and Terminal Board can be easily replaced, in-the- field, without soldering of any wires or connections. (See below) (2.1) The replacement Tuner Module supplied by NuTone is aligned at the factory. (3) From the top of the Master Unit Housing, remove the Retainer Pin — pull up. (Figure 8, Pg. 16) (3.1) Tip the complete chassis down and hold in a horizontal position with the support strap. (4) The plugs/jacks connecting the various as- semblies will be exposed for easy access. (5) Many of the operating voltages referred to in this manual can be measured at the plugs/jacks and other terminals without removing the Master Unit from its installation. (6) Although a standard 20K ohm/volt multimeter will suffice for most voltage and resistance measurements in this system, it is suggested that, —15— when available, high-impedance input meter (such as a VTVM) be used. (7) A VTVM with a dc scale of 0 to 1.5 volts will be especially useful when measuring base and emitter voltages. (8) The voltages included with the various dia- grams may vary +10% to =20%. THE RELA- TIONSHIP BETWEEN THE VOLTAGES ON THE DIFFERENT ELEMENTS SHOULD REMAIN FAIRLY CONSTANT TO ACHIEVE DESIGN PER- FORMANCE. (9) To prevent leakage paths when measuring resistance of some components, it may be necessary to disconnect one side of the component under measurements. (10) MAKE CERTAIN THAT POWER IS RE- MOVED WHEN MEASURING RESISTANCE OR WHEN REMOVING OR REPLACING COMPO- NENTS ON THE PRINTED CIRCUIT BOARDS. (11) OBSERVE OHM-METER POLARITY WHEN MAKING RESISTANCE MEASUREMENTS IN TRANSISTOR CIRCUITS. IMPROPER POLARITY MAY RESULT IN FALSE READINGS AND IN SOME CASES THE VOLTAGE OF THE OHM- METER MAY EXCEED THE REVERSE BREAK- DOWN RATINGS OF THE DEVICE. (12) Treat all printed circuit boards with care. Do not burn or mutilate when making or breaking solder connections. Be extremely careful of the foil paths. Use solder-sucker type iron when removing components from the board. Do not over- heat diodes and transistors. (13) When replacing twisted-pair interconnecting wires, make certain that the replacement pairs are twisted in same manner. REMOVING MASTER UNIT FROM ITS WALL MOUNTING GROUND _ HINGE SCREW N / >< SUPPORT STRAP IM-303 INSTALLED IN IR-10 FIGURES (1) Disconnect: Power plug P4 from J4; and tuner's coax antenna lead from antenna terminal board. (Figure 8) (2) If the following optional equipment is included in system: (2.1) Phonograph and/or auxiliary Tape Player: Disconnect their shielded leads from J104 and/or J105. (2.2) 15-37 Speaker/Clock Timer: Disconnect the Protection circuit J31 from P31. (2.3) Background Music Amplifier: Disconnect the Blue and Black “Low Level Output” wires from the audio line (twisted-pair or shielded cable) that is feeding the background music amplifier. (3) REMOVING MASTER UNIT WITHOUT DIS- CONNECTING THE INTERCONNECTING WIRES AT THE TERMINAL BOARD. (Omit step (4) below) (3.1) (3.2) Disconnect the Terminal Board from Ampli- fier/Power Supply Module, i.e. P3 from J3. (3.3) Remove the four Terminal Board Phillips head mounting screws and lift terminal board, with Complete steps (1) through (2.3) above. —16— the interconnecting wires and cables intact, out of cabinet. Carefully stow the Terminal Board and attached wires in the rough-in housing. (4) REMOVING THE MASTER UNIT COM- PLETE WITH THE TERMINAL BOARD. (Omit step (3) above.) ( 4.1) Complete steps (1) through (2.3) above. (4.2) Remove the |/Р Speaker Controls’ flat three-wire ribbon type cables from their respective terminals. Each cable should be marked so that the Output (Silver) wires can be reconnected to their respective terminals. (4.3) Remove the Door Speaker wires and the Chime/Alarm wiring from their respective terminals. Label these wires so that they will be reconnected to their proper terminals. (4.4) The Terminal Board must be removed when the Station Selector Switches; Diodes; Resistors; Voltage Regulator Lights; or the P3/Wire assembly are to be repaired or replaced. (4.5) NOTE: WHEN THE TERMINAL BOARD IS NOT CONNECTED TO THE AMPLIFIER/POWER SUPPLY CHASSIS (P3 to J3) THE ENTERTAIN- (To Page 25) a 9, es dl о O Oa C303B L302 ESS NE < Е : 30 SN 2067, © — dEOEJ - C303C ——|l'avoc || vio a ; © | о T301B [es | os No — 2 | 1309 о "re O © 1301A— | =o Ode o/c DEF 21000 E A L303 R315 L304 и y | | _ N СРО ecu O, fe BD 37596-1C . 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СОРРЕК : CHIME/ © ALARM SILVER Nal-109L€ SILVER DOORS COMMON COMMON TERMINAL BOARD-TERMINAL SIDE LAYOUT/FOIL PATTERN FIELD REPLACEABLE PC MODULES {Original Production Units) FIGURE 9 —T8— H3|41NdNY Â 2 ! о © т ay ayvosd O O O O o) O 6.024 ~ ‚О “О ve zu - EC Zu nN N о = O 3 9 2 In [N © се 0% N alo sou) €) » 1@ : > É N ‚A sx 9 |e 8125 © O5 6189 1- сого le от : Бесы 4 D207 on SOrezy_ Heat Sink AMPLIFIER/POWER SUPPLY MODULE COMPONENT LOCATION 0203 Q204 Q205 AMPLIFIER/POWER SUPPLY FOIL PATTERN FIGURE 10 o | | | | > EP 21 :d) OPERATING VOLTAGES INPUT: 120 Vac, 60 Hz. AC TO BRIDGE Z201: 17 Vac, 60 Hz. — BRIDGE DC OUTPUT: Vee = 23 Vdc (Measure at J/P2-2) Regulated = 11.5 Vdc {Measure at J/P1-2) R103 VOLUME CONTROL: Minimum ; S102 SELECTOR SWITCH: AM {No Signal, Tune Off Station.) DEVICE PIN NUMBER : 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Z302 0.9 1.5 10.9 | 0.7 0 8 1.5 1.5 0.8 5.5 | 0.64 1 1 0 11 S1-2 SELECTOR SWITCH: FM (No Signal, Tune Off Station.) Regulated = 11.5 Vdc (Measure at J/P1-3) DEVICE PIN NUMBER 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Z301 2.1 2.1 2.1 0 24% | 5.4 5.9 6 6 10 i 5.3% 0 (+) Must be measured by Oxcilloscope or by meter with Hi-Z input. DEVICE ELEMENT FUNCTION SOURCE GATE 1 GATE 2 DRAIN Q301 R.F. Amplifier 1.7 1.85 3.6 8.6 EMITTER BASE COLLECTOR Q302 F.M. Mixer 0.25 0.9 10 0303 F.M. Oscillator 4.5 5.2 4.2 0201 |.C. Preamp 1.8 2.3 4.2 Q202 Key Click Suprsn. 0 0* 0 Q203 1st Audio Amp. 1.5 2.0 10.5 Q204 Audio Amp. 10 10.5 19.5 >— 0205 Audio Amp. 20 19.5 10.6 0206 Audio Driver 21.6 20 10.6 0207 NPN Audio Output 9.8 10.4 22.5 0208 PNP Audio Output 9.8 03 0 Q209 Voltage Regulator 11.5 12.0 23.0 — 0210 Muting 0 0** 0 Q401/0FF Door Relay 0 .049 20.1 Q401/ON 0 0.9 0.19 0402/0FF Key Click Suprsn. 0 О 0 Q402/ON 95 10 26 (*) Goes to 0.3 on meter (0.8 on scope) when “Key Click” suppression voltage is ON. (**) Goes to 0.7 when “Muting” is ON. (***) Measured with meter. Actual voltage measured on scope equal 0.8 volts maximum; discharging to zero in 150-200 milliseconds when depressing or releasing any TALK or LISTEN switch - CONTROL MODULE INTERCOM OPERATION INTERCOM CONTROL | Z401A Z401B Z401C Z401D OPERATING VOLTAGE | VOLTAGE | VOLTAGE | VOLTAGE | VOLTAGE | Q401/K401 D410 MODE POINT X TERM. 9 TERM. 4 TERM. 5 TERM. 10 DOOR RELAY AUDIO SWITCH OFF 17.5 OFF OFF OFF OFF OFF OFF DOOR LISTEN 9.9 13.5 OFF OFF OFF OFF ON DOOR TALK 5 OFF 11.3 OFF 11.3 ON OFF NP TALK 2 OFF OFF 13.5 13 OFF OFF 1/P LISTEN OFF OFF OFF OFF OFF OFF OFF (MASTER ONLY) MUTING VOLTAGE AT J2-5=1.4V; at Q210 Base=0.7V Co — —21— R3i8$ Q303 | 8.2K а с opt | 5.6p ve a | | (328 L303 4 ot | 10 pt £324 | Вр? a с R319 R320%$ 7:50 344 3036 OK 10K C3438 1561 | 5pt + C303J c330 | Г N A [A $ | [ caoso y с >} LIE | e Te |7 | | ( | | — NE — | 7 + | +309 = R329 = 2 155 — / | | | a SIA RADIO MODULE AMPLIFIER, EQ | CONTROL MODULE — | hmm FG | hy The, | thea | “70 R407 <3| 13< T 100 | *y* CT 44 == # 403 ? > С <5 | | 5 <] a — E caos © “Ta 2 4O1A(LISTEN TO DOOR) 22 -<7117€ | e {boire 2 D 7? Î 7 <9| | 9< D405. 