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Where do I find the bias adjustment procedure?

Ok please forgive me folks. I am at a point where I am having 1-2 surgeries every week for the next month. This handicaps me farther from all of the drugs that they are giving me.?
I am trying to install a Nextion 3.5" display on my uBITX v6. For the Raduino, I loaded up the file that is named: UBITXV5_CEC_V1.200_NX and it is in HEX File format. I got the file from the link that Evan AC9TU shared with me on message #93965. (Evan has made it a habit of saving my skin from my uBITX misadventures. Thank you Evan) I used the XLoader software and there did not seem to be any trouble loading it up.?

My troubles are with the Nextion Display. I format a micro SD card to FAT32. Then I load the file?ubitx_35.tft?on the SD card. I then wire up the 3.5" Nextion display to the TFT Display Header on the Raduino. Here is how I wire it up.?
RED Wire- +5V?to pin #1 on the TFT Header (I am asuming that the pin numbers on the TFT Display starts at the top and goes down then the Raduino is plugged into the uBITX board)
BLACK Wire - Ground?to Pin #2
YELLOW Wire - RX???to Pin # 5
Blue Wire - TX?to Pin #11

When I power everything up the Raduino shows that it is powered up, I can see this because of the red LED light on the raduino lights up. However the Nextion does not light up at all. I have tried this with both a 2.8" Nextion and a 3.5" with the same results on both.?
If I plug the Nextion Display up to a 5V source (when I do this I am not using the yellow or blue wires) The Nextion display lights up with a white screen that says:
SIZE: 1967505
COPY SD:
0%
And that is it, it never goes above 0%
If I were to load Reeds Arduino Sketch to the Raduino and put the stock TFT display back on everything works.
So I believe that I am doing something wrong with loading the firmware to the Nextion and hooking the Nextion up to the Raduino. I'm stuck here and I'm not sure what my next step should be.?
--
'72

Probably not.? The way the heat sink is fabricated, the transistor has just enough "leg length" to reach.? Adding a socket would elevate the relative mount which apart from some fancy leg bending would likely be more trouble than it's worth.? You'd also, probably, add some resistance to the arrangement that would create heat where you don't want it.

I don't see these devices being replaced all that often.? In my case, I did not check the transistor clamp before I started using it.? I'm not 100% certain but I believe the center or or one of end clamp screws loosen in shipment and it was only a matter of time before the device failed due to overheating.? The differing sizes of the clamped devices made this single clamp arrangement susceptible to heating problem.? Removing the LM338 and carefully clamping the IFRZ24's with equal pressure should be all that is needed to limit future replacements.? That said, I do favor a simpler, single device clamp but I've not found one to date.? When I do, I'll share my source.

The real trick in replacing these devices is disassembly.? In order to unclamp the devices, you have to remove the front panel and the RPI.? I choose to keep the two ribbon cables connected to the RPI.? There is plenty of play to unplug the RPI without disconnecting the DSI or encoders.? Since I've done this a few times, this is my order:

1. Remove top panel and speaker.
2. Loosen RPI mounting nuts and remove right side panel.
3. Remove top left front panel screw from top.
4. While holding RPI, roll radio on back to view bottom.
5. Remove front panel screws while holding RPI.
6. Unplug RPI and lift front panel and RPI as a unit.
7. With long screwdriver, remove transistor clamp screws. Note: RF shield will bend forward to access left screw.
8. Remove rear panel.? Be sure to unplug power switch cables.
9. With the left side still connected to the bottom panel, the remaining assembly can be easily positioned to access transistors.

Failed devices will be easy to identify (low resistance between connections).? I typically cut the transistor legs close to the device so there is enough leg to grab as I heat the connection.? Only the solder melts, the leg is easily pulled out.? You will have to clean up the excess solder with wick or a solder sucker but that's always the case.

Unfortunately, I did not take any pictures.? When I open the case again, I will take a few and forward.??

Cheers, Scott

Hi Jerry,

I installed the buck regulator board, replaced the finals and went through the DRIVE and PA bias adjustments.? I am back on the air!?

Heat sink is much cooler to the touch and no noticeable increase is audible noise.

Thanks for your help, Scott

sBitx number 55 is alive and well in Costa Rica.

After setting Call and grid I moved on to setting Power to zero until the mod kit is installed.
When I select WATTS and cursor down from my keyboard I can push WATTS down to 1.
If I move from 80? meters to 40M and do the same and then return to 80M the Watts display
returns to 20. Grrr. I would like that when I set a Watts value for a Band/Mode combination that
The settings will hold unless I change them. Is there a Commit function that I am not activating,
or have I found a missing 'feature' I will need to 'hack?

