Re: BITX-40


Thank you gentlemen I now have a much better idea of how to try and fix this problem.

I also have another question:
What should I do with the bunch of remaining wires not used coming from the Raduino?

On 26 April 2018 at 09:36, Raj vu2zap <rajendrakumargg@...> wrote:
Thanks for the patient explanation for Menashe. I was presuming that he knew
about calibration.


At 26-04-18, you wrote:
Near the bottom of this webpage:
under "Calibrating the Raduino" it says
  • Attach a switch between the RED wire of the the 8-pin Raduino connector and the ground.

So we get the Bitx40 into calibrate mode by grounding the normally unused red wire
that is two positions over from the yellow tuning pot wire.
If that wire is not grounded, then a 30k resistor internal to the Nano's processor chip
should pull that wire up to 5v.

Raj suggests that you measure the voltage on that wire, see if it really is 5v as it should be
during normal operation.

If it is 5v, there is still a possibility that it is picking up a radio frequency signal that your voltmeter
does not see, and that this RF signal is causing the rig to go into calibrate mode.
The cap he suggests would bypass that radio frequency signal.

If you do not measure 5v on that wire, I suggest you add a 1k resistor from that wire
to the 5 volts from the 7805 regulator.

Jerry, KE7ER

On Wed, Apr 25, 2018 at 09:57 pm, 4Z1NT wrote:
Which wire are we talking about?
. . .

On 25 April 2018 at 15:57, Raj vu2zap <rajendrakumargg@...> wrote:
Check the voltage on the wire and if it is 5V then bypass with a 0.1 to remove noise or RF
influence and see. Do all soldering with power OFF !


At 25-04-18, you wrote:
>Has anybody have the experience of the BITX 40 [no mods yet made] deciding to go into calibration mode on its own?
>If so how did you fix it?

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