Hi, installed the Nextion display and it looks real nice, but I I now no longer have any power out on transmit.? Anyone know what to do to troubleshoot this?

N4GW,

What mode and how are you measuring the power?

I start with CW, verify that the signal gets to Q90, and trace it from there.? CW eliminates calibration issues as the BFO and other mixers are unused.? The first mixer is unbalanced, and the Si5351 sends the actual transmission frequency.? If you have an oscilloscope, you can verify the signal at TP12, TP2, TP3, and so on to the finals.

Does the radio still receive?? There have been instances where the Si5351 on the Raduino was damaged during the KD8CEC installation.

73
Evan
AC9TU

I was going into a power meter then to a dummy load.? ?I just tried it in CW mode and it works at full power.? Do I need to go into BFO mode on the menu and change something so SSB works?

What is strange is there is another guy on the uBitxV6 Facebook group I am a part of, and he just install a Nextion as well.? He is having the same issue.? CW fine but no SSB.? He has?so far checked voltages of all transistors and FETs they are good.? A really odd one

Did you install the KD8CEC ?program on the same Nano as was delivered? ? The calibration data is stored in the Nano. ?Swapping out the Nano requires a recalibration. ??

73
Evan
AC9TU

It was a complete board and kit with the Nextion. Just unplug the old screen and board and plug in the new one. ?All software already loaded in the new kit. ? There was another guy in the Facebook group who said after he upgraded he had to rework his mic to get it working. ?That seems odd but I tried several different mics and none worked

I meant he had to rewire his mic. ? I used a signal generator to recalibrate the radio

N4GW,

Assuming that the Si5351 clock was calibrated in the supplied board, the BFO could still be off.? The BFO's frequency is set to match the crystal SSB filter on the mainboard, which will differ for each radio.? I recommend doing a full calibration.? That should solve the low SSB power and receiver sensitivity.

73
Evan
AC9TU

N4GW,

We crossed in posting.

When you did the calibration using a signal generator, did you go through the 3 steps:
1 - Adjust the BFO plateau to the low end of a 300 to 3,000 Hz window so that you can hear the low beating tones
2 - Calibrate the master frequency using zero beating
3 - Readjust the BFO to center the plateau between 300 and 3,000 HZ.

The BFO tuning page no longer works.? I use a free PC audio spectrum analyzer instead.? The way that you get to the settings is different with the KD8CEC software, but the practice is similar to this video:



73
Evan
AC9TU

Is there a procedure somewhere for calibration of the BFO? ? I have frequency spot with the signal generator, but the BFO menu option is not intuitive?

N4GW,

You use the same process as in the video. The difference is how you get to the BFO setting using the KD8CEC software. The CEC software uses the original 16x2 display format for the base controls. If you hold in the encoder for a few seconds, a yellow box comes up. You then rotate the encoder to turn on the Setup function, open the box again, and turn to either the BFO or Calibration to make the changes.

The BFO Tuning page no longer works, so you will need another audio spectrum analyzer like one of these:



The two frequencies are 300 Hz and 3,000 Hz.

73
Evan
AC9TU

Thanks. ?That will be tough. ?I only have a portable setup and my computer is a giant tower computer. ?I won’t be carrying it outside. ? ?But the plot thickens. ?I took the radio to listen to some of the contest and noticed something really strange. ?On 10-20m, I have to listen on LSB to hear the stations. On 40 and 80m I have to switch to USB. ?The audio is excellent and crystal clear and receiver is very sensitive, just a flipped mode. ?Maybe the carrier offset is way off, but not sure how to fix that

N4GW,

There are apps for smartphones.? Look for an audio spectrum analyzer in your app store.? Sonic Tools on iPhone looks like it should work.

73
Evan
AC9TU

I calibrated it but still no output on SSB, but full output on CW.? I put the original display back in and everything works, so it is nothing on the mainboard.? Must be the board the display is attached to.? It came preloaded as a plugin card so should have been a piece of cake.? At some point I will attach the Nextion display to the original plug in card that the old display is attached to, but I have spent so many hours on this that I am tired of messing with it

N4GW,

Were you able to adjust the BFO with an audio spectrum analyzer?? The BFO must be aligned with the SSB filter characteristics to allow the SSB signal through

73
Evan
AC9TU

开云体育

All - I don't know if this info will help as I don't know what all options or mods were done.

I have my uBitx v6 with the Nextion MOD also and I had a similar issue when I added a USB hub and sound card and used the 8 pin header; Audio1 jack, to insert and receive audio to and from the sound card (SC) to the rig for digital modes.

This 8 PIN header is near the front edge behind the large knob on the right side.? Pin 1 is for the mic from the (SC) & 7 audio from the uBitx to the (SC) and I originally hooked it directly to the (SC).

I had only about .5 or so watts out when I did that.? Unhooked the (SC) and it worked fine.? I found that IF you try to add a signal to the mic pin it should be fully isolated or it drags down the signal line bad.? I used a circuit similar to the below image I scraped from Google (just the middle section for the Mic input) and that did the trick and I got the power out that I expected before adding the (SC) for digital.

I also added a few pictures of the inside of my rig.

I just got Sonic Tools so will try that again once I decided to take everything apart again. ?I have spent to many hours today on it. ? Thanks for your help. Maybe I will try it again tomorrow?