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Hi, my name is Lorenzo and I write from Italy.
This is my first message here, so nice to virtually meet you all!
I have a sBitx v3 board SN 0634, and while I'm 3D printing the case, I did some tests, after upgrading to v3.02.
It works perfectly in RX, in all modes I tested (SSB, CW and FT8) but when trying to transmit I got no output at all. The power meter reads 0W and SWR 1.0.
I tried it in FT8 and CW, and when switching to TX, the supply current rises from 400mA to 1.2A, but I have no power on the BNC connector. I tested with a tuner with built-in wattmeter, using my antenna and a 50W dummy load, no changes at all, regardless to the Drive setting.
The waveform display only shows a yellow straight line, without any modulation. As I'm an absolute beginner in the sBitx world, I don't know if I'm missing something. I checked the IRF510s and they seem fine. I also measured the voltage between Gate and Source while switching to TX, and it reads 4.33V, so I suppose the TX switching works fine. Any idea is greatly appreciated! Thanks!?
?73 de IU5RDU!
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Sorry, I forgot to add that I'm currently using an HDMI monitor (without audio) and I already tried to add the "noaudio" parameter to the config.txt file.
Thanks
Lorenzo IU5RDU
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Lorenzo, Can you check that the drive level is 100 on cw? - f
On Mon, Feb 5, 2024, 3:15 AM Lorenzo IU5RDU via <assali_fucina_0h= [email protected]> wrote: Sorry, I forgot to add that I'm currently using an HDMI monitor (without audio) and I already tried to add the "noaudio" parameter to the config.txt file.
Thanks
Lorenzo IU5RDU
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About 1 in 5 uses of sbitx v3 unchanged from factory, I get no tx output ( only use ft8) as well. Restarting sbitx does not fix the problem. I must reboot the system to fix the problem.?
On Sun, Feb 4, 2024 at 15:39, assali_fucina_0h via groups.io < assali_fucina_0h@...> wrote: Hi, my name is Lorenzo and I write from Italy.
This is my first message here, so nice to virtually meet you all!
I have a sBitx v3 board SN 0634, and while I'm 3D printing the case, I did some tests, after upgrading to v3.02.
It works perfectly in RX, in all modes I tested (SSB, CW and FT8) but when trying to transmit I got no output at all. The power meter reads 0W and SWR 1.0.
I tried it in FT8 and CW, and when switching to TX, the supply current rises from 400mA to 1.2A, but I have no power on the BNC connector. I tested with a tuner with built-in wattmeter, using my antenna and a 50W dummy load, no changes at all, regardless to the Drive setting.
The waveform display only shows a yellow straight line, without any modulation. As I'm an absolute beginner in the sBitx world, I don't know if I'm missing something. I checked the IRF510s and they seem fine. I also measured the voltage between Gate and Source while switching to TX, and it reads 4.33V, so I suppose the TX switching works fine. Any idea is greatly appreciated! Thanks!?
?73 de IU5RDU!
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Hi Ashhar, I checked and even at 100 I got no output. I attach a screenshot. Thank you! Lorenzo 
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Lorenzo,
? I'm just guessing the cause of the problem because I can't do it to see and measure it.
Please remove the pcb from the housing (so that the housing is not damaged during soldering).
There are two ferrite rings near the antenna connector and a diode (D27, D28) nearby.
You should measure these diodes at direct current. You can easily unsolder it and put it back in the same way.
They provide the control signal for the output signal measurement.
These are 1N63 or 1N60 type Ge diodes. If these are damaged, there is no output signal status display.
If you manage to get it, it is worth selecting ones with almost the same conductivity and incorporating them.
Don't ask how I know.
--
Gyula HA3HZ
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ps.: if you have the opportunity, use the device from a current-limiting power supply so that it has a long life.
I had to replace the D27 and D28, and then managed to destroy the original IRFZ24Ns, because I used them from a battery, without current limitation.
Since I've been using it with current limitation (12.5V 6.00A), I've made more than a thousand ft8 QSOs on 7-14-21 MHz with a vertical Loop antenna.
I've been using it since mid-November.
--
Gyula HA3HZ
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Hi Gyula,
thanks for your message!
I already checked those diodes and they are good. I think the problem is that there is no modulation, actually.
Thanks!
Lorenzo IU5RDU
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Lorenzo, The tx current is stuck at 1.2A, this means there is no modulation. Do you have an oscilloscope handy?
On Mon, Feb 5, 2024, 2:28 PM Lorenzo IU5RDU via <assali_fucina_0h= [email protected]> wrote: Hi Gyula,
thanks for your message!
I already checked those diodes and they are good. I think the problem is that there is no modulation, actually.
Thanks!
Lorenzo IU5RDU
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Hi Ashhar,
yes, I have an oscilloscope, I can do tests.
thanks!
Lorenzo
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Ashhar,
I was thinking about checking the signal "AUDIO-MOD" coming out from the WM8731 and following its path through Q6. What do you think?
If I understand correctly, all the signals are generated by the WM8731 codec and sent both to the LHPOUT (pin 9), to be sent to the earphone jack and speaker, and to RHPOUT (pin 10) to be sent to the TX stage through Q6, that's been enabled by the "TX" signal, correct?
Tonight I'll check and I'll report here. In the meantime, just wondering, could there be any reason why the RHPOUT output has been muted by software (maybe some corruption of the files during shutdown or something similar)?
Thanks!
L.
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Oh, I forgot to add that during TX I can correctly hear the signal through the speaker (CW and FT8), if that can be helpful to the diagnosis.
L.
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Hi,
I did some measurements with the oscilloscope. No signal (just noise) on the AUDIO-MOD line, I tested it on the node between pin 2 of Q6 and R56. Does this test help?
By the way, I connected a DSI touch screen to the Raspberry and nothing changed, so the issue it’s not HDMI audio related.
Thanks!
L.
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 Just an update… I think I found the problem!
I tried to install the old Sbitx version from the website in another SD card then I did the update… and it worked!
Then I changed the OS locale to Italian and it stopped. I changed again to US and it worked again. So I switched back the SD, changed the locale to US and… everything’s working!!!
Hope it helps!?
Now… let’s start the journey in the Sbitx world!
L.
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I finally got my Sbitx yesterday and am working on setting it up.
I noticed in cw mode the on screen keyboard is not available,? and the button kbd/off shuts down the radio app. Is this one of those bugs in version 3 needing upgrade?
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Did you change the OS language, by chance?
L.
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It looks to me by this thread, that one must always keep a working version available.? First determine if it is software or hardware before opening to measure things. Gone are the days of just opening and measuring! But that is good. Cuts the work way down.
I finally got my Sbitx yesterday and am working on setting it up.
I noticed in cw mode the on screen keyboard is not available,? and the button kbd/off shuts down the radio app. Is this one of those bugs in version 3 needing upgrade?
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Hi Scotty;
The work-around for this bug is to set the task bar at the top of the screen to auto-hide.
A proposed software fix is on github being reviewed now.
73; Steve, N3SB
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HA3HZ
Scotty R