THE QRP LABS QCX-40

Building The QCX LABS 40M 5W CW Tranceiver

The QRP-LABS Web Page
and
The Assembly Manual

Bags of parts to be inventoried.

Notice SMT components installed at factory.

~~ Pages 6 & 7 Step 2~~

Inventory all the parts.

The kit has been inventoried.There were 2 100uh molded inductors missing .

Each part was placed in #1 coin envelopes and labeled. To make
it easier to find when needed. There were several extra components

OK! LETS GET TO IT
You Should use the manual as it shows the parts placement
NOTICE! the color coding in the manual
The part(s) being installed are "RED"
Those parts already installed are "GRAY"
The parts that have not been installed are "WHITE"

~~ Pages 49 thru 54 Step 3.55 ~~

Because I had a lot of issues with this "BOOGER T1" on the
QCX 20, I decided to do it first and get it over with.(G)

Wind and Install transformer T1

(L) drawing of T1 (R) schematic of T1

Windings needed on T1 on 40 meters


Views of T1 wound using 28 ga wire...did not like result


rewound T1 using 34 ga wire I think it looks better
at least I can count the turns. A pain with wire that thin.

~~ Page 14, Step 3.2~~

Install the 28 pin IC socket for IC2

BE SURE to observe the proper orientation.

~~ Page 15, Step 3.3~~

Install the DIP intergrated circuits IC3

Install the DIP intergrated circuits IC5-10

BE SURE to observe the proper orientation.

~~ Page 16, Step 3.4~~

Install all 16 of the 100nF (0.1uf,"104") capacitors
C2,C3,C6,C12,C29,C32,C34,C35,C36,C39,C40,C41,C48,C49,C50 and C52

~~ Page 16, Step 3.5~~

Install all 5 of the 470nF ("474") capacitors
C11,C43,C44,C45 and C46

~~ Page 17, Step 3.6~~

Install all 5 of the 1nF ("102") capacitors
C14,C16,C18,C23 and C33

~~ Page 17, Step 3.7~~

Install the 4 of the 10nF ("103") capacitors
C4,C7,C10 and C42

~~ Page 18, Step 3.8~~

Install 2 47nF ("473") capacitors C9 and C13

~~ Page 18, Step 3.9~~

Install the 39nF ("393") capacitors C17

~~ Page 19, Step 3.10~~

Install 2.2nF ("222") capacitors C19 and C20

~~ Page 19, Step 3.11~~

Install the 33nF ("333") and the 3.3nF ("332") capacitors
C15 and C53 they are in parallel and make up 36nf

~~ Page 20, Step 3.12~~

Install the capacitors C25 and C26
from the 40M Low Pass Filter Kit
they are 680pf ("681")

~~Page 21, Step 3.13~~

Install the capacitors C27 and C28
from the 40M Low Pass Filter Kit
they are 270pf ("271")

~~ Page 22, Step 3.14 ~~

Install 56pf ("560") capacitor
C30 the 40M band dependent capacitor

~~ Page 23, Step 3.15 ~~

install Capacitor C5 39pf ("390") and C8 not used on 40M

~~ Page 23, Step 3.16 ~~

Install capacitor C31 1uf ("105")

~~ Page 24, Step 3.17 ~~

Install the 1N4148 Diodes
D1,D2,D4 and D5. Observe orientation

~~ Page 25, Step 3.18 ~~

Install the 1N5819 Diode
D3. Observe orientation

~~ Page 26, Step 3.19 ~~

Install the 20Mhz Crystal

~~ Page 27, Step 3.20 ~~

Install the 27Mhz Crystal

~~ Page 27, Step 3.21 ~~

Install all 15 of the 10K resisters
R1,R2,R7,R10,R14,R34,R39,R40,R46,R49,R50,R51,R52,R57 and R58

~~ Page 28, Step 3.22~~

Install all 12 of the 1K resisters
R3,R4,R25,R26,R37,R42,R45,R53,R54,R55,R62and R63

~~ Page 29, Step 3.23 ~~

Install all 11 of the 3.3K resisters
R12,R13,R15,R16,R19,R20,R22,R23,R24,R44,R56 and R59

