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Page 1: ...www SteamPoweredRadio Com 1 fCMartin industries inc I I i INSTALLATlCN AND SERVICE MANUAL TR 66A SCA TRANSISTORIZED MULTIPLEX RECEIVER ...
Page 2: ... SPECIFICATIONS SPECIAL FEATURES 1 2 4 GENERAL DESCRIPTION S INSTALLATION PROCEDURE 6 FIELD ADJUSTMENTS TROUBLESHOOTING 7 TRANSISTOR AND DIODE COMPLEMENT SCHEMATICS 11 12 il CE n EIEI C Jx uu il llk PIH 1 OJ f l Ul U U LA_ll u t _S McMcinin i 1U Fid inc omaha ncnrusku ...
Page 3: ...adcast and Audio Products are warranted to be free from defects in workmanship FOREVER At our discretion we will exchange or repair any defective unit or components at any time without charge Material and components are guaranteed for a period of ninety days from the date of original purchase Return authorization should be obtained and transportation char es must be prepaid on equipment returned f...
Page 4: ...ess coax connector Less than 0 5 at 1007 modulation 400 Hz 41 42 65 or 67 kHz at 6 kHz deviation other frequencies special order Must specify frequency when ordering 20 Inj 10 1 Inj 5 microvolt 45 db quieting 5 microvolt 30 db quieting 7 5 kHz at 3 db points 150 microsecond standard 75 microsecond on special request Main to SCA SCA to SCA Stereo to SCA 55 db 55 db 55 db 30 8 000 Hz 2 db at 150 mic...
Page 5: ...r switch volume control power ON OFF AC convenience outlet unswitched Antenna connector Antenna B switch Fuse holder Mike preamp input 4 pin Jones plug Adjustable automatic main channel muting 105 120V AC 50 60 Hz fused at 0 5 amp normally 5 watts with LT lOA 15 watts with LT 20 22 watts 11 wide x 4 1 2 high x 8 3 4 overall depth gray cover and brushed chassis 7 lbs Neon assembly 3 ...
Page 6: ...channel and sub channel limiter amplifiers RF shielding meets FCC requirements Unit is supplied with an RF solderless connector both male and female for 72 ohm coax There is a front panel switch for MN main and MX sub channel This switch simplifies servicing and enables a customer to switch to the main channel for special announcements such as historical events or local distress notices A cover nu...
Page 7: ...quelch voltage amplifier and a one stage audio amplifier The dual gate squelch board and audio amplifier consists of a main and subchannel gate which requires both main and subchannel squelch voltage for operation Positive squelch will occur in case of main channel failure The audio amplifier has an unbalanced low impedance output Two plug in audio modules are available to transform the TR 66A int...
Page 8: ...f multipath cross talk reception and only proper antenna installation can eliminate this This condition is most c011111on in large metropolitan areas and mountainous country High gain antennas normally have the best directional pattern and although signal strengcb may be high at a given location it may still be necessary to use this type to eliminate multipath The antenna should be o iented for a ...
Page 9: ...round 3 0 VDC scale 3 Turn the oscillator slug counterclockwise out as far as it will go 4 Insert the proper crystal into the crystal socket Crystal frequency Operate Frequency 10o7 mHz 2 S Slowly turn the oscillator slug clockwise in until the ne ative voltage rises abr ptly indi cating oscillation Continue clockwise until the voltage drops 1 10 to 2 10 of a volt below the peak to insure positive...
Page 10: ...d in a fringe area and no voltage is present at test point C test point B should be used for alignment In very weak signal areas the voltage may be positive and the receiver should be tuned for minimum positive or a negative going voltage For steps 5 6 8 9 10 11 and 12 it is PREFERABLE to USE a VTVM This completes the oscillator and RF align ent On units with screw driver adjusted oscillator slug ...