4 406% | 72 [Pz < 0404 | # 4016 | QA Ral? | 2 402 | 2 4 4.7K | 2 401€ D408 ra | | (TALK 1 > | INSIDE) 0412 | | +22. 5\ ОС C404 | > J4 P4 sio Е | I6V AC = 0— 2 RÍO! FROM 105-N GRN г < Ор 424$ | | TRANSFORMER se R42 oe 10KS | e | 4103 — SZ | — | NOTE: O SCHEMATIC DIAGRAM DOOR RELAY 1. ALI | | | % W NUTONE MODEL IM-303 > au 3-WIRE RADIO/INTERCOM MASTER UNIT SPE FIGURE 11 A ee == ek e———— 500K PHONO S102 BLU. BLK Jos RIQ7 SELECTOR LOW LEVEL — И OUTPUT t1.5V. (REG.) INPUT GROUND mo MMON T . в y TONE SYSTEM OUTPUT GROUND common, — od R233 SIGNAL SV. 12K AM 11.5 FM 11s SV. | R FM SIGNAL ——л 23 4 56K - Dell r @210 |) CONTROL VOLUME Rail: | R212 T SE 3.9K —AAAA—QDCHIME & 47 R501 ALARM INPUT LISTEN EN OFF _ RADIO — INTERCOM TERMINAL BOARD TT] CONTROL LINE J4 1. 2. FIGURE 11 NOTE: \‹ ‹ < ET R214| -R213 AMPLIFIER/POWER [, C4 3.x 6-8% | | SUPPLY 10 . == | R215 | | ‘ o VA 504 50 50 99 Sis Г "Us “INPUT (COPPER) INSIDE PATIO SPKRS, - DOOR SPK”RS. LISTEN TALK LISTEN AL S103 $10 ПАН Е ВИ о R237 ALL RESISTORS: VALUES IN OHMS: 10% TOLERANCE: Ya WATT, UNLESS OTHERWISE SPECIFIED. ALL CAPACITOR VALUE IN MFD., UNLESS OTHERWISE SPECIFIED. cioz2 30 — —i—]]—a"— Ms RED [MASTER | TO VOLUME ; PROTECTION 200 CIRCUIT 250 | бе | COMPONENT IDENTIFICATION: 100 SERIES 200 SERIES 300 SERIES 400 SERIES 500 SERIES —22— CHASSIS MOUNTED COMPONENTS AMPLIFIER/POWER SUPPLY MODULE RADIO MODULE CONTROL MODULE TERMINAL BOARD INTERCOM CONTROL Z401A Z4018 ZAQIC Z401D LTAGE | VOLTAGE | VOLTAGE VOLTAGE VOLTAGE Q401 NOTE Diodes marked "c" Control Diodes marked "as" Audio Switching =1.4V; at (*) Voltage measured when switch is ELEMENT OFF depressed or released. On scope voltage will be approx. .8V de- B creasing to 0, in 150-200 milliseconds. TO AUDIO IN TONE CONTROL E TRA6 — — | C401 + | 500 —— “190 LEVEL SET — — —o PA o ret Amik —— —l—]——]—o——]— —]—— i— ———Éc———— — ——]—]]]——— MUTING = Te MUTING LINE (B) ыы z Je: = I/P TALK INPUT LINE | Ci © `` z CONTROL LINE ft 2 Y | cal INPUT x crounb | LU, LA a (La == [| < > 7? > <all 4.7K IP TALK | — all | | | al rw | | | нем 7 all € « ee | DOOR LINE ; Ce | + > | wel | у I R401 JS © 2 e 3.6K | © Lo _TERM | fe T — | il € ei ( [ [ [ ve Lis EN | = m 1 Po] | YELLOW | R20 RE 27 | CONTROL LINE | | | 1201 ; CONTROL MODULE = | 4 REGULATOR o REGULATED > У 22.5 У Q209 & IM с209 1* MUTING LINE (B) 7/7 GRO 470 AA, } T R235 R237 470 0210 2.2K 12v AMPLIFIER/POWER SUPPLY MODULE IM-303 SYSTEM INTERCOM SWIT( FIGURE 12 —23— si $2 INSIDE/PATIO DOOR OUTPUT SPKR ЗРК — SILVER о оо re ITO REMOTE SPKR TALKO TALKO | oa WITH Ico ' COMMON) a oa COMMON . VOLUMES | « o OUTPUT GROUND (CENTER) INPUT C1 R3 >— | | 200 = | <> COPPER QO = DOS | | NuTone W-3 I/P SPKR R2 O O | | | NO. 1 8.2K LISTEN 25 Q SPKR | RS | DOOR 5“ IN 15-35 01 _ | им CHIME, || 8” IN 15-38 AV QALAR M INPUT | | NO. 1 Pp | \ ! NuTone IW-3 St $2 | 2 1 INSIDE/PATIO DOOR ; I | OUTPUT SPKR > ‘ | ] SILYER . | TALK TALKO | 1 LISTEN IN | \ : 11 CENTER VOLUME | 2 OFF | es M INPUT 200 я 3 RADIO/INT | 30mid { | 53 } | IP SPKR 8.2K LISTEN 25 A SPKR | NO.2 DOOR а р: | SPKR > - Co 15-37 SPEAKER CONTROL € >> R502 | - e | 0509 „27 | Г — . 36V D508 Clock | < | | Pl Motor R21 R22 | D505 | | us 22K @22K — D504 я | Receptacie |— 120V | : 4 | In IR-7 1j 60 Hz | < | ; Y С DOOR | ! | ; Ш [ VAN X | \ VR21 VR22 | 1 1 & D501 | x. Earth | GE-DIA | | 1 Ground 1 [ \ A 1 + $y eur N \ | TERMINAL BOARD PPERLN A ! E 6 Mode | i Control BLK Le | In e а o | Protection 1 | Circuit dé Terminal Board Muting l BLK Switch | Y oo a a o J IS-37 CLOCK TIMER MUTING CONTROL NuTone W-2 6-37 PROTECTION CIRCUIT (Install in 1M-303) iM-303 CHASSIS GROUND ICOM SWITCHING & CONTROL FIGURE 12 vo RO © x L —»T0 ADDITIONAL DOOR SPKR —24— (OPTIONAL) DO NOT REMOVE HINGE AND PIN ASSY. FROM ROUGH-IN HOUSING (HINGE MAY UN и N MOVEABLE LEAF IN MASTER UNIT HOOKS OVER PIN IN STATIONARY LEAF ASSY. — —” BE ADJUSTED BY LOOSENING SCREW) IM-303 MASTER UNIT DETAIL OF LATER PRODUCTION HINGES FIGURE 13 (From Page 16) MENT PROGRAM AND INTERCOM SIGNALS WILL BE MUTED. THERE WILL BE NO POWER SUP- PLY GROUND CONNECTION FOR THE CONTROL MODULE. (46) TO OPERATE SET WHEN TERMINAL BOARD IS DISCONNECTED FROM THE CHAS- SIS, SHORT TERMINAL #4 TO TERMINAL #8 IN J3. THIS WILL PROVIDE A POWER SUPPLY GROUND FOR THE CONTROL MODULE, (5) ORIGINAL PRODUCTION UNITS: (Figure 8) (5.1) Remove screw holding the fixed leaf of each hinge to the rough-in housing. (5.2) Unfasten support strap at top of rough-in Housing and remove Master Unit. (6.1) Support the Master Unit and unfasten support strap at top of rough-in housing. (6.2) Lift Master Unit (with moveable leaf section of each hinge) up and away from the fixed leaf of each hinge. IN THE FIELD TERMINAL BOARD REPLACEMENT (1) Complete steps (3) and (3.1) under GEN- ERAL above. (Figure 8) (2) Disconnect the Terminal Board from Ampli- fier/Power Supply Module, i.e. P3 from J3. (3) Disconnect interconnecting wires as shown in paragraphs (4.2) and (4.3) above. (4) Remove the four Phillips head mounting screws (one in each corner) and lift Terminal Board out of unit. (5) Install new Terminal Board, making certain that the Station Selector Switches S501-S508 are aligned with their mounting holes in the front of chassis — behind the door. (6) Secure the Terminal Board in place with the four screws that were removed in step (4) above. (7.1) —25— (7) Reconnect the 1/P Speaker cables: The Silver (Output) wire of each cable must be connected to its proper Silver (Output) terminal. When required — for systems with more than eight 1/P Speakers — two or more Silver wires may be connected to a Silver terminal. (Figure 2) Copper (Input) wires should be divided among the Copper terminals so as to equalize the load. (7.2) THE CENTER (COMMON) WIRE OF EACH THREE-WIRE CABLE MUST BE CONNECTED TO AN INDIVIDUAL COMMON TERMINAL. (8) Reconnect the Door Speaker wires and the chime/alarm wires to their proper terminals. (9) Connect P3 to J3, i.e. to Amplifier/ Power Supply module. IN THE FIELD CONTROL MODULE REPLACEMENT (1) Some units (later production) have the mounting standoffs at front of module slightly twisted. These standoff tabs should be straight- ened (small pair of pliers may be used) before removing board, (2) Grasp Control Module gently but firmly and lift straight up — disconnecting J2 from P2. (3) Insert new module by fitting J2 to P2 and front mounting holes on chassis standoffs and press module gently but firmly in place. Do not press module down until it touches the chassis, but just far enough to make good contact between J2 and P2. (3.1) Later production units have a flexible plastic standoff around the two end pins (each side) of P2 to prevent pressing the module down too far. (4) When the Control Module is removed from the Master Unit, all of the 1/P Speakers in RADIO/ INTERCOM mode and the Master Unit speaker will continue to receive the entertainment program. (5) If the Master Unit 1/P LISTEN SWITCH S103 is activated (pressed-in), the 12Vdc from base of Q209/cathode of D210 will be connected through R237: contacts of S103; and D211 to the base of muting transistor Q210. This will result in silenc- ing of the entertainment program. (5.1) If