MFJ 8100K Instruction Manual Download Page 39

Page: 39 / 40

Circuit Component Index

Part Number

Value/Description

Step No.

MFJ Part No.

C1 Air-variable,

tuning

4-7

204-5050

C2 .1

2-17

200-2017

C3 47

1.9

205-0021

C4 .1

1-7

200-2017

5-30 pF trimmer

1-10

204-0013

C6 33

2-7

200-2016

C7 .01

2-2

200-2015

C8 .01

2-13

200-2015

C9 .0033

polystyrene

3-11

201-0008

C10 .1

3-13

200-2017

C11 .1

3-10

200-2017

C12

22 uF electrolytic

3-5

203-0013

C13

100 uF electrolytic

3-3

203-0015

C14

10 uF electrolytic

3-4

203-0012

C15 .1

3-9

200-2017

C16 75

2-20

200-1011

C17 .0033

polystyrene

2-12

201-0008

C18

1 uF electrolytic

2-3

203-0006

C19

470 uF electrolytic

3-2

203-0004

C21 .01

2-15

200-2015

C28 .01

2-16

200-2015

CR1 LED

3-19

320-0001

IC1

LM386 audio amp

3-1, 3-20

311-0386

L1 10

1-2

401-0102

L2 3.3

1-3

401-0045

L3 1

1-4

401-0037

L4 .47

1-5

401-0015

T-52-2 toroid, 8T

4-10

403-1003

Q1 J310

FET

2-8

305-6310

Q2 J310

FET

2-9

305-6310

Q3 J310

FET

2-10

305-6310

10K pot, regeneration

4-6

162-4100-1

250 ohm pot, volume

4-5

162-2250-1

R3 10K

2-4

100-4100

R4 10K

1-6

100-4100

R5 10K

2-1

100-4100

R6 1K

2-5

100-3100

R7 1M

2-11

100-6100

R8 10K

2-14

100-4100

R9 1K

3-12

100-3100

R11 22

ohms

3-7

100-1220

R12 15

ohms

3-8

100-1150

R13 2.2K

1-8

100-3220

R17 10

ohms

2-6

100-1100

R19

10K timmer, RF gain

2-19

130-4100

R20

100K trimmer, regeneration

2-18

130-5100

J1 Antenna

connector

6-14

06-0003

Stereo 1/8" jack

4-2

601-4010

Stereo 1/8" jack

4-3

601-4010

SW1

5-position rotary switch

4-8

500-0024

SW2

DC on-off push-button switch

4-4

504-0022

Summary of Contents for 8100K

Page 1: ......

Page 2: ...UCTION 19 28 Construction Phase 1 steps 1 1 through 1 10 19 Construction Phase 2 steps 2 1 through 2 20 20 Construction Phase 3 steps 3 1 through 3 20 22 Construction Phase 4 steps 4 1 through 4 14 23...

Page 3: ...ent that you may return the entire kit UNASSEMBLED for credit or refund If you have never built an electronics kit before PLEASE study this book carefully before unpacking the small parts Once you hav...

Page 4: ...or over a decade these magical whistling squawking glowing boxes were the norm for home listening as well as for the first generation of radio hams Receiver design evolved swiftly The superheterodyne...

Page 5: ...e ready please explore the technical explanation of your receiver in Introduction No 2 In the meantime you can peek at the schematic diagram and picture the receiver in three basic sections A Detector...

Page 6: ...w level audio signal which is boosted to comfortable listening level by the LM386 integrated circuit amplifier The RF amplifier serves two purposes It boosts the RF signals from the antenna to the det...

Page 7: ...ls of simplicity and economy To meet our goals we chose to refine the regenerative concept as much as possible using contemporary design concepts and component characteristics Our first goal was to ta...

Page 8: ...combination of simple inductors For example the total inductance for Band A is L1 L2 L3 L4 L5 The inductance for Band E is only L5 And so forth Air variable C1 uses its 50 pF range and mechanical vern...

Page 9: ......

Page 10: ...er s performance we ve provided a separate section on its use In brief it controls receiver sensitivity and adjusts between AM broadcasts and CW SSB VOLUME R2 This potentiometer performs the normal fu...

Page 11: ...st NOT be pushed all the way in or it will short out the audio ANTENNA CONNECTOR J1 This binding post permits easy hookup of any wire or a banana plug may be inserted in its end 10 to 20 feet of ordin...

Page 12: ...gins to squeal oscillate Always use the LEAST amount of regeneration necessary for good reception of a given signal As a rule the best reception of AM shortwave broadcast signals occurs just BEFORE fu...

Page 13: ...which permits easier tuning These are all LSB lower sideband signals Think to yourself for LOWER sideband tune DOWN for UPPER sideband tune UP In practice this means that you would approach the LSB si...

Page 14: ...ective solder connection resulting form using too little heat The joint looks like a ball and is not shiny CW Continuous Wave refers to Morse Code signals DC direct current example battery voltage in...

