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_______