the system includes an 18-37 Speaker/ Clock Timer and it is in the OFF; AUTO; or ALARM mode, the entertainment program will be muted. (6) With the Control Module removed from the chassis, i/P Speakers that are in LISTEN IN mode will be heard by the Master Unit Speaker and other 1/P Speakers that are in RADIO/INTERCOM mode, and chime and/or alarm signals will be heard by the Master Unit Speaker and by |/Р Speakers that are in RADIO/INTERCOM mode. (7) With the Control Module removed, all other intercom functions will be eliminated (excepting those noted in paragraphs (5) through (6) above). (8) If the Terminal Board is removed and the Control Module is removed, the entertainment program will be heard at the Master Unit Speaker, but there will be no Intercom Switching. IN THE FIELD TUNER MODULE REPLACEMENT (1) Tune radio dial to lowest frequency — completely closing tuning capacitor C303. (2) To eliminate the necessity of restringing the dial cord when new Tuner Module is installed: Using masking tape, secure the dial cord in-place around the pulley and secure the dial cord spring and connecting points on front of pulley. (3) Remove the Phillips head machine screw; the retaining cap and lock washer securing the pulley, and then gently slide the pulley off the tuning capacitor shaft. Tape the pulley with dial cord in-place to the chassis. (4) Remove the screw holding the tuner grounding strap at the front left corner of the module. (5) Remove the retaining screw and standoff at the right rear of the module. (6) If the standoff mounting tabs in front of board are twisted, straighten with a pair of pliers before lifting module: (7) Gently but firmiy lift the Tuner Module straight up — disconnecting J1 from P1. (8) Insert the new module by fitting J1 to P1 and the front mounting holes on the chassis standoffs and press gently but firmly in place. Do not press module down so-that it touches the Ampli- fier/Power Supply or the chassis. (8.1) Insert plastic standoff between right rear corner of module and chassis and secure in place with screw that was removed in step (5) above. (9) Secure the module grounding strap with the screw that was removed in step (4) above. (10) Make certain that ganged tuning capacitor C303 is completely closed and gently install pulley (with dial cord intact), securing in place with cap; lockwasher; and screw that were removed in step (3) above. | (11) Gently remove masking tape from pulley and check tuning dial tracking when TUNING KNOB is rotated. REMOVING TUNER/AMPLIFIER ASSEMBLY FROM MASTER UNIT HOUSING (1) This complete assembly must be removed from the housing when installing new pilot lights and when replacing or repairing the Amplifier/ Power Supply Module. (1.1) Because of the interconnecting wires and cables that are soldered to the Amplifier/Power Supply PC Board, it will generally be easier and quicker to replace or repair defective components on this board, than it is to replace the complete module. | (2). Remove the TUNING KNOB and ON-OFF/ MASTER SPEAKER VOLUME CONTROL Knob. Pull gently but firmly forward. (3) Disconnect Terminal Board P3 from Ampli- fier/Power Supply Module's J3. (4) If component to be repaired is on the Am- plifier/Power Supply Module and is under the Tuner Module (such as Voltage Regulator Q209) and/or under the Control Module: These modules may be removed by following instructions above. 7 ANTENNA LEAD-IN pra CONTROL MODULE 8 DOOR T/L! 8 | y S106 lo | | I/P T/L Cu \ ` | AN Nan, | PILOT LIGHTS =! FRONT OF CHASSIS FIGURE 14: TUNER/AMPLIFIER CHASSIS ASSEMBLY EXPLODED VIEW —27— (5) Remove Terminal Board by extracting the four Phillips head mounting screws and lifting board out of Master Unit. (6) Remove the eight, No. 8 Truss-Phillips-head screws that hold the chassis in the master unit. Note that one of these screws secures the P4 wiring assembly cable clamp. (7) By gently folding the chassis over and without removing interconnecting wires and cables, the components on the Amplifier/Power Supply and Heat Sink may be removed or repaired. REPLACING PILOT LIGHTS (1) Remove chassis from Master Unit as described in paragraphs (1) through (3) and (5) through (7) above. (2) Remove black guard from PROGRAM SE- LECTOR SWITCH S102. (3) Remove two hex-head screws holding dial lens to chassis. (4) Gently slide dial pointer from lens and lift lens and mounting bracket away from chassis. (5) Replace defective lamp. Use G.E. #259 or equivalent (NuTone Part No. 39330-000). Normal REPLACEMENT OF 1/P AND (1) Remove the rectangular switch knobs from the switches on the PC Board that, contains the defective switch. (2) Using solder-sucker iron, unsolder contacts of defective switch on its PC Board. (3) Remove the two screws holding the defective switch PC Board to chassis. Lift board away lamp has a dc resistance of 20 ohms when cold. Burnt out lamps read “Open.” (6) Lamps are connected in series, if one lamp is burnt out, all lamps will be OFF. (Because of the time involved, it may be desirable to replace all three lamps when the unit is disassembled for pilot lamp replacement.) (7) Slide lamps into wedge bases, making certain that wire contact on each side of bulb engages its base contact. (8) Reassemble unit by reversing steps (1) through (4) above. DOOR TALK LISTEN SWITCHES from chassis far enough to remove the defective switch from board. (4) Insert the new switch in PC Board and solder in place. (5) Insert PC Board in chassis and secure in place with the two screws that were removed in step (3) above. BENCH CHECKING THE MASTER UNIT (1) Connect power plug P4 to 16Vac (NuTone 105-N transformer). (2) Connect coax antenna cable from Tuner Module to test antenna. (3) For complete checkout of Master Unit, the Terminal Board must be connected to the Ampli- fier/Power Supply Board, i.e. P3 to J3. If unit was removed from its installation without the Terminal Board, use a spare. (3.1) If Terminal Board is not available, intercom operation can not be checked. To prevent muting of the entertainment program, short terminal #4 to terminal #8 in J3. If the terminals are not shorted, the Control Module may be removed to prevent muting. (4) If available, connect an 1S-38 or iS-35 In- side/Patio Speaker to the Terminal Board. Use IW-3 flat-3-wire cable and connect to proper terminals. (5) Connect a speaker to DOOR terminal and common. (Use 16 ohm speaker if available.) (6) Turn S101 ON and complete OPERATIONAL CHECKOUT procedure, pages 4 through 7. SYSTEM TROUBLESHOOTING (1) ENTIRE SYSTEM DEAD CHECK: Connections at P4/J4. 