Redy for smoke test but Bitx 42


I have questions:

There is a 3 pin connector marked tuning "left over".  Is anything connected to that..maybe pre-redondo?

Something was posted about a resistor associated with CW.  May I have clarification of that?

Anything else to know?

TKS   Shep AA7MH


Check your wiring visually and with a dvm, to confirm you have no short nor open in supplying dc voltage.

Is this a ubitx? That 4.7k resistor is necessary for proper ssb ptt and for CW. It will receive without it, I think.

Extra connector? If you have connectors for everything,  that's a small puzzle. See that everything is wired.


Dexter N Muir

Wrong, Curt.  Presence of that Tuning connector defines your board as BITX40 - and yes, Shep, that extra 3-pin connector on board was for the potentiometer to control the voltage of a varicap diode in the early analog oscillator. If you have the Raduino, that is redundant: the Raduino replaces that oscillator. The inductor for that oscillator was a toroid: there should be a blank component outline in that area for that(L4), and C91. Refer to the circuit diagram at

That 4.7k resistor is only needed for proper operation of the uBITX.


many thanks!


I checked the resistance across the power connector and get a direct short.  It is open when I unplug the two two pin PS connectors.  Any ideas