Page 15: ...ed carefully through the use of a regeneration control RF Radio Frequency Energy in contrast to audio or DC RTTY Radio Teletype SSB Single Sideband a method of voice transmission which eliminates the...

Page 16: ...R6 R9 1 2 2K ohm red red red R13 4 10K ohm brown black orange R3 R4 R5 R8 1 1M ohm brown black green R7 INDUCTORS 1 10 H molded brown black black silver L1 1 3 3 H molded orange orange gold silver L2...

Page 17: ...nd SW1 3 3 8 steel washers for controls and SW1 2 Instrument knobs for controls 1 Pointer knob for band switch 1 Larger 1 25 knob for tuning 1 Pointer assembly for tuning capacitor 8 Pan head phillips...

Page 18: ......

Page 19: ...n with other parts If you watch out for just these 5 pitfalls you will build your receiver right the first time and start enjoying its worldwide receiving capabilities right away Your receiver kit is...

Page 20: ...which they resemble Correct selection and installation of the inductors is essential to correct tuning of your receiver If you mix them up what you hear will not correspond to the tuning dial If you...

Page 21: ...ted and we ve made sure that this receiver will tune correctly Construction Phase 2 Steps 2 1 through 2 20 The parts in Phase 2 are the heart of your receiver working together with the tuning circuit...

Page 22: ...2 9 Install transistor Q2 per 2 8a above 2 10 Install transistor Q3 per 2 8a above 2 11 Install R7 1M ohm brown black green 2 12 Install C17 0033 F body marking 332K 2 13 Install C8 01 F marked 103M...

Page 23: ...arefully Be sure not to let the solder tip touch two pins at the same time which would cause unwanted solder bridges 3 2a In step 2 3 above you installed the first of the 5 electrolytic capacitors use...

Page 24: ...f the bulb The anode side is nearest the 5 position bandswitch SW1 3 19b Install LED CR1 per 3 19a and the following Insert the LED with anode side toward SW1 Slide it into holes as far as it will go...

Page 25: ......

Page 26: ...ring points Touch up any questionable solder point by reheating the connection with a very clean soldering iron tip 4 14 Use the double sided adhesive strip to secure the 9 volt battery bracket in the...

Page 27: ...ead to Step 5 10 regarding adjustment of trimmer R20 In order to do that adjustment you first need to experience exactly what regeneration sounds like which we ll do in 5 8 5 8 With the controls set p...

Page 28: ...For now keep the screw tips flush with the top of the spacers 6 3 Attach the four self adhesive bumper feet to the bottom of the cabinet in a symmetrical pattern 6 4 Slip the PC board into the cabinet...

Page 29: ...pointer stripes of the knobs before tightening 6 13 Recheck the LED for best positioning through the front panel 6 14 Attach the rear antenna binding post The split washer goes against the inside of...

Page 30: ...u have determined whether adjusting C5 moved WWV closer to or further away from the desired point on the dial Repeat adjustment of C5 and the Main Tuning until the dial pointer is on the correct frequ...

Page 31: ...ntrol is learned through experience It controls the sensitivity of the receiver and distinguishes between AM broadcasts and CW SSB 3 The tuning ranges are set up so that you can expect to find somethi...

Page 32: ...g or pipe as well as wire The wire can be bare or insulated It could be something not intended to be an antenna such as a gutter fence flagpole or metal roof In fact radio hams and serious SWL s have...

Page 33: ...utility or communications speaker AUTHOR S NOTE I have fully tested this use of a second identical LM386 IC circuit with speaker and can recommend it highly to all who can t confine all this listenin...

Page 34: ...4 35 MHz you can hear strong CW and SSB voice signals from around the world throughout the day and well into the evening This is the most active and crowded of the international ham radio bands You al...

Page 35: ...iew all construction steps carefully Let somebody else go over your work and the steps Following are minor problems which are easy to solve One band seems identical to an adjacent band Check the solde...

Page 36: ...ur exact difficulty as clearly as possible You will be best helped if you have your unit manual and all information on your station handy so you can answer any questions the technicians may ask You ca...

Page 37: ...hanging C3 or any inductance affects the tuning range of ALL the bands Author s Hint To save you time as well as wear and tear on the PC board here s what my own curiosity showed reducing C3 can easil...

Page 38: ...er acquainted with radio communications and electronics as a hobby as a possible profession or both Among the hundreds of publications available we are pleased to recommend the following as especially...

Page 39: ...2 16 200 2015 CR1 LED 3 19 320 0001 IC1 LM386 audio amp 3 1 3 20 311 0386 L1 10 uH 1 2 401 0102 L2 3 3 uH 1 3 401 0045 L3 1 uH 1 4 401 0037 L4 47 uH 1 5 401 0015 L5 T 52 2 toroid 8T 4 10 403 1003 Q1...

Page 40: ......

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MFJ 8100K, Instruction Manual, Page: 39 / 40

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