16Vac from secondary of 105-N transformer. Wiring between transformer and Master Unit. 120Vac supply to 105-N transformer. (2) PILOT LIGHTS OFF — ALL OTHER FUNCTIONS NORMAL CHECK: 16Vac at switch S101(B). Wiring at terminals v and w on Amplifier/power supply module and pilot light circuit. Pilot lamps PL101, PL102, PL103, R108 and R109. Lamps must be properly installed in bases. (3) NO FM — OTHER FUNCTIONS NORMAL CHECK: FM antenna must be installed and connected to Tuner Module. It must not be shorted at PC Board. Program Selector Switch S102. FM connections between Switch S102 and Amplifier/ Power Supply Module. Regulated +11.5Vdc at S102 and P1-3. J1 to P1 connections. Voltages on Z301 and Q303. (See Schematic Dia- gram and Voltage Chart, pages 20-22). FM tuner alignment. (4) NO AM — OTHER FUNCTIONS NORMAL CHECK: Antenna connections at terminal strip and on tuner module. Program Selector Switch S102 — AM connections between switch and Amplifier/Power Supply Module. Regulated +11.5Vdc at S102 and P1-2. J1 to P1 connections. Voltages on Z302. (See schematic diagram and Voltage Chart, pages 20-22). (5) CHECK: (6) CHECK: (7) CHECK: (8) CHECK: (9) CHECK: (10) CHECK: (11) CHECK: (12) CHECK: (13) CHECK: NO SOUND FROM MASTER UNIT SPEAKER — ALL REMOTE SPEAKERS OPERATING NORMALLY. Setting of Master Speaker Volume Control R101. S103, S104 and S106. Speaker and connections. NO SOUND FROM |/P SPEAKER(S) — MASTER UNIT SPEAKER OPERATING NORMALLY Station Selector Switches S501—S508, must be in Radio/ Intercom mode. Connection of 1/P Speaker wiring. Controls and connections at individual 1/P Speak- ers. Flat 3-wire cable between Master Unit Terminal Board. Connection at terminal #7 of J3/P3. 5103. Wiring between J3/P3 and Terminal Board. DISTORTION AT ALL SPEAKERS Setting of Master Unit Speaker Volume Control; Volume Control at every |/P Speaker and Setting of Volume All Speaker Control R103. (See paragraph 6 through 9, page 4). Amplifier for proper operation, voltages, etc. MASTER UNIT ON — SPEAKER : Program Selector Switch 5102. P3 from Terminal Board MUST be plugged into J3. + 22.5Vdc at terminal #2 J2/P2. Regulated + 11.5Vdc at terminal #2 or #3 of J1/P1. Operating voltages on transistors in Amplifier/Power Supply Module. Individual Volume Controls at Master Unit Speaker and at 1/P Speakers. All Speaker Volume Control R103. Level Set Control R211 on Amplifier/Power Supply Module. If system includes 1S-37 Speaker/Clock Timer, make certain that its Mode Switch is in ON position. (See page 6 RECORD PLAYER AND/OR TAPE PLAYER SILENT — ALL OTHER OPERATIONS NORMAL Program Selector Switch S102 — must be in correct position Shielded cable between record player and/or tape player and J104 and/or J105 — must be pushed all the way in at both ends. Cartridge in Record Player. Record or tape of known quality should be used when checking units. HUM FROM RECORD PLAYER — ALL OTHER OPERATIONS NORMAL Shielded cable between Record Player and Master Unit — outer shield must make good contact at both ends. Separate ground wire between Record Player Rough- in and ground connection in Master Unit Rough-in. Connections to cartridge in Record Player. NO MUTING DURING INTERCOM OPERATION Control Module connections J2/P2. Muting voltage at terminal #5 of J2/P2. J3/P3 connections. Control Line Point “X” voltage at terminal #8 of J2/P2. Muting Transistor Q210 base voltage. Operating voltages on Quad Amplifier Z401. 1/P Speaker(s) and NO SOUND FROM ANY BACKGROUND MUSIC SYSTEM, BACKGROUND MUSIC MUTED DURING INTERCOM OPERATION See Muting Circuit Modification in Addendum. See BACKGROUND MUSIC, page 7. MUTING ON — WHEN NO TALK OR LISTEN SWITCH IS BEING ACTIVATED Talk/Listen switches in Master Unit and in 1/Р Speaker Controls. Must not be stuck, should work freely. Ground connection at terminal “#1 of J2/ P2 and at terminals #4 and #8 of J3/P3. —29— (14) CHECK: (15) CHECK: (16) CHECK: (17) CHECK: (18) CHECK: (19) CHECK: (20) CHECK: (21) CHECK: (22) CHECK: (29) CHECK: Control Line Point “X” — resistance to ground should be very high when no Talk/Listen switch is activated. Quad Amplifier Z401 operating voltages. For collector to emitter short in Q202 and Q210. Shorts between INPUT (COPPER) and COMMON (CENTER) wires of the individual speaker cables. SIGNALS FROM CHIME AND/OR ALARM AND FROM SPEAKERS IN “LISTEN IN” MODE ARE TOO LOW Setting of Level Set Control R237. Lower volume of entertainment program, and increase the over-all volume of the system with System Volume Control R103. (See INTERCOM OPERATION, paragraphs (7.3) and (7.4), page 6.) NO INTERCOM SIGNALS FROM ANY SPEAKER OR FROM CHIME AND/OR ALARM — ALL OTHER FUNCTIONS NORMAL J3 to P3 connections. Intercom Input Transformer T201, D201, D202 and Q201. Check for “Key Click voltage on base of Q20?, and for emitter-coliector short in Q202. Q402-check operating voltages and for shorts between elements. DOOR SPEAKERS CANNOT RECEIVE NOR TRANS- MIT INTERCOM SIGNALS — ALL OTHER FUNC- TIONS NORMAL Wiring between DOOR and COMMON terminals and the Door Speaker. Should not be open or shorted. Connections at terminal #6 of J3/P3. Door wiring between DOOR terminal on Terminal Board and terminal #6 in P3. For shorted C501. Terminals #4, #6 and #7 of J2/P2, Door Relay K401. DOOR SPEAKER(S) CAN HEAR 1I/P AND MASTER UNIT SPEAKERS BUT CANNOT SEND SIGNALS TO 1/P AND MASTER UNIT SPEAKERS — ALL OTHER OPERATIONS NORMAL C403, D410, R418, Z401A. Control Line Point “X” voltage at terminal #8 of J2/P2. DOOR SPEAKER(S) CAN SEND SIGNALS TO, BUT CANNOT RECEIVE FROM I/P AND MASTER UNIT SPEAKERS — ALL OTHER OPERATIONS NORMAL Door Relay K401. Control! Line Point “X” voltage at terminal #8 of J2/P2. Z401B, R417, Q401. Connections at terminal #4 of J2/P2. SIGNALS CANNOT BE HEARD FROM 1/P SPEAK- ER IN “LISTEN IN” MODE — ALL OTHER OPER- ATIONS NORMAL Individual 1/P Speaker's volume control — turn to maximum. Check Paragraphs (7) to (7.4) page 5/6. HIGH PITCH SQUEAL Check for shorts between the SILVER (OUTPUT) wire and the COPPER (INPUT) wire in the ftat-3-wire cables between the Terminal Board and the individual 1/P Speakers. THE CENTER (COMMON) WIRE FROM EACH 1/P SPEAKER MUST BE CON- NECTED TO AN INDIVIDUAL COMMON TERMINAL. Shorts on Terminal Board or between wires in P3 wiring harness. LOW FREQUENCY FEEDBACK BETWEEN SPEAK- ERS DURING INTERCOM OPERATION. Volume setting of the offending speakers. Speakers must not be installed back-to-back on a common wall. Reduce volume of different speakers to determine acoustic coupling between individual speakers. SYSTEM PICKS UP RADIO INTERFERENCE. Make modifications as directed in Addendum. FM SQUELCH CONTROL FUNCTIONS POORLY ON WEAK FM STATION. Squelch Control Operation and Adjustment in Ad- dendum. ADDENDUM TO IM-303 Shielded Cable Audio Signal From S102 | | | | | | | | | P Muting Signal From "U" on Control Module 1/P2-5 < + | | Shielded Cable Audio Signal To C101/R103 | неон 8 = —o]— ——] o] —]]—]]—— 7 | | | | | | Muting | Transistor | — | Muting Signa! From 5103 or Clock/Timer 4 Protection Circuit LATER PRODUCTION (OR MODIFIED) MUTING CIRCUIT (Must be used in “Background Music” Systems) FIGURE A1 MUTING CIRCUIT MODIFICATION (1) Original production units, using Amplifier/ Power Supply PC Boards marked 37599-1B (foil side) and 37599-2B (component side), were constructed with. the muting circuit that is shown in the SYSTEM SCHEMATIC DIAGRAM. (1.1) When used in “Background Music” systems, units constructed in this manner will mute the entertainment program when the Master Unit Speaker and 1/P Speakers are operating in one of the intercom modes. (2) To prevent muting of the entertainment program during intercom operation, the muting circuit should be as shown in Figure A1 (2.1) When constructed in this manner, muting in systems incorporating “Background Music” will operate as shown in BACKGROUND MUSIC section under OPERATIONAL CHECKOUT. (Page 7) (3) To modify original production PC Boards, follow the instructions in Figure A2. DC POWER SUPPLY MODIFICATIONS (1) To