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Erratic Tuning bitx40!

 

Hi, my bitx40 has decided to start tuning erraticly! It will tune itself in 10khz steps to the very top of the band or the bottom. And if it鈥檚 not doing that then it is jumping and tuning all over the place! One thing I have also noticed is that when first turning the radio on, the Radino with version number displays, it never used to? So I鈥檓 wondering if something has reset? Any ideas please?聽

Many thanks Carl M0CLS聽
 

What software are you using? The original? What version number displays?
 

The voltage from the wiper pin (middle) of the tuning pot is read by an analog pin on the Nano
to determine tuning.聽 Measure the voltage from that pin to ground using a DVM, it should vary
smoothly from 0 volts with the pot fully counterclockwise to 5 volts when fully clockwise.

There is no "reset" that might cause this.聽
If it worked before, then perhaps the wires from the pot got shorted or something.
The "something" means I have absolutely no idea, perhaps elves updated the firmware while you were sleeping?

Jerry


On Wed, Feb 21, 2018 at 05:07 am, <M0clscarl@...> wrote:
Hi, my bitx40 has decided to start tuning erraticly! It will tune itself in 10khz steps to the very top of the band or the bottom. And if it鈥檚 not doing that then it is jumping and tuning all over the place! One thing I have also noticed is that when first turning the radio on, the Radino with version number displays, it never used to? So I鈥檓 wondering if something has reset? Any ideas please?聽
 

I have noticed that this happens when the center pin is disconnected.

Raj

At 21/02/2018, you wrote:

The voltage from the wiper pin (middle) of the tuning pot is read by an analog pin on the Nano
to determine tuning.聽 Measure the voltage from that pin to ground using a DVM, it should vary
smoothly from 0 volts with the pot fully counterclockwise to 5 volts when fully clockwise.

There is no "reset" that might cause this.聽
If it worked before, then perhaps the wires from the pot got shorted or something.
The "something" means I have absolutely no idea, perhaps elves updated the firmware while you were sleeping?

Jerry


On Wed, Feb 21, 2018 at 05:07 am, <M0clscarl@...> wrote:
Hi, my bitx40 has decided to start tuning erraticly! It will tune itself in 10khz steps to the very top of the band or the bottom. And if it抯 not doing that then it is jumping and tuning all over the place! One thing I have also noticed is that when first turning the radio on, the Radino with version number displays, it never used to? So I抦 wondering if something has reset? Any ideas please?

 

Ok I measured voltage and getting 0.9v from fully anti clockwise to fully clockwise. There is continuity from the center pin to ground...聽

Raduino V1.01 is what flashes up momentarily when turning on.聽
 

I also noticed that the wiring for my tuning pot is different to the online wiring guide. The tuning pot is a bourns (blue) pot so obviously different to the guide, and this did work before so I assume this is correct for this particular tuning pot. The purple wire goes to the outermost pin, the yellow to the middle and the green to the innermost pin. The cap is soldered over the yellow and purple.
 

And when fully clockwise what do you read? If not near 5 volts, then trace that lug back to the source. If you do find 5 volts and the center (wiper) pin is still zero then replace that control. Any linear control from 1 K to 50 K will work. 10K is what it came with. You are running the original native software apparently.
 

So you have a 10-turn pot?
Then it should indeed be wired as shown here:



On the purple wire (slider) the voltage should range from 0 - 5 Volts,
depending on the pot position.

73 Allard PE1NWL

On Thu, February 22, 2018 12:55, M0clscarl@... wrote:
I also noticed that the wiring for my tuning pot is different to the
online wiring guide. The tuning pot is a bourns (blue) pot so obviously
different to the guide, and this did work before so I assume this is
correct for this particular tuning pot. The purple wire goes to the
outermost pin, the yellow to the middle and the green to the innermost
pin. The cap is soldered over the yellow and purple.
 

You are right Allard,

The pot would have smoked! Pot smoking has happened before here..

M0clscarl, please replace your 10T pot and wire it right there sill be no problem.

Raj

At 22/02/2018, you wrote:
So you have a 10-turn pot?
Then it should indeed be wired as shown here:



On the purple wire (slider) the voltage should range from 0 - 5 Volts,
depending on the pot position.

73 Allard PE1NWL

On Thu, February 22, 2018 12:55, M0clscarl@... wrote:
I also noticed that the wiring for my tuning pot is different to the
online wiring guide. The tuning pot is a bourns (blue) pot so obviously
different to the guide, and this did work before so I assume this is
correct for this particular tuning pot. The purple wire goes to the
outermost pin, the yellow to the middle and the green to the innermost
pin. The cap is soldered over the yellow and purple.
 

Ok I will replace the pot. Thanks for the help guys.聽
 

Can I update to a later software? If so what are the benefits of this? Thanks
 

I had this problem one time and it was the 100k tune pot opened. Just before failure the pot tuning was unstable.
and noticed the wiper action was getting rough.聽 I was using a cheaper blue Chinese pot at that time.


On Wed, Feb 21, 2018 at 7:07 AM, <M0clscarl@...> wrote:
Hi, my bitx40 has decided to start tuning erraticly! It will tune itself in 10khz steps to the very top of the band or the bottom. And if it鈥檚 not doing that then it is jumping and tuning all over the place! One thing I have also noticed is that when first turning the radio on, the Radino with version number displays, it never used to? So I鈥檓 wondering if something has reset? Any ideas please?聽

Many thanks Carl M0CLS聽


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