Page 11: ... adjustment of volume be made with the amplifier Main Channel Automatic Muting 1 The bottom plate must be removed for adjus ting the main channel mute z The tuner is shipped from the factory with the mute adjusted for approximately 5 microvolts 3 The main channel mute control is located on the mute and audio printed circuit board under the chassis blue control 4 The main channel mute should be adj...
Page 12: ...TED TO AN OUTSIDE ANTENNA IF THE ANTENNA B SWITCH IS IN THE ON POSITION AS THIS WILL SHORT CIRCUIT B DAMAGING THE POWER SUPPLY AND WII L MAKE THE RECEIVER COMPLETELY INOPERATIVE THE SWITCH MUST ALSO BE IN THE OFF POSITION WHEN CONNECTING THE 1R 66A TO A SIGNAL GENER ATOR OR ANY TEST EQUIPMENT f ...
Page 13: ... the base of Q 4 If the signal is present Q 4 is defective b If no signal is present at the base of Q 4 connect an oscilloscope to the collector of Q 3 If a signal is present at this point check capacitor C 28 for an open or short circuit condition c If no signal is present at the collector of Q 3 conn ect an oscilloscope to the base of Q 3 If a signal is present at the base of Q 3 Q 3 is defectiv...
Page 14: ...ot check the IC CA 3011 c If a square wave is present at terminal No 5 of IC then connect the scope to the base terminal of Q 2 A sawtooth signal should be present at this point If not check C 11 and C 12 for a short circuit d If an audio signal is present at the base of Q 3 connect the oscilloscope to the collector of Q 3 This should be a high amplified audio signal with some residual RF If not c...
Page 15: ...mHz AMPLIFIER AND DEMODULATION BOARD PART NO 012013 CA 2018A CA 3011 40245 SE 4010 SE 4002 SE 4001 SE 4002 SE 4001 IN 51 IN 51 IN 3604 IN 3604 IN 51 IN 51 IN 3604 IN 3604 IN 3604 c Wide Band Amplifier Wide Band Amplifi er and Limiter IF Amplifier Pulse Amplifier Wide Band Audio Amplifier Emitter Follower Output AGC Voltage Doubling Diodes AGC Voltage Doubling Diodes IF Limiter IF Limiter Squelch V...
Page 16: ...ain Channel Switch Q 2 201049 SE 4002 Sub Channel Switch Q 3 201019 40232 Mute Switch Q 4 201049 SE 4002 or SE 4001 Audio Amplifier Q 5 201049 SE 4002 or SE 4001 Audio Amplifier POWER SUPPLY PART NO 012014 Q 1 201046 40310 Regulator D 1 210008 R8D8 Rectifier D 2 210008 R8D8 Rectifier D 3 210008 R8D8 Rectifier D 4 210008 R8D8 Rectifier D 5 220007 13V Zener Reference Diode 13 ...
Page 17: ...ANT S0 1 5J IOMM RF CH 1 20 V C H I AHO II O lN SW I 1 0 7 CRYSTM l ll T 11 A C 0 5AW Pl 1 0 7MHI 1 AMP UIIIITO T POW SUHI Y RE 8 1372 ca ul 64k AUDIOIN 4 1 MIC 8 1 2V sue CH SUB Fl Tt i t A ir I _ sue y 82K I V 38V 10 7V OU l G T C 60ul 12 V 6411 001 ICM am o JM OMAHA NEBR NON 8 1372 MUTE AHO I AUOIO AUOIO GAIN IOK AUOIO OU TPIJT ...
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Page 20: ... _ I I I I QI I 40310 _ _ __ i 13 V D C I W C4 400 I I 40V I I I I D5 13V ZENER I L_____________ __J ADJUST TO DRAW 8 TO 10 Ma MCMartin _Industries Inc OMAHA NEBR TITLE SCHEMATIC POWER SUPPLY TR 66A RECEIVER owN BY J M Hansen DATE 7 27 67 ENG K 7 vi SCALE NONE APP O BY OWG A 1584 I i j I li I I I I ...