aid in reducing diode rectifier switching noise, C207 and C208 — bypassing D203 and D205 respectively — were included in the original production units. Later production units will include C221 and (C222 — bypassing D204 and D206 respectively. (See SCHEMATIC DIAGRAM and Figure A3) (2) Original production units used a medium- power transistor (NuTone Part No. 36613-000) as the +11.5Vdc voltage regulator Q209. This transistor was secured to the main heat-sink by the small heat radiator (NuTone Part No. 36614-000). (2.1) To prevent instantaneous destruction (open or short) of the voltage regulator Q209, later production units will use a heavier-duty device, i.e. Motorola MJES20 (NuTone Part No. 36614-000). (3) To further protect against short circuiting; the 27-ohm, 2-watt, wire-wound resistor R239 (Nu- Tone Part No. 33028-270) has been added to limit the short circuit collector current of Q209. (3.1) R239 IS A 2-WATT RESISTOR. Being wire- wound, its physical size is approximately that of a one-watt carbon composition resistor. (4) SHORT CIRCUITING OF THE REGULATED +11.5VDC SUPPLY MAY DESTROY THE VOLT- AGE REGULATOR Q209. DO NOT SHORT TO GROUND WHEN MEASURING VOLTAGE OR WHEN ALIGNING TUNER. BE ESPECIALLY CARE- FUL AROUND THE +11.5VDC TERMINAL ON SELECTOR SWITCH S102. Use Insulated No. 22 Wire Between ws ху O O Отот, e 5 4 | Base and Collector Leads On Transistor and Base and Collector s02v | Terminals on PC Board K z 5 о © | 12° О ЧЕ | duvog > la ) E | H3I4!TdWY = > |» 3 Ir Instail on Heat Sink O of o e @ Q209 Voltage Regulator > 7 QU 5 O, О |» la CMF MJE 520 . . D s + о Od | Oo 102 > > O, 222 7 2 e o 1021 b © о о X Mica Insulating Washer N > I'd Use Heat Transfer Lubricant "oO o > с O! ) O © O Oya. 1 7 Remove Wire between X and X 43 6129 © а oczu — Instali R?239; 27 ohm; 2 pp QO oO + 2020) 2 watt; Wire Wound (33028-270) to sicy rr "59 = O 2020, ve в — Dh x Te 8 < + О О 1929 A] N 0129 8 6033 + 202 У 9 ea + — ey | оз « N\ —_— wed NM sozp ° стон) O tal o + = o ON 1 ~ N orn o a © |: Ola a xl x od N O TO Or 4169 > m0 O ———— © «| a O вога га К eme 9224 m о ] a 3 > INN > 8 — "oO Or z > o ; т > © lo giz Ogzz7u вого ; AL EIN + 3 _ ORIGINAL PRODUCTION al voz 6224 AMPLIFIER/POWER SUPPLY oz2u COMPONENT LAYOUT Remove R210 from PC Board. Install Shorting Wire in vacated R210 position (Between C206 and hi-side of R211). Break Foil Path between terminal * ¢’ and Wiper Contact of R211. install R210 between terminal ‘¢* and Wiper Contact of R211 (Foil Side). Install jumper between junction of R210/Wiper Contact of R211 and Collector of Q210. Add C221 and C222, Solder Leads at Points Shown. Insulate Capacitor jeads from PC Foil Paths. 7 ORIGINAL PRODUCTION 37599-18 © E AMPLIFIER/POWER SUPPLY / — FOIL PATTERN C222 C221 POWER SUPPLY & MUTING CIRCUIT MODIFICATION TO ORIGINAL PRODUCTION PC BOARDS | FIGURE A2 —31— SU APE EE I adr ere ete zz o O EE +22.5Vdc (Vcc) To | 510] PA ON/OFF | 7201 T—gs Te SE ZZ EEE ый Le | Г c207 | 9205 6 TL | | | C221 | | | | iéVac To Pilot Lights —— ese EERE, SEES we Ween) A SE AS o A ——— LATER PRODUCTION OR MODIFIED +22.5V AND REGULATED +11.5V DC SUPPLY R239 +|1.5Vde (Regulated) Q20% Voltage Regulator MJE 520 (36614) | 2.2K YELLOW Op | To S103 FIGURE A3 (5) Original production units used a 470 mf., 35 WVDC electrolytic capacitor for C209. (5.1) Later production units will use a 1,000 mf., 35 WVDC capacitor (NuTone Part No. 35091-1007) for C209. (6) The DC power supply on original production PC Boards may be modified so as to agree with Figure A3 by following the instructions with Figure A2. (Note: Some of the earlier production boards will include some of these power supply modifications.) NEW PC BOARDS (1) New PC Boards for later production units will be as shown in Figure A4. These boards will be marked 37599-1C (foil side) and 37599-2C (component side). (2) These new boards will include all of the modifications noted above and are interchange- able with original production boards. (3) Because of the time involved in removing the interconnecting wires and shielded audio cables, it may be simpler and quicker to modify the original boards as noted above, and as directed in Figure A2. R. F. INTERFERENCE (1) Such interference may originate with A.M. and/or F.M. broadcasting stations; and from radar transmitters, homing devices; diathermy equipment; etc. (2) When such interference is picked up on the DOOR line: | A .1 mf., 100 WVDC disc ceramic capacitor may be connected between DOOR and COMMON terminals on the Terminal Board. (This capacitor — C501, NuTone Part No. 35100-127 — is included in later production units, see Schematic Diagram.) Also, it may be necessary to connect a .1 mf., 100 WVDC capacitor across (between cathode and anode) Door Switching Diode D410 on the Control Module. (3) When the interference enters set through the INPUT (COOPER) line: Add a .1 mf., 100 WVDC ceramic capacitor between each pair of INPUT (COPPER) terminals and a COMMON (CENTER) terminal on the Terminal Board. (4) When interference enters set through the PHONO and/or TAPE INPUTS, a shorted RCA phono-plug may be inserted in J104 and/or J105. (5) If the interference is entering the system across components on the Amplifier/Power Supply Module, the following capacitors should be added: 100 pf., 100 WVDC, ceramic disc capacitor should be added between base and emitter of Q201; (NuTone Part No. 35100-131) 100 pf. between base and emitter of Q202; 100 pf. between base and emitter of Q203; 100 pf. between base and emitter of Q204; .1 mf. between emitter of Q204 and ground; .1 mf. from contact of ON/OFF SWITCH S101 and Ground. (6) In all cases, the capacitor leads should be as short as possible. The leads must not short the foil paths on the PC Boards. 02-66548 +11.5Vdc u w O КВ O O Отот, 6 2 d | (Regulated) e er I 00,7 w kz © LAN © О 2 Gr a О 0 OS @ |) 0209 | ayvos a 8 EIFIR PLL 2 |, xO |» | — O 0, O 9 09, O, юг? Po [© [2 |: LÍO " - ww _- +22.5Vdc @ | 0207 Tn 3 Torr HEE 9 @ | 0208 “o 119 + €) o > O or 602% 22 4022 42 HEAT SINK 2 o e +() O 2220 3 9 = 15 > o © в == oO ° Оса > De 5» м o 5 9122 = O 8020 9028 O Y e o » м? 3 91235 |+ | © Use Mica Insulating Washer 4 £020 “cod 107 god — соты and Heat Transfer Lubricant 2024 022» Between Transistors and Heat Sink. OUTPUT GROUND P2 FOIL PATTERN FIGURE A4: LATER PRODUCTION AMPLIFIER/POWER SUPPLY MODULE (7) Because of the many variations in the pick up of such R.F. interference, no definitive procedure, that will work in every case, can be pre- sented. In general, experiment and experience will lead to isolation of the source of entry for the unwanted signals, and the procedures listed above can be followed. SETTING OF F.M. SQUELCH CONTROL R315 (1) The Master Unit is supplied, from the factory, with Squelch Control R315 set at maximum position, i.e. with full squelch. (2) When sufficient (normally excess of 5 microvoits) F.M. broadcast band R.F. signal is fed to the input of the F.M. tuner, it will operate with full limiting and the setting of R315 will not effect the quantity nor quality of the recovered audio signal, and the signal-to-noise ratio will be in the order of 45 db. As the input signal increases, the signal- to-noise ratio will rise to the order of 70db. (See Figure A5) | (3) When there is sufficient RF signal and the squelch can be