~~ Page 29, Step 3.24 ~~

Install all 4 of the 100 ohm resisters
R5,R6,R8 and R9

~~ Page 30, Step 3.25 ~~

Install the 3 120K ohm resisters
R38,R43 and R60

~~ Page 30, Step 3.26 ~~

Install the 2 33K ohm resisters
R28 and R29

~~ Page 31, Step 3.27 ~~

Install the 2 47k ohm resisters
R30 and R31

~~ Page 31,Step 3.28 ~~

Install the 2 36k ohm resisters
R32 and R33

~~ Page 32, Step 3.29 ~~

Install the 270 ohm resister at R48

~~ Page 32, Step 3.30 ~~

Install the 470 ohm resister at R41

~~ Page 33, Step 3.31 ~~

Install the 3.9K ohm resister at R61

~~ Page 33, Step 3.32 ~~

Install the 4.3K ohm resister at R18

~~ Page 34, Step 3.33 ~~

Install the 5.1K ohm resister at R11

~~ Page34, Step 3.34 ~~

Install the 7.5K ohm resister at R21

~~ Page 35, Step 3.35 ~~

Install the 750K ohm resister at R48

~~ Page 35, Step 3.36 ~~

Install 100K ohm LCD Contract trimmer resister at R47

~~ Page 36, Step 3.37 ~~

Install 500 ohm multi-turn trimmer potentiometer at R27

Observe orientation

~~ Page 36, Step 3.38 ~~

Install 50k ohm multi-turn trimmer potentiometer at R17and R24

Observe orientation ~~ Page 37, Step 3.39 ~~

Install 2 100uh inductors at L5 and L6
After consulting with the designer any inductor could be used
for L5 & L6 parts wer obtained from my parts box

~~ Page 38, Step 3.40 ~~

Install 6 10uf electrolytic capacitors C21,C22,C24,C37,C38 and C51
capacitors are polarised,Observe orientation
>

~~ Page 39, Step 3.41 ~~

Install 220uf (may be supply at 470uf) electrolytic capacitor at C47
capacitor is polarised, Observe orientation
because of component height install horizontally

~~ Page 40,Step 3.42 ~~

Install 30pf Trimmer capacitor C1

~~ Page 40, Step 3.43 ~~

Install Transistor Q6 MSP751

~~ Page 41, Step 3.44 ~~

Install Transistors BS170 at Q1,Q2,Q3, Q4,Q5 and Q7

~~ Page 41,Step 3.45 ~~

Install 2 X 3 pin in-circuit programing header
Since I'm not a programmer the header will not be used
I did not install it

~~ Page 42, Step 3.46 ~~

Install 4 pin GPS header
Since I'm not using the GPS option.
I did not install the header.

~~ Page 42, Step 3.47 ~~

Install 3 pin DVM/RF detector header
Since the DVM/RF detector header will not be used
I did not install it.

~~ Page 43, Step 3.48 ~~

Install the 3 1-pin TEST POINTS

~~ Page 43,Step 3.49 ~~

Install power connector
I do not like terminal blocks for power connections
I use Anderson Power Poles whenever possible

~~ Page 44, Step 3.50 ~~

Install 7805 voltage regulator IC11

~~ Page 44, Step 3.51 ~~

Install pin headers for the LCD module

~~ Page 45, Step 3.52 ~~

Wind and Install toroid L4 for 40m
requires 16 turns on a T37-2 toroid core

~~ Page 47, Step 3.53 ~~

Wind and Install toroid L2 for 40m
requires 24 turns on a T37-6 toroid core

~~ Page 48, Step 3.54 ~~

Wind and Install toroids L1 and L3 for 40m
requires 21 turns on T37-6 toroid cores

~~ Page 55, Step 3.56 ~~

Install RF output BNC connector

~~ Page 56, Step 3.57 ~~

Install 3.5mm stereo connectors

(L) headpones (R) key/paddles

~~ Page 56, Step 3.58 ~~

Install buttons S2 and S3 (left and right buttons)

~~ Page 57, Step 3.59 ~~

Install rotary encoder

~~ Page 57, Step 3.60 ~~

Install Micro switch

~~ Page 58, Step 3.61 ~~

Install gain control potentiometer R36

~~ page 59, Step 3.62 ~~

Install four 12mm hex spacers at the LCD corners

~~ Page 59, Step 3.63 ~~

Install four 12mm hex spacers at the PCB corners

~~ Page 60, Step 3.64 ~~

Install the two knobs

~~ Page 60, Step 3.65, Step 3.66 and 3.67 ~~

Install 16-pin female connector on LCD module,Install microcontroller
Install LCD and four screws to bolt on LCD module

This QCX 40M TRANSCEIVER IS COMPLETE

~~ Step 3.70 ~~

Alignment and Calibration Procedure Next

#1 Adjust Contrast.

#2 Select band that transceiver was built for In this case its forty meters (14mhz)

#3 Peak BPF (band pass filter)

#4 Adjust I-Q balance

#5 Adjust R27 for minimum

#6 Adjustment of 90 degree audio phase shift

#7 Phase LO, adjust R24 for minimum

#8 Phase HI,adjust R17 for minimum

#9 Following the adjustments of the trimmers the transceiver is ready for use.

QCX-40 TEST

Completed test 8.41 vdc mesured on Dummy load approx 4 watts output to a dipole.
Worked AE5II on 7.055 mhz on 12 FEB 2018 a FB QSO.W5LA monitored exchange.

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