Elenco Electronics AM-550TK Instruction Manual Page 1

AM RADIO KITMODELSUPERHET AM-550TK7 TRANSISTORSAssembly and Instruction ManualCopyright © 2010, 1999 by ELENCO®All rights reserved. Revised

-9-ASSEMBLY INSTRUCTIONSFigure FMount the jack with the nut from the foil side of thePC board (terminal #1 on the GND pad of the PCboard). Be sure to

STATIC MEASUREMENTSRESISTANCE TEST-10-+DC AmpsAmps COM V/ΩΩAmpsCOMV/ΩGNDR15You have completed wiring the Audio Amplifier. We shall proceed in testing

-11-Adjust your VOM to read 9 volts and connect it to testpoint 8 (TP8) as shown in Figure 5.Make sure that the battery, or a 9 volt power supply (ifa

-12-VAmps COM V/Ω1MΩFigure 6BatteryGNDR15Adjust your VOM to read 9 volts DC. Connect thepositive lead of the VOM to TP6 and the negative leadto any g

If an oscilloscope is not available, skip the following test and go directly to Section 2.-13-Output AdjustVAmps COM V/Ω10μFGeneratorFigure 7BatteryGN

-14-OscilloscopeGeneratorProbeOutput Adjust10μFFigure 8GNDR15GNDR15Connect the oscilloscope and generator to your circuitas shown in Figure 8.Set the

Measure the maximum voltage peak to peak whenclipping first occurs and record that value here:Vclp = _______ Vpp.Using a wire short out resistor R17 a

The purpose of the detector is to change the amplitudemodulated IF signal back to an audio signal. This isaccomplished by a process called detection

-17-ASSEMBLY INSTRUCTIONS - DETECTORSTATIC MEASUREMENTSC6 - 100μF Lytic(see Figure B)R5 - 27kΩ Resistor(red-violet-orange-gold)T1 - IF Coil (yellow)TP

-18-Figure 13Generator.02μFVAmps COM V/ΩGNDR15GNDR15DYNAMIC MEASUREMENTSTurn the power OFF and connect the VOM and RFgenerator as shown in Figure 13.

PARTS LISTIf you are a student, and any parts are missing or damaged, please see instructor or bookstore.If you purchased this AM radio kit from a dis

-19-SECTION 3Figure 15.707452kHz 458kHz455kHzTP4 - Test Point Pin(see Figure A)T2 - IF Coil(White)Q3 - 2N3904 Transistor NPN(see Figure C)R10 - 470Ω R

-20-Figure 16VAmps COM V/ΩGNDR10STATIC MEASUREMENTSWith the power OFF, connect the negative lead of yourVOM to any ground and the positive lead to the

-21-SECTION 4Figure 17AR4 - 1MΩ Resistor(brown-black-green-gold)TP2 - Test Point Pin(see Figure A)Q2 - 2N3904 Transistor NPN(see Figure C)R6 - 1kΩ Res

-22-Figure 18OutputAdjustOscilloscope.02μFClip LeadGNDR6GNDR6GeneratorSTATIC MEASUREMENTSWith the power turned OFF, reconnect your VOM to testpoint 3

-23-SECTION 5In a superheterodyne type receiver the radio wave at theantenna is amplified and then mixed with the localoscillator to produce the inter

-24-ASSEMBLY INSTRUCTIONS - ANTENNA, MIXER AND OSCILLATORL1 - Antenna with Holders(see Figures I & J)C2 - .02μF or .022μF Discap(marked 203 or 223

Insert the cardboard antenna shim between theferrite core and the antenna coil. This willtemporarily hold the coil in place.Figure LPunch out one ant

-26-Figure 20Figure 19OscilloscopeVAmps COM V/ΩClip LeadGNDR2GNDR2STATIC MEASUREMENTSWith the power turned OFF, connect the VOM to yourcircuit as show

-27-Figure 21.02μFOutputAdjustOscilloscopeGeneratorClip LeadGNDR2GNDR6ProbeAntenna TrimmerOscillator TrimmerAntenna Trimmer3 Leads 4 LeadsFigure 22FIN

-28-Figure 23Figure 24WaxHolderCoilWire LoopClose toAntennaProbeOutputAdjustOscilloscopeGeneratorGNDR6With the power turned OFF, connect test equipmen

-2-PARTS IDENTIFICATIONRESISTORS CAPACITORS SEMICONDUCTORSResistorDiscapElectrolyticRadialTuningDiodeTransistorAntenna AssemblyCoilColor DotTest PinEa

-29-DC VoltagesThe voltage readings below should be used in troubleshooting the AM radio.Q1 B 1.5V Q5 B 8.3VE 1.0V E 9.0VC 8.9V C 5.8VQ2 B 1.4V

-30-SCHEMATIC DIAGRAM

ELENCO®150 Carpenter AvenueWheeling, IL 60090(847) 541-3800Website: www.elenco.come-mail: [email protected]

-3-IDENTIFYING RESISTOR VALUESUse the following information as a guide in properly identifying the value of resistors.BANDSMETRIC UNITS AND CONVERSION

-4-INTRODUCTIONMIXERLOCALOSCILLATORFIRSTIF AMPLIFIERSECONDIF AMPLIFIERDETECTORAUDIOAMPLIFIERAGCFigure 1SpeakerAntennaSection 1Section 2Section 3Sectio

-5-CONSTRUCTIONSolderSoldering IronFoilSolderSoldering IronFoilComponent LeadSoldering IronCircuit BoardFoilRosinSoldering iron positionedincorrectly.

-6-TEST A TEST B TEST C TEST DTEST E TEST FLow ResistanceNPNEBCHigh ResistanceNPNEBCLow ResistancePNPEBCHigh ResistanceDiodeLow ResistanceDiodeHigh Re

Theory of Operation - The purpose of the AudioAmplifier is to increase the audio power to a levelsufficient to drive an 8 ohm speaker. To do this, DC

-8-ASSEMBLY INSTRUCTIONS - AUDIO AMPLIFIERWe will begin by installing resistor R14. Identify the resistor by its color code and install as shown on pa