operated at maximum, the side- band response that is characteristic of limiter- discriminator F.M. operation will be eliminated. (Figure A6) The set will be quiet when tuned between stations, and tuning is as easy and un- ambiguous as in an AM receiver-without resorting to AFC. This eliminates AFC pull from a strong station when attempting to tune to a weak station. (4) When the RF input is below 5 microvolts, due to: distance from transmitter (fringe area); poor antenna; shielded RF area; etc., there will not be sufficient signal to drive the set to limiting, and it may be required that the squelch control be set to a lower point. (4.1) This may, improve listening satisfaction, but the receiver may be operating at a point where signal-to-noise ratio has deteriorated and the recovered audio is not acceptable. (5) In the field adjustment of the Squelch Con- trol R315 may be accomplished as follows: (5.1) Set ALL SPEAKER VOLUME CONTROL R103 and MASTER UNIT SPEAKER VOLUME CONTROL R101 for normal operation. (6.2) Set SQUELCH CONTROL R315 to minimum, i.e. no squelch. (5.3) Tune receiver to weakest F.M. station that the home owner will normally listen to. (5.4) If the weak station (paragraph (5.3) above) reception is acceptable, advance the SQUELCH CONTROL R315 until it interferes with reception of the station, then, back the control until reception is acceptable. (6) IN NORMAL OPERATION, WITH THE FM TUNER PROPERLY ALIGNED, THE RECOM- MENDED PROCEDURE IS TO IMPROVE THE O SIGNAL + NOISE a | SIGNAL + NOISE 10 (NO SQUELCH) SIGNAL + NOISE 20H (PARTIAL SQUELCH) [SN SIGNAL + NOISE © 30H (FULL SQUELCH) | u NOISE > so а -- > 2 sok f - 98 MHz DEVIATION = 75 kHz 60 rok goL_ 1 + dr gr 8 bg 2 5 5 2 2 2 5 0.1 | Lo) 100 IK 10 K INPUT —MICROVOLTS S + N AND N FOR NO SQUELCH; PARTIAL SQUELCH; AND FULL SQUELCH PLOTTED AGAINST RF INPUT FIGURE A5 8 0} | 20 (a) WITHOUT SQUELCH + = а. E 10) = o 5 E O” « À Lu X —10 ~ | ] | — -400 -200 O 200 400 TUNING ERROR — kHz S 10 | (b) WITH SQUELCH + => = © 30% MODULATION = 1000 Нг © > =_ } i | E 10H55} 5 y 250 kHz on | _-70«B D-70L --—-.- - Lo © TYPICAL TUNING CHARACTERISTIC: (a) WITHOUT SQUELCH; AND (b) WITH SQUELCH, SHOWING THE SUPPRESSION OF SIDE RESPONSE CHARACTERISTIC OF LIMITER — DISCRIMINATOR RECEIVERS FIGURE A6 R.F. SIGNAL INPUT. THIS MAY BE ACCOM- PLISHED BY INSTALLING AN OUTSIDE ANTEN- NA, AND IF REQUIRED, A DIRECTIONAL ARRAY: RAISING THE ANTENNA: OR BY CHANGING THE POSITION OF THE INSIDE ANTENNA THAT IS SUPPLIED WITH THE MASTER UNIT ROUGH-IN. REMEMBER, SUB-PAR OPERATION OF THE SQUELCH CIRCUIT IN A WELL ALIGNED MASTER UNIT IS DUE TO INSUFFICIENT INPUT SIGNAL. —34— All Capacitors: K (Kilo) = 1,000 REPLACEMENT PARTS LIST 1M-303 3-WIRE BUILT-IN RADIO/INTERCOM SYSTEM All Resistors: Value in ohms, 2 Watt Carbon Composition unless otherwise noted. m (micro) = 10* Value in farads, 500 WVDC Ceramic unless otherwise noted. M (Mega) = 1,000,000 p (pico) = 107: Schematic a: i gr sympa Part Description Schematic NuTone Description IM- C331, C335, M-303 MASTER UNIT C342 35100-127 1 mf., 100 WVDC (*) Used in IM-303-D Walnut Only C338 35091-108 100.mí., Electrolytic, 25 WVDC (**) Used in IM-303-L Golden Elm Only C339 35091-103 4.7 mf., Electrolytic, 256 WVDC CAPACITORS C301, C329 C302, C324, C330 C303A-J C304, C305, C307 C306, C340 C308 C309 C310 C311, C315 C312, C343 C344 C313, C317, C326, C332, C341 C314, C327 C316, C321, C333, C334, C336 C318 C319 C320, C337 C322, C323 C325 C328 13045-900* Complete Assembly 13047-900** Complete Assembly 41525-000 41533-000 37596-000 38637-003 41524-000 35100-161 35101-135 35092-000 31893-000 31894-000 41535-000 39327-000 39135-000 31872-000 39262-000 39335-000 35100-120 35100-140 35101-129 35100-138 35101-134 35100-125 35101-142 35100-139 35101-126 35100-141 35094-000 35100-156 35091-109 35101-141 35101-140 35090-000 Chassis Assembly Complete AM/FM TUNER MODULE Complete Assembly PC Board FM RF Shield Antenna Coax Lead-in Assy. (with Connectors) 180 pf. 7.5 pf. Variable, AM/FM Gang Tuning Tuning Shaft Bushing, Tuning Shaft Dial Cord Assembly Pulley, Tuning Capacitor Dial String Cap, Pulley, Tuning Capacitor Lock Washer, Pulley, Tuning Capacitor Spring, Pulley, Dial Cord Dial Pointer .001 mf. .02 mf., 50 WVDC 4.7 pf. 5,000 pf. 3.3 pf. 220 pf. (C311, Trap) 15 pf. .01 mf., 50 WVDC 1.2 pf. .05 mf. .33 mf. 2200 pf. 47 mf. Electrolytic, 16 WVDC 5.6 pf. 10 pf. 1-8 pf., Variable, Oscillator Hi-Frequency Trimmer, 100 WVDC/AC COILS AND TRANSFORMERS L301 L302 L303 L305 L306 L307, L308 L309 L310 T301A 7301B T302 CONNECTOR J1 DIODES D301 FILTERS CF301 CF302, CF303 LAMPS VR301 RESISTORS R301 R302 R303 R304 R305, R310, R322, R324 R306 R307, R311 30087-000 30086-000 30085-000 30089-000 30088-000 30073-000 31915-000 30092-000 30091-1071 30062-000 30090-000 30578-000 30093-000 30590-000 30591-000 30589-000 39339-101 36617-000 36088-000 36087-000 39438-000 33081-564 33081-224 33081-154 33081-391 33101-331 33101-333 33101-392 FM Ant. Primary FM Ant. Trap FM Ant. Secondary FM RF FM Oscillator Coil Form, for L301, L302, L303 Slug, Tuning Core, for L301, L302, L303 10.7 MHz. Quadrature De- tector Tuning 22 mH., RF Choke 10.7 MHz. Trap Coil 10.7 MHz. Choke AM Ant. Transformer AM Oscillator 10.7 MHz. FM IF Primary 10.7 MHz. FM IF Secondary 455 KHz. AM IF 5-Pin Receptacie Silicon Switching, 50 ma. DC; 75 PIV 1N914 Texas. Inst. 1N4148 10.7 MHz., FM IF, Ceramic Vernitron Piezoelectric Div. FM-4 (Preferred) Murata Corp. of America SFG-10.7MA 455 KHz., AM IF, Ceramic Murata Corp. of America SFB-455D Neon, 105-125Vdc/ac; Y watt; 1.9 ma. G.E. “Glow Lamp” #C2A-ET (NE-2H3T) or Equivalent 560K, Ya Watt 220K, Ya Watt 150K, Ya Watt 390, % Watt 330 33K 3.9K Schematic NuTone ati Schematic NuTone inti Symbol Part No. Description Symbol Part No. Description R308, R331 33101-102 1K C215 35100-162 27 pf. R309, R316 | . C216 35091-108 100 mf., 25 WVDC, Electrolytic R317 33101-47047 C218 35091-104 33 mf., 25 WVDC, Electrolytic R312 33101-272 2.7K С219 35091-105 470 mf., 25 WVDC, Electrolytic R313 33101-471 470 R314 33101-124 120K CONNECTORS R315 34043-000 500K, Potentiometer Trim, J3 39333-101 4-Pin End Black Connector FM Squelch (Left Light Blue) R318 33101-822 8.2K 39333-102 4-Pin End Block Connector R319. R320. (Right Dark Blue) R328 33101-103 10K J4 41541-000 Jack and Wire Assembly R321, R329 33101-182 1.8K Pi 39338-101 5-Pin Connector Post R823 33101-332 3.3K Assembly R325 33101-681 680 P2 39338-104 9-Pin Connector Post R326 33101-222 22K Assembly R327 33101-473 47K P4 41534-000 Plug and Wire Assembly R330 33101-101 100 DIODES D201, D202, Silicon Rectifier, 1 Amp. DC; TRANSISTORS D208, D209, 100 PIV, 1N4002 (D211 used 0301 36624-000 Dua! Gate FET. FM RF Ampli- D211 36549-000 in Later Production Only) fier, General Inst. Corp., D207 36589-000 Silicon, Temperature Tracking, MEM 615A, MEM 614 120 ma DC; 100 PIV, 1N3754 Q302 36578-000 NPN Epitaxial Planar Silicon, D210 36539-000 Silicon, Zener, 12 V, 1N4742A FM Mixer e es Motorola Inc., SPS-4448 SSEMO Y, INCUEES ely, : D204, D205, and D206: DC National Semiconductor, SM-43-049 Output 1.5A, PIV 100, General Inst. Corp. KPB02 Q302 36581-000 NPN Planar Silicon, FM Oscillator Texas Inst. SKA-4230 RESISTORS National Semiconductor, R201, R222 33101-270 27 SM-43-050 R202 33101-473 47K INTEGRATED CI ” UIT R203, R208 