Elenco Electronics AM-550CK Assembly And Instruction Manual Download

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SCHEMATIC DIAGRAM

ELENCO

150 Carpenter Avenue ● Wheeling, IL 60090

(847) 541-3800 ● Website: www.elenco.com ● e-mail: [email protected]

AM-550CK_REV-A_010416.qxp 1/19/16 9:05 AM Page 36

Summary of Contents for AM-550CK

Page 1: ...S 2 DIODES Assembly and Instruction Manual Copyright 2016 2011 by ELENCO Electronics Inc All rights reserved REV A Revised 2016 753008 No part of this book shall be reproduced by any means electronic...

Page 2: ...3 Identifying Capacitor Values Qty Symbol Value Description Part r 1 C1 Variable Tuning 211677 r 1 C15 0 001mF Discap 102 231036 r 2 C3 C10 0 01mF Discap 103 241031 r 5 C2 C5 C7 C8 C9 0 02mF or 0 022m...

Page 3: ...bly Coil Color dot Earphone Jack with Nut Knob dial Radio Stand COILS MISCELLANEOUS Label Screw M1 8 x 7mm Screw M2 5 x 4mm Nut M1 8 Speaker Pad 50kW Potentiometer Switch with Nut and Washer Knob pot...

Page 4: ...egative lead is indicated on the packaging by a stripe with minus signs and possibly arrowheads Also the negative lead of a radial electrolytic is shorter than the positive one Polarity marking BAND 1...

Page 5: ...alignment procedure is provided to peak the performance of the receiver and maximize the Dual Audio Superhet 550C s reception capabilities The Dual Audio Superhet 550C can best be understood by analy...

Page 6: ...industry but it is now being replaced by lead free solder for health reasons This kit contains lead free solder which contains 99 3 tin 0 7 copper and has a rosin flux core Lead free solder is differe...

Page 7: ...Your meter should again be reading a high resistance Typical results read approximately 1MW to infinity Refer to parts list and find a PNP transistor refer to Figure B page 8 for locating the Emitter...

Page 8: ...istors are working as Class A amplifiers for very small levels of power to the speaker but they slide toward Class B operation at larger power levels Transistor Q4 is a Class A amplifier that drives t...

Page 9: ...gray red brown gold D2 1N4148 Diode see Figure E R16 1kW Resistor brown black red gold TP10 Test Point Pin see Figure F R15 100W Resistor brown black brown gold Electrolytics have a polarity marking...

Page 10: ...solder side of the PC board Step 1 Step 3 Step 2 PC Board solder side J1 Earphone Jack with Nut see Figure G Speaker Speaker Pad 4 Wire see Figures H I Battery Holder 3 Screws M1 8 x 7mm 3 Nuts M1 8...

Page 11: ...r shorts or parts inserted incorrectly Check C14 to see if it s leaky or inserted backwards If you get a reading higher than 150kW check for open copper or bad solder connections on resistors R13 and...

Page 12: ...The voltage should be between 0 5 and 0 8V higher than the voltage at TP8 All silicon transistors biased for conduction will have approximately 0 7V from the base to the emitter If your circuit fails...

Page 13: ...voltage at TP8 here V3 __________ volts Once again parallel resistor R13 with resistor R4 as shown in Figure 6 The voltage at TP8 should also drop to a lower voltage Record the new reading at TP8 her...

Page 14: ...d minimum voltage output Set your VOM to read an AC voltage of 1 volt at the output of your Audio Amplifier Slowly increase the output of the generator until the VOM reads 1 volt AC Leave the audio at...

Page 15: ...ncy from the generator until the waveform on the oscilloscope drops to 0 7 of its original reading 1 4 Vpp or 2 8 divisions Use the oscilloscope probe to check TP6 to make sure the input voltage did n...

Page 16: ...imum power output should be greater than 200 milliwatts MAXIMUM POWER OUTPUT Connect the generator and oscilloscope as shown in Figure 8 Set the generator at a frequency of 1kHz turn the power ON and...

