PC RXTX Control Introduction


This stage is changed for kits whose serial number is greater than 100. The change is discused in this series of messages on the reflector
Change to boards with serial numbers higher than 100
The change introduces extra components to the BOM, as indicated in the labels in the above image. These extra components are not shown in the BOM(s) below.

PC RXTX Control Schematic

PC RXTX Controlschematic

PC RXTX Control Bill of Materials

Stage Bill of Materials

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

21 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W PC RXTX Control
1100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W PC RXTX Control
52k2 1/4W 1% (2.2K)red-red-blk-brn-brn red-red-blk-brn-brn1/4W PC RXTX Control
22k7 1/4W 1% (2.7K)red-vio-blk-brn-brn red-vio-blk-brn-brn1/4W PC RXTX Control
147K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W PC RXTX Control
44K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W PC RXTX Control
1Ferrite Beadaxial PC RXTX Control
610 nF (.01uF)103 103Ceramic PC RXTX Control
110 nF**103 103Ceramic PC RXTX Control
10100 nF104 104ceramic PC RXTX Control
11000 uF/25Vdc Electrolytic PC RXTX Control
1db9 connector - PCB mountjack PC RXTX Control
1BD139 NPN Transistor TO-126 PC RXTX Control
1BD140 PNP Transistor TO-126 PC RXTX Control
2BC546 NPN Transistor TO-92 PC RXTX Control
3BC556 PNP Transistor TO-92 PC RXTX Control
15K (Y502)Y502 Y502trimpot Needs to be initialized. Before installing this trimmer, adjust the resistance between the middle pin and either of the other pins to 2.5 K Ohm.PC RXTX Control

PC RXTX Control Summary Build Notes

PC RXTX Control Detailed Build Notes

Top of the Board

PC RXTX Control Top View

Install Capacitors and Resistors

Be careful - there are some easily confused values in the resistors (2.2 vs 2.7 k; 4.7k vs 47k, etc.). Note Also the locations of the seven 10nF capacitors vs. the ten 100 nF capacitors

Install Capacitors and Resistors photo
R65100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W
R391 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W
R881 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W
R272k2 1/4W 1% (2.2K)red-red-blk-brn-brn red-red-blk-brn-brn1/4W
R712k2 1/4W 1% (2.2K)red-red-blk-brn-brn red-red-blk-brn-brn1/4W
R722k2 1/4W 1% (2.2K)red-red-blk-brn-brn red-red-blk-brn-brn1/4W
R912k2 1/4W 1% (2.2K)red-red-blk-brn-brn red-red-blk-brn-brn1/4W
R932k2 1/4W 1% (2.2K)red-red-blk-brn-brn red-red-blk-brn-brn1/4W
R942k7 1/4W 1% (2.7K)red-vio-blk-brn-brn red-vio-blk-brn-brn1/4W
R952k7 1/4W 1% (2.7K)red-vio-blk-brn-brn red-vio-blk-brn-brn1/4W
R104K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
R294K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
R894K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
R904K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
R2847K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W
E11910 nF (.01uF)103 103Ceramic
E15010 nF**103 103Ceramic
E1610 nF (.01uF)103 103Ceramic
E27310 nF (.01uF)103 103Ceramic
E27710 nF (.01uF)103 103Ceramic
E30610 nF (.01uF)103 103Ceramic
E30710 nF (.01uF)103 103Ceramic
E121100 nF104 104ceramic
E134100 nF104 104ceramic
E183100 nF104 104ceramic
E212100 nF104 104ceramic
E233100 nF104 104ceramic
E243100 nF104 104ceramic
E247100 nF104 104ceramic
E267100 nF104 104ceramic
E282100 nF104 104ceramic
E62100 nF104 104ceramic
E1801000 uF/25Vdc Electrolytic

Install BD139 and BD140 Transistors

It's a good idea to test the transistor before installing - some have been reported as having shorts between base and collector.

Install BD139 and BD140 Transistors photo
E239BD139 NPN Transistor TO-126
E173BD140 PNP Transistor TO-126

Install the Remainder of the Parts

BC5x6 Transistors

Install the transistors (note that there are 3 BC556 and 1 BC546.)

Install the Ferrite Bead - see photo

E101BC546 NPN Transistor TO-92
E22BC546 NPN Transistor TO-92
E105BC556 PNP Transistor TO-92
E310BC556 PNP Transistor TO-92
E311BC556 PNP Transistor TO-92
E12db9 connector - PCB mountjack
E335Ferrite Beadaxial
E2385K (Y502)Y502 Y502trimpot
Needs to be initialized. Before installing this trimmer, adjust the resistance between the middle pin and either of the other pins to 2.5 K Ohm.

Install Permanent Jump Wires and Vin Wires

S2 and S3 from the RF-In Phase

Rewire switches S2 and S3 (from Phase 4) by removing their temporary wiring and installing permanent wiring as below

(Note: topside and underside views are provided to assist in identifying correct connection points/holes. While it is a builder's choice, it is recommended to install all of these wires on the underside of the board.)w:

Install Permanant Vin Wiring

Disconnect +Vin temporary lines from lower left corner area of the pcb and upper right-hand corner of the PCB.

Install permanent +Vin

PC RXTX Control Testing

Test Step 1

Test Setup

Connect Temporary Switches/Wires SX1 and SX2

In order to test the PC PX/TX Control, we need to temporarily hook up a couple of switches, per the diagram below:

PC RX/TX control testing should be performed in 2 steps. This is step 1:

  • Vrx,
  • Using a DMM, measure the voltage at +VTX. It should be 0V and voltage at +VRX=+12-+13.8V.
  • Set switch SX1 ON. When switch SX1 is ON, +VTX will measure +12-13.8V and +VRXwill be 0V.

Test Measurements

TestpointUnitsNominal ValueAuthor'sYours
SX1 OFF, SX2 OFF - VtxV dc0<1 (mv noise)_______
SX1 OFF, SX2 OFF - VrxV dc+12 to +13.811.85 (using 12.26 Vcc)_______
SX1 ON, SX2 OFF - VtxV dc+12 to +13.812.13 (using 12.26 Vcc)_______
SX1 ON, SX2 OFF - VrxV dc0<1 (mv noise)_______

Test Step 2

Test Setup

  • Turn SX1 OFF.
  • Connect Genesis G40 to the serial PC port directly or via USB/ Serial adapter.
  • Settings in SDR software should be set according to the DB9 connector's Pins as shown below:
    Sub D9 Pin State Function TX Action
    4 DTR Always HIGH Always HIGH
    5 GND
    6 DSR PTT/KEY ,dot EL KEYER Connect to DTR
    7 RTS LOW for RX HIGH for TX
    8 CTS Dash EL KEYER Connect to DTR
  • Turn on SX2 (temporarily installed in Test Step 1) and +VTX should be +12-+13.8V.

NOTE: for more details refer to G40 homepage: PC RX/TX control under PowerSDR and M0KGK.

Test Measurements

TestpointUnitsNominal ValueAuthor'sYours
SX1 OFF, SX2 ON - VtxV dc+12 to +13.8_______