33101-334 330K ED CIRCUITS R204 33101-394 390K Z301 36623-000 FM IF, Detector _ RCA CA3089E R205 33101-154 150K S.G.S. ATES Co. TDA 1200 R206 33101-823 82K 2302 36622-000 AM Mixer, IF, Detector R207 33101-332 3.3K RCA CA3088E R209 33101-103 10K R210 33101-273 27K R211 34023-000 2.2M Potentiometer Trim, AMPLIFIER/POWER SUPPLY MODULE LEVEL SET 41529-000 Complete Assembly R212, R214 33101-392 EE Early Production niy 37599-000 PC Board R213 33101-682 6.8K R215 33101-821 820 (Early Production Only) CAPACITORS R216, R234 33101-563 56K C201, C203, C204, C213 35091-111 2.2 mf. 25 WVDC, Electrolytic| | 8217R219 + 33103-683 68K Metal Film C202, C214 35100-164 680 pf. R218 33103-153 15K Metal Film C205, C206, R220 33101-683 68K C220 35100-127 .1 mf., 100 WVDC R221 33103-822 8.2K Metal Film C207, C208, 01 mf., 50 WVDC (C221, C222 R223 33101-223 22K C221, C222 35100-139 in Later Production Only) R224 33101-562 5 6K C209, C217 35091-101 470 mf., 35 WVDC, Electrolytic (C209 Original Production) R225 33101-10010 C209 35091-107 1,000 mf., 35 WVDC, Electro- R226 93101-180 18 lytic (Later Production) R227 Not Used C210 35091-102 10 mf., 16 WVDC, Electrolytic R228, R229 33101-151 150 C211 35091-103 4.7 mf., 25 WVDC, Electrolytic R230 33101-470 47 C212 35068-106 2.2 mf., 50 WVDC, Electrolytic R231 33046-000 0.56, 2-Watt —36— Schematic NuTone Schematic NuTone Symbol Part No. Description Symbol Part No. Description R232 33048-000 0.82, 2-Watt LAMPS R233 33101-123 12K PL101, PL102, | Pilot. G. E. 4259 R236 33101-220 22 RESISTORS R237 33101-222 22K R101 34062-000 200 ohm Potentiometer. R239 33028-270 27, 2-Watt, Wire-Wound Master Unit Speaker ; Volume Control (Ganged R240 33101-472 4.7K (Later Production, ; ; Replaces R214 & R215) with S101 ON OFF) - 00K ohm, Potenti ter. TRANSFORMER R102 34060-000 Soa rash iometer T201 30593-000 Intercom Input R103 34061-000 100K ohm Potentiometer 32159-003 Mounting Bracket for T201 System VOLUME CONTROL TRANSISTORS R104 33101-822 8.2K o 020 NPN P s R105 33101-102 1K 201, 3, lanar Silicon: Low Q204 36580-000 Noise, Texas Inst. SKA-4220: R106 33101-333 33K Motorola Inc. SPS-1216; R107 33101-224 220K Nat. SemiCon. SMO-7329; R108, R109 33028-100 10, 2-Watt. Wire Wound 2N5088 Q202, Q210 36613-000 NPN Silicon, Texas Inst. TIS- 98, Motorola MPS A20 SWITCHES ON /OFF (6 y M Là qe S101 34062-000 / anged with Master Q205 36577-000 PNP Epitaxial Planar Silicon ; Texas Inst. SKA-4223: Unit VOLUME Control R101) 2N5086 S102 34622-000 DP4T, Slide, PROGRAM Q206 36603-000 Power, PNP Silicon: SELECTOR Motorola MPS-U55 39437-000 Guard, Black. for S102 38105-003 Mounting Bracket for Q206 S103, S104, DPDT, Slide, Momentary 40975-000 Q206/Bracket Assembly 5105, 5106 34631-000 TALK & LISTEN Q207 36614-000 | Power, NPN Silicon, Single 34628-000 Alternate Diffused: Motorola MJE 520 e KNOBS Q208 36619-000 Power, PNP Silicon, Single Diffused: Motorola MJE 371 39355-000* Master Speaker VOLUME Q209 36613-000 Voltage Regulator, NPN 39379-000** Master Speaker VOLUME Silicon, Texas Inst. TIS-98; - * Motorola MPS A20 39346 000" TUNING (Early Production Units) 39380-000** TUNING Q209 36614-000 Voltage Regulator, NPN 31878-000 Black Rectangular, Push- | Silicon, Single Diffused, button. TALK LISTEN Motorola MJE 520 (Later Production Units) 39360-000 Mica Washer, Output CONTROL MODULE Transistor Insulator (and Q209, Part No. 36614-000) 41531-0000 Complete Assembly 38500-000 Heat Sink 37597-000 PC Board 38574-000 Heat Sink {Use with Q209 Regulator, 36613-000 Only) CAPACITORS C401 35091-105 470 mf., 25 WVDC, Electroiytid CHASSIS MOUNTED COMPONENTS C402, C403 35091-108 100 mf., 25 WVDC, Electroiytic C404 35091-106 2.2 mf., 25 WVDC, Electrolytic 37605-000 PC Board, Door Talk/Listen C405 35091-11022 mf., 16 WVDC, Electrolytic 37606-000 PC Board, |/P Talk/Listen APACI DIODES CAPACITORS D401-D412 36617-000 Silicon Switching: C101 35100-165 ‚02 mf. = 20% | 40 ma PIV TE ща 4 C102 35068-104 30 mf., 30 WVDC Electrolytic ES TS C103 35101-143 220 pf. CONNECTOR CONNECTORS J2 39339-104 9-Pin Receptacle J101, J102, INTEGRATED CIRCUIT 3103 31451-003 Base, Pilot Lamps Z401 36625-000 Quad Amplifier (Comparator) J104, J105 41528-000 Bracket and Jack Assembly, Motorola MC3301P PHONO and TAPE inputs National Semiconductor 46388-000 Label, Phono-tape LM3900N, LM2900N Schematic NuTone 2... Schematic NuTone еле Symbol Part No. Description Symbol Part No. Description RELAYS 21018-000 Solderless Wire Connector K401 39334-000 SPDT, DOOR 46646-000 Service Manual American Zettler AZ530-08-1 46648-000 Homeowner's Manual 39381-000 Alternate 46650-000 Installation Instructions (Early) RESISTORS 46757-0000 Installation Instructions (Late) R408, R415 33101-105 1M 1001A-000* Cover, Control Door Assembly R416. R418 33101-332 3.3K 1002A-000 complete with Hinge, Spring R417 33101-472 4.7K 2402 33041-000 Resistor Pack, Includes R419- R424. All Resistors 18 Watt 2403 33042-000 Resistor Pack, Includes R401- 41542-000" Front Panel Assembly R407. All Resistors % Watt 41543-000** Front Panel Assembly TRANSISTORS Q401 3661 3-000 NPN Silicon 39415- H St Ch is S ri Motorola MPS A20 5-000 anger Strap, assis Suppo Texas Inst. T1S-98 31987-000 Hook, Hanger Strap Q402 36606-000 PNP Silicon, Motorola 36090-000 Speaker, 5-inch, 25-ohm, MPS-K71 (Yellow) Voice Coil MPS-A70 (B= 150-300) 41605-000 Hinge, Stationary Leaf and Pin Assembly (Fasten to Rough-in) INTERCOM SWITCHBOARD ASSEMBLY 38626-000 Hinge, Moveable leaf (Fasten CONNECTOR P3 RESISTORS R501 R502 DIODES D501, D508 D509 LAMPS VR501-VR504 SWITCHES S501, S508 41538-000 37601-0060 37603-000 33101-470 33101-270 36549-000 36611-000 39163-000 34618-000 34620-000 Complete Assembly PC Board 8-Pin Connector/ PC Board Assembly 47 27 Silicon Rectifier, 1 Amp. DC: 100 PIV, 1N4002 Silicon, Zener, 36 V, 1N5258 105-125 Vac/dc, G.E. "Glow Lamp” #C2A-T (NE-2H) or Equivalent DP3T, Non-Shorting Stackpole 55-93 Alternate GENERAL PARTS 45399-000 45407-0000 46757-000 46374-000 38614-000 39410-007 Label, FM Ant. Lead Label, Low Level Output Label, Instructions Label, Station Selector Switch Room Designator Bracket, Top Chassis Retaining Pin, Chassis Retaining IR-10 ROUGH-IN HOUSING C1 R1 R2 R3 Si s2 S3 13132-900 39096-000 46620-000 08525-000 40072-000 29911-000 40674-000 IC-31 REMOTE CONTROL 13655-900 38559-000 38571-000 35068-104 33101-102 33101-822 34063-000 39433-051 39401-051 39432-051 39435-051 39401-051 39432-051 38570-051 39401-051 39343-000 39344-000 30 mf., 30 WVDC, Electrolytic to Chassis) Complete Assembly Antenna Terminal Strip Caution Label Power Transformer, 16V, 15VA (NuTone 105-N} FM Antenna Assembly Transformer, 230Vac Primary (EXPORT ONLY) (X-302-N) Frame Assembly Complete Assembly Control Insert Bezel 1K 8.2K 200 ohm, Wire Wound Potentiometer, VOLUME CONTROL Contact Wire 1/P TALK Contact Contact Contact Wire DOOR TALK Contact Contact Contact Wire DOOR LISTEN Contact Pushbutton Knob, VOLUME CONTROL —38— Schematic Symbol NuTone Part No. Description 15-35 INSIDE 5-INCH SPEAKER WITH CONTROLS C1 R1 R2 R3 51 $2 53 13695-900 38527-000 36090-000 35068-104 33101-102 33101-822 34063-000 39433-051 39401-051 39432-051 39435-051 39401-051 39432-051 39436-051 39401-051 39343-000 39344-000 Complete Assembly Speaker Panel Speaker, 5-inch, 25-ohm Voice Coil 30 mf., 30 WVDC, Electrolytic 1K 8.2K 200 