Page 17: ...Figure 12b if a capacitor is placed between pins 1 and 8 The gain can be set to any value from 20 to 200 if a resistor is placed in series with the capacitor The amplifier in our kit with a gain of 5...

Page 18: ...tch Notch marking STATIC MEASUREMENTS IC AUDIO AMPLIFIER SW2 on the down IC position RESISTANCE TEST You have completed wiring the IC Audio Amplifier We shall proceed in testing this circuit You will...

Page 19: ...gure 16 Make sure that the battery or a 9 volt power supply if available is properly connected and turn the power ON The voltage at TP8 should be between 4 to 5 volts If you get this reading go on to...

Page 20: ...TP10 10mF Generator GND TP10 Connect the oscilloscope and audio generator to your circuit as shown in Figure 18 Set the audio generator for a frequency of 1kHz and minimum voltage output Set the osci...

Page 21: ...nnect the generator and oscilloscope as shown in Figure 18 Set the generator at a frequency of 1kHz turn the power ON and adjust the generator output until the peaks of the sinewave at TP8 are clipped...

Page 22: ...o at the volume control as shown in Figure 19 The purpose of the automatic gain control AGC circuit is to maintain a constant audio level at the detector regardless of the strength of the incoming sig...

Page 23: ...the VOM is adjusted to read 9 volts DC and turn the power ON The voltmeter should read approximately 1 5 volts DC If your reading varies more than 0 5 volts from this value turn the power OFF and che...

Page 24: ...clockwise position Slowly adjust the amplitude of the RF generator output until you hear the 1kHz on the speaker If this test fails turn the power OFF and check C11 R12 volume control D1 and TP3 SYSTE...

Page 25: ...in Figure 23 Both IF amplifiers are tuned to a frequency of 455kHz and only need to be aligned once when the radio is assembled These amplifiers provide the majority of the gain and selectivity needed...

Page 26: ...ulation and minimum amplitude output Set the oscilloscope vertical sensitivity at 1 volt division The scope probe must have an input capacitance of less than 50pF or it will detune transformer T3 Turn...

Page 27: ...23 BANDWIDTH TEST FIRST IF AMPLIFIER The operation of the first IF amplifier is the same as for the second IF amplifier with one important difference The gain of the first IF amplifier decreases after...

Page 28: ...Figure 27 This short prevents the AGC from lowering the gain of the first IF ampifier Set the RF generator to 455kHz no modulation and minimum amplitude output Set the oscilloscope for a vertical sen...

Page 29: ...he selectivity of the antenna Q factor is high the image will be reduced sufficiently The oscillator circuit must also change when the radio is tuned in order to remain 455kHz above the tuning of the...

Page 30: ...white to the hole marked 1 4 Wire Type Antenna Solder the 4 colored wires to the PC board r Wire A green to the hole marked 3 r Wire B red and black twisted together to the hole marked 2 r Wire C whi...

Page 31: ...from oscillating Set the VOM to read 2 volts DC accurately and turn the power ON The DC voltage at TP1 should be 1 6 volts If the voltage in your circuit differs by more than 0 5 volts leave the power...

Page 32: ...he power ON Increase the amplitude of the RF signal until the oscilloscope registers 0 5Vpp Align transformers T3 T2 and T1 for the maximum AC reading on the oscilloscope Decrease the amplitude of the...

Page 33: ...na coil may have to be on the end of the ferrite rod as shown in Figure 33 Change the frequency of the RF generator to 1400kHz and adjust C1 until a 400Hz tone can be heard coming from the speaker Car...

Page 34: ...the station is at its loudest and reduce the volume if necessary Retune the radio for another weak station and repeat this procedure until there is no more improvement noticed on the weakest possible...

Page 35: ...result is a speaker less efficient and distorted To eliminate the low frequency cancellation a speaker is placed inside an enclosure Now the front sound waves are prevented from traveling to the back...

Page 36: ...SCHEMATIC DIAGRAM ELENCO 150 Carpenter Avenue Wheeling IL 60090 847 541 3800 Website www elenco com e mail elenco elenco com...

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