CW Monitor Introduction

(go directly to build notes)

CW Monitor Schematic

CW Monitorschematic

(go directly to build notes)

CW Monitor Bill of Materials

Stage Bill of Materials

(resistor images and color codes courtesy of WIlfried, DL5SWB's R-Color Code program)

CheckCountComponentMarkingCategory
21 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W
1100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W
2100k 1/4W 1%brn-blk-blk-orng-brn brn-blk-blk-orng-brn1/4W
610K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W
11R 1/4W 1% (1R)brn-blk-blk-silver-brn brn-blk-blk-silver-brn1/4W
12k2 1/4W 1% (2.2K)red-red-blk-brn-brn red-red-blk-brn-brn1/4W
2330 1/4W 1%ora-ora-blk-blk-brn ora-ora-blk-blk-brn1/4W
147K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W
34K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
1JRC27F/012 relayJRC27F/012 JRC27F/01212V relay
41N41481N4148 1N4148Axial
11N41481N4148 1N4148Axial
510 nF (.01uF)103 103Ceramic
9100 nF104 104Ceramic
2UA741 OpAmpLM741 LM741DIP-8
11 uF/25Vdc Electrolytic
1100 uF/25Vdc Electrolytic
1misc hookup wireHookup
33.5mm stereo jack - PCB mount (rt-angle) Jack-RA
1SPDT 2 positionSPDT
1BC546 NPN Transistor TO-92
2BC556 PNP Transistor TO-92
110K (Y103)Y103Trimpot

CW Monitor Summary Build Notes

CW Monitor Detailed Build Notes

Top of the Board

CW Monitor Top View

Install Diodes, Resistors, Capacitors

(see above)

CheckDesignationComponentMarkingCategoryOrientationNotes
D7-11N41481N4148 1N4148Axial 
D7-21N41481N4148 1N4148Axial 
D7-31N41481N4148 1N4148Axial 
D7-41N41481N4148 1N4148Axial 
D7-51N41481N4148 1N4148Axial 
(reloc)
R7-11R 1/4W 1% (1R)brn-blk-blk-silver-brn brn-blk-blk-silver-brn1/4W 
R7-2100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W 
R7-3330 1/4W 1%ora-ora-blk-blk-brn ora-ora-blk-blk-brn1/4W 
R7-4330 1/4W 1%ora-ora-blk-blk-brn ora-ora-blk-blk-brn1/4W 
R7-51 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W 
R7-61 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W 
R7-72k2 1/4W 1% (2.2K)red-red-blk-brn-brn red-red-blk-brn-brn1/4W 
R7-104K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
R7-84K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
R7-94K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
R7-1110K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
R7-1210K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
R7-1310K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
R7-1410K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
R7-1510K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
R7-1610K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
R7-1747K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W 
R7-18100k 1/4W 1%brn-blk-blk-orng-brn brn-blk-blk-orng-brn1/4W 
R7-19100k 1/4W 1%brn-blk-blk-orng-brn brn-blk-blk-orng-brn1/4W 
C7-110 nF (.01uF)103 103Ceramic 
C7-210 nF (.01uF)103 103Ceramic 
C7-310 nF (.01uF)103 103Ceramic 
C7-410 nF (.01uF)103 103Ceramic 
C7-510 nF (.01uF)103 103Ceramic 
C7-10100 nF104 104Ceramic 
C7-11100 nF104 104Ceramic 
C7-12100 nF104 104Ceramic 
C7-13100 nF104 104Ceramic 
C7-14100 nF104 104Ceramic 
C7-6100 nF104 104Ceramic 
C7-7100 nF104 104Ceramic 
C7-8100 nF104 104Ceramic 
C7-9100 nF104 104Ceramic 
C7-151 uF/25Vdc Electrolytic 
C7-16100 uF/25Vdc Electrolytic 

Install Ics and Transistors

Note: there are tw0 BC556 and one BC546 transistors. Be sure to mount the correct value in the correct location and to orient the body of the transistor as indicated on the silkscreen.

Note the orientation and electrostatic sensitivity of the two OpAmp Ics.

Install Ics and Transistors photo
CheckDesignationComponentMarkingCategoryOrientationNotes
U7-1UA741 OpAmpLM741 LM741DIP-8 
Take ESD precautions
U7-2UA741 OpAmpLM741 LM741DIP-8 
Take ESD precautions
Q7-1BC546 NPN Transistor TO-92 
Q7-2BC556 PNP Transistor TO-92 
Q7-3BC556 PNP Transistor TO-92 

Install Trimmer Pot and Connectors

Install Trimmer Pot and Connectors photo
CheckDesignationComponentMarkingCategoryOrientationNotes
K7-1JRC27F/012 relayJRC27F/012 JRC27F/01212V relay 
P7-13.5mm stereo jack - PCB mount (rt-angle) Jack-RA 
P7-23.5mm stereo jack - PCB mount (rt-angle) Jack-RA 
P7-33.5mm stereo jack - PCB mount (rt-angle) Jack-RA 
R7-2010K (Y103)Y103Trimpot 

Install Wire W4

Install wire W4 to the bottom of the board as indicated below.

Install Wire W4 photo
CheckDesignationComponentMarkingCategoryOrientationNotes
W4misc hookup wireHookup 

Install SW3

Monit Switchor this turns on/off the sidetone. If you have an external keyer with its own sidetone, then this is set to off.

Install SW3 photo
CheckDesignationComponentMarkingCategoryOrientationNotes
SW3SPDT 2 positionSPDT 
CW Monitor Off/On

Install Temporary Vcc Connection

Install a temporary connection of the 13.8 Vdc Vcc supply. This will be replaced in a later phase by the permanent Vcc connection.

Install Temporary Vcc Connection photo

CW Monitor Testing

CW Monitor Test

Test Setup

Connect the temporary Vcc leads to your 13.8 Vdc Power supply.

Plug the CW hand key into the front panel KEY/PTT jack. Plug in some stereo phones.

Switch on S3. When pressing the key you should hear the side tone. Adjust the volume with 10K trimmer (Y103).

Measure voltages at control test points : pin 2, 3 and 6 (LM741 on right side of the board ONLY) = +6.1V.

See the video of this test by Brian KJ4OOS

CW Monitor Test

Test Measurements

TestpointUnitsNominal ValueAuthor'sYours
Pin 2Vdc6.1tbd_______
Pin 3Vdc6.1tbd_______
Pin 6Vdc6.1tbd_______