John
TI4JWC? N0URE

开云体育

Hi,

I have a uBITX V6 and agree with the comments.
I used a spare Arduino Nano V3 so that I can keep the original as a reference.

If you use a different Nano, make sure that the connectors are soldered on the same side as the original shipped with the uBITX V6.
You can use the PC Memory Management program to read the calibration values from the original Nano, or calibrate again from scratch.

?

There are probably two methods moving over to the Nextion display with the KD8CEC firmware.
Method 1: Probably the most straight forward.

?

Firmware - Use one of the pre-compiled hex files and write it to the Nano.

Path:

Example File: UBITXV5_CEC_V1.200_NX.hex contained in the uBITX_CEC_V1.200.zip.

Display - For a “Basic” or “Enhanced” Nextion display, you should be able to use an appropriate .tft file.
Copy the .tft to an SD card and plug it in the display. Power on the display and it should load the code. Remove the SD card and the display is ready to use.

Path:

File: Appropriate .tft file contained in UBITX_Nextion_GUI_V3.zip.

?

Method 2: This allows you to edit the code for both the Arduino Nano and Display as required.

Firmware - Compile using the Arduino IDE software

Source code from github.

Path:

I made the following minor changes in the ubitx.h configuration file to select the V5 board and to use the analogue SMETER.

Changed? “#define UBITX_BOARD_VERSION 2” to “#define UBITX_BOARD_VERSION 5”

Changed “#define USE_I2CSMETER” to “//#define USE_I2CSMETER”

Display - I have used the 2.8-inch Nextion Discovery display and it seems to work.
I had to make the same changes in Nextion Editor Ver.1.63.3 with respect to the error message identified.

I also changed the jSMeter vscope from "local" to "global" to avoid losing its value when switching between screens.

The “Discovery” displays seem to be slightly cheaper than the “Basic” series at the moment, but you will need to use the Nextion Editor.
There is a Chinese version of the Nextion display called “TJC” which tends to be cheaper.
This can’t use the same .tft file as the Nextion, and is not supported in the English version of the Nextion Editor.

?

73, Dave (G8PTN)

Toroids and pitfalls?

What were the problems?? Toroids for use in HF have been the standard for high performance vs size for a long time.? Are there suddenly problems?? The only problems I can imagine are poor quality/unknown materials related to buying from questionable sources, or just choosing the wrong core material.? For the size, toroids using the proper magnetic material will give one the highest Q.? If not, then manufacturers would certainly be using very low cost plastic cores.? For?VHF, phenolic toroid cores have been used for decades because at VHF magnetic materials become counterproductive.? For HF if you choose not to use a magnetic core, then pretty much any RF neutral material will suffice.? One could use bobbin cores, rubber, balsa wood, 3d printing, whatever.

If you want to check your measurements, you can use MicroMetals "Toroid" program:



Just choose the closest core size, choose material type 0, input the desired inductance and it will give you the number of turns you need and show you the peak Q frequency as well as the self resonant frequency (which can become a problem as the number of turns grows)

73.

开云体育

HF Signals said they would be delayed, as I recall

Hello all,

Has anyone received their Sbitx basic kit with the LM338 repaired with the new switching regulator yet?

The reason why I ask is that I ordered my Sbitx basic kit on August 9th and it hasn't shipped yet, I'm wondering if the repair of the Lm338 is holding the shipment up?

Thanks,
Robert AG6LK

Both IRFZ24Ns are shorted. I removed them an tested them with a multimeter as I did with the original pair that blew. I also tested the second pair before swapping them in. (I ordered a set of 10 on Amazon when the first pair blew.) I installed a third set late last night but I’m not going to power it up until I have more time. Interestingly I seemed to have no problem earlier this week using cw. The only thing I changed is to increase the IF value from the default 41 to about 85 since it improved the signal on receive. I know that the uBitx runs transmission through the same chain of amplifiers as the receive function, just in reverse. Could increasing the IF value on the sBitx screen damage the PA MOSFETs?

Dear Barry,
Very verry interesting.?? Sounds to me that coil form is a winner.?? Where did you buy the thread bobbins??? I am in the hunt.?? I am putting a test fixture together today so I can start testing materials.
but you may have hit on the most desirable form for the coils.
Take care and have fun. Thanks for sharing.
73 Dave WA5DJJ
SUPER QRSS GRABBER https:www.qsl.net/wa5djj/

On Mon, Aug 15, 2022 at 12:01 AM, Ashhar Farhan wrote:

?

These will go out by Thursday if all is well.

?

?

- f

Will there be any notification they've shipped, and by what method? Not wanting to create any additional work for the HF Signals team, just nice to be able to keep an eye out for the delivery, especially as erratic as my usps delivery can be.

Opened it up - something was blown from the PCB... see pictures