ohm, Wire Wound Potentiometer, VOLUME CONTROL Contact Wire 1/P TALK Contact Contact Contact Wire DOOR TALK Contact Contact Contact Wire DOOR LISTEN Contact Pushbutton Knob, VOLUME CONTROL 1S-37 INSIDE 5-INCH SPEAKER/ CLOCK TIMER WITH CONTROLS RI R2 R3 R3 51 $2 53 13700-900 41581-000 38609-000 39331-000 38610-000 46693-000 36090-000 41596-000 38624-000 35068-104 33101-102 33101-822 34063-000 39433-051 39401-051 39432-051 39435-051 39401-051 39432-051 38570-051 39401-051 39343-000 39344-000 Complete Assembly Front Panel Assembly Grille, Speaker Nameplate Lens Information Label Speaker, 5-inch, 25-ohm Voice Coil Control Assy (Intercom) Control Insert 30 mf., 30 WVDC, Electrolytic 1K 8.2K 200 ohm, Wire Wound Potentiometer VOLUME CONTROL Contact Wire I/P TALK Contact Contact Contact Wire DOOR TALK Contact Contact Contact Wire DOOR LISTEN Contact Pushbutton Knob, VOLUME CONTROL Schematic Symbol NuTone Part No. Description CLOCK TIMER PROTECTION CIRCUIT C31 D31 J31 P31 R31 R32 R33 VR31, VR32 R21/VR21, R22/VR22 41600-000 37614-000 35100-127 36549-000 39421-000 41601-000 33101-103 33101-223 33101-222 39163-000 36094-000 38611-000 32603-000 17351-000 39407-000 39405-000 41582-000 Complete Assembly PC Board ‚1 mf., 100 WVDC Silicon Rectifier, 1 Amp. DC: 100 PIV, 1N4002 Jack, 3-Pin Connector Plug, 3-Pin Connector Complete Assembly 10K 22K 2.2K Lamp, 105-125 Vac/dc, G.E. “Glow Lamp” No. C2A-T (NE-2H) or Equivalent CLOCK 8 CONTROL CIRCUIT Digital Clock Assembly Ground Strap Interlock Plug-Cord End Connector Knob, MODE SWITCH, TIME/ALARM SET Resistor 10K and Lamp Assembly, G.E. D-2A, 105-125 Vac, 2.6 ma, 1/3 watt Lamp/ Resistor Assembly Complete IS-38 INSIDE 8-INCH SPEAKER WITH CONTROLS C1 R1 R2 R3 51 $2 53 13705-900 13707-98900 38532-000 38533-000 36089-000 35068-104 33101-102 33101-822 34063-000 39433-051 39401-051 39432-051 39435-051 39401-051 39432-051 39436-051 39431-051 39343-000 39346-000 39380-000 Complete Assembiy 15-38D Complete Assembly 1S-38L Speaker Panel {S-38D Speaker Panel 15-38L Speaker, 8-inch, 25-ohm Voice Coil 30 mf., 30 WVDC, Electrolytic 1K 8.2K 200 ohm, Wire Wound Potentiometer VOLUME CONTROL Contact Wire 1/P TALK Contact Contact Contact Wire DOOR TALK Contact Contact Contact Wire DOOR LISTEN Contact Pushbutton Knob, VOLUME CONTROL, 15-380 Knob, VOLUME CONTROL, 1S-38L —39— NuTone Part No. Schematic Symbol Description NuTone Part No. Schematic Symbol Description IS-61 BUILT-IN DOOR SPEAKER 13747-900 “B' Unit Assembly, 8454-019 Panel 41327-000 Mounting Panel Assy (Includes Speaker) 38391-000 Panel, Speaker Mounting 36076-000 Speaker 3% Inch, 16-ohm, Weatherproof cone 15-63 SURFACE MOUNT DOOR SPEAKER 13751-900 Door Speaker Assembly 36076-000 Speaker 3% Inch, 16-ohm, Weatherproof cone 32268-000 Mounting Plate 38324-000 Nameplate 1S-64 SURFACE MOUNT DOOR SPEAKER WITH PUSHBUTTON 13753-2900 Door Speaker Assembly 36076-000 Speaker 312 Inch, 16-ohm. Weatherproof cone 32268-000 Mounting Plate 38359-000 Switch Insert 39280-000 Pushbutton Complete 1S-65 BUILT-IN DOOR SPEAKER 13755-900 36076-000 Door Speaker Assembly Speaker 3% Inch, 16-ohm, Weatherproof cone 1S-77 OUTSIDE WEATHERPROOF SPEAKER 13780-2900 Complete Assembly 38423-000 Outdoor Speaker Housing 36074-000 Speaker, Polyurethane, Weatherproof, 16-ohm, 20-watt Peak, Ceramic Magnet 41835-000 Hanger Bracket Assembly Complete 38424-000 Connecting Strap 39267-000 Bushing 39297-000 Spacer 38447-014 Mounting Bracket 41365-000 Hanger Bracket Assembly 38427-014 Hanger Bracket 38425-000 Grille 38599-000 Nameplate 31128-0000 Solderless Wire Connector IS-78 INSIDE METAL FRAME SPEAKER 13782-3800 Complete Assembly 32180-008 Panel 32181-032 Panel Back 36089-000 Speaker, 8-inch, 25-ohm Voice Coil 46665-000 Model Label 1S-79 OUTSIDE METAL FRAME SPEAKER 13784-900 Complete Assembly 32180-008 Panel 32181-032 Panel Back 36074-000 Speaker, Polyurethane, Weatherproof, 16-ohm, 20-watt Peak, Ceramic Magnet 46668-000 Mode! Label NuTone products are warranted to be free from defects in material and workmanship for 112) months from original! date of installation unless otherwise stated. Light bulbs, dial lights, record changer needles and batteries (with exception of those specifically designa- ted as rechargeable) are not warranted or guaranteed, in any manner for any length of time. During this warranty period, Nulone will repair or replace at Nulone's sole option, free af charge, any defective parts returned prepaid to our closest Aurhor- ized Service Center. Provide the model number of the product, original date of installation, and nature of difficulty being experienced. For the name of your nearest NuTone Authorized Service Center, residents of the contiguous United States call, toll free, 800-543-8687 in Ohio call, 800-582-2030. Residents of Alaska, Hawaii and all other locations outside the contiguous U.S, except Canada, write: Field Engineering Department, NuTone Division ot Scovill Mfg., Madison and Red Bank Roads, Cincinnati, Ohio 45227. Canadian residents contact: NuTone Electircal, Limited, 2 St. Lawrence Avenue, Toronto, Ontario M8Z — 578; 416-251-6580. Our warranty does not cover damage or failure caused by abuse, misuse, abnormal usage, faulty installation, improper maintenance or any repairs other than those provided by an Authorized NuTone Service Center, NUTONE WARRANTY There will be charges rendered for product repairs made after our warranty period has expired {12 months after original date of Installation! Specific parts of certain models have an extended war: renty period. These are specially noted in the current NuTone Catalog, NulTone is responsible for parts only during the remaining portions of the warranty period after the first 12 months. Labor isextra -- to be charged to the customer. Your Authorized Service Center can tell you what portions of your particular modet may have an extended warranty. THE FOREGOING WARRANTIES ARE IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IM- PLIED, FOR MERCHANTABILITY OR FITNESS, AND THERE ARE NO OBLIGATIONS OR LIABIL!I- TIES ON THE PART OF NUTONE OR SCOVILL MANUFACTURING COMPANY FOR CONSEQUEN- TIAL DAMAGES ARISING QUT OF OR IN CON- NECTION WITH THE USE OR PERFORMANCE OF THE PRODUCT OR OTHER INDIRECT DAMAGES WITH RESPECT TO LOSS OF USE, REVENUES OR PROFIT. THERE ARE NO WARRANTIES WHICH EXTEND BEYOND THE DESCRIPTION ON THE FACE HEREOF. THE WARRANTIES SETFORTH HEREIN MAY NOT BE EXTENDED OR ALTERED EXCEPT BY WRITTEN AMENDMENT. Nulone Housing Products MADISON & RED BANK ROADS e CINCINNATI, OHIO 45227 e PHONE 1-513-527-5415 Part No. 46646-000 Printed in U.S.A. 11/74

Nutone IM-303 Intercom

Key Features

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Frequently Answers and Questions

How many remote speakers can I connect to the IM-303?

Can I use the IM-303 with a background music amplifier?

What is the maximum distance I can run the speaker wires?

How do I mute the entertainment program during intercom operation?

Nutone IM-303 Intercom

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Frequently Answers and Questions

How many remote speakers can I connect to the IM-303?

Can I use the IM-303 with a background music amplifier?

What is the maximum distance I can run the speaker wires?

How do I mute the entertainment program during intercom operation?