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On Wed, Mar 24, 2021 at 10:02 AM, Gary Anderson wrote:

Another trick is to use stackable headers,

Gary,

Great idea!? Thank you for sharing!
73
Evan
AC9TU

On Wed, Mar 24, 2021 at 01:56 AM, Gyula Molnar wrote:

cut the power line to Si5351 on the Raduino board

Don, why didn't you measure the 3.3V pin as suggested?

Cutting a trace that close to the surface mount pad is going to complicate a? repair.? (higher risk of the pad lifting under heat, if you need to replace the cap)? Not recommended.

If you want to remove the 3.3V source, my recommendation would be to handle it on the Nano. (I'm just happier modifying things that I can easily restore or cheaply replace with readily available "new")
Either pull the Nano 3.3V header pin, snip it or bend it over so it doesn't make contact.? Another trick is to use stackable headers, just not on the 3.3V pin.

Rgds,
Gary

Nick,
I would wait on the RF probe.? The oscilloscope comment was really for future use.? It is a handy tool to have when troubleshooting electronics.? It can double as a frequency counter and some have limited spectrum analyzer capabilities.

73
Evan
AC9TU

Thanks Evan,

Checked those collector voltages. Q18 is low when TX on 7.150Mhz, while at the same time Q17 and Q19 are almost 12v.

I don't have a spare $300 right now. However, I do have a friend with a scope. Other end of the country, but I could send the uBitx and I'm sure he'd be happy to check a few thing out. Problematic if it's a back and forth process, but if I could be prescriptive it might work.

Best,
N

Nick,

It is not a bother to me.? I enjoy the challenge.? I just do not have any other ideas on what the issue could be.

At some point, you might want to invest in a 100MHz or higher oscilloscope.? They can be had new for around $300 or so.? It is the test instrument that I use the most.? That is IF you want to continue building kits as part of the hobby.? If you are more into operating or antenna type of endeavors, then it will collect dust until another problem comes up.

Good luck in finding the issue.
73
Evan
AC9TU

Roger that. Will check collector voltages.

Bizarrely, having taken the board out and put it back in, while transmitting CW into a Dummy Load on 7.150MHz now shows an extra Watt out output on the meter.. 4 Watts. Ditto 30m, now shows 10 Watts. I have no idea why.

Will stop bothering you (Until RF probe built...)

Thanks again.

Best,
N

Nick,

I would check that the collector of Q18 is going low when 40meters is selected when transmitting.? The collector is the one connected to D12.? Per what I sent before, the other two relays (driven by Q17 and Q19) should be off (collectors close to 12volts).

To verify that the contacts are working for all of the LPFs you will need the RF probe for your DMM.? Measure the RF at TP7, C238 / L17 junction, the C241 / L19 junction, and TP8.? All should have RF power.? Then under the same conditions test the C242 / L20 junction to ensure that the 80/60 meter LPF is not in the loop.? You should not have RF at the C242 / L20 junction.? The 20/17 meter filter would not really matter as it would pass any of the 40meter RF.? Record your readings and post for us to review.

I wish that the v6 had the same power setup as the earlier versions so that we could remove the power to the PA finals.? That would allow for ohm meter checks on the LPFs as well as a higher power supplied to the finals if desired.? Maybe in the v7?

Note:? We are going through all of this, yet the 30meter power level suggests that the LPF circuits are working.? I still do not have a reason for only issues with the power out on only 40meters.? The other readings look "normal."

73
Evan
AC9TU

Don,

By chance did you have the USB cable plugged into the v4 Raduino Nano when plugged into the mainboard and not when you tried the Raduino from the v3?? The USB cable does connect to the 5volt line on the Nano to supply power when not provided by the +5volt pin on the board.? If you did connect the USB cable to the Nano when plugged into the Raduino and mainboard, then maybe there is a potential difference between your computer and the ?BITX that is wiping out Nanos.? You would not see it if you just connected to the Nano when not plugged into the mainboard and Raduino.

Just a thought.? It seems to me that something is wiping out the Nano that is causing the Nano to draw too much current from the regulator.? Overvoltage on any of the IO pins can do that as well.
73
Evan
AC9TU

Thanks Evan,?

I was looking at the right row - (C238 - C241).

Just need to work out how to tell if the relays are playing ball...

Best,
N

Hi Evan,

To clarify: I see L1 - L4 for the 30Mhz LPF - seems visually OK on the board.

On the board, is the 7Mhz/10Mhz (40m/30m) LPF in the row with C241, C242 etc..? (Second row in from board centre?)

How can I check the correct relays are enacted? Heat? DMM? Again apologies for very basic questions.

Best,
N


?

Nick,

The KB1 relay should be identified via silk screening on the board.? The LPF is just above it in this picture.


You can see the screenings for C238 to C341 that are the capacitors of that filter.

There is not a board layout available to the public, as that is the intellectual property that HFSignals keeps preventing copies.? Attached is a picture that was provided to highlight the connections on the board.??The schematic is available on the HFSignals web page here in a link as well as a link to the new Raduino schematic:

Here is a direct link to the PDF of the schematic:



73
Evan
AC9TU

Richard,

You are welcome.? I do need to correct an error,? I gave credit to K3RTZ as my source, That is a typo on my part.? It should have been K3RTA.? Old fingers do not always go where you want them to.

Thank you for the source of the other files.? It is difficult to keep track of the author's work when they do not include a signature in the file.? I guess that can be a benefit to the author in that he is then not inundated with requests for information and changes.

73
Evan
AC9TU

First check all those bypass caps! C1 - C6 .
Remove power and use a multiplier to check ohms across them, if low then desolder and check again.

Raj

At 24/03/2021, you wrote:

Thanks Evan,

I've removed the board and visually inspected around the toroids and relays of the LPF bank. Some of the toroid solder joints do seem tenuous.

Just to be clear, how do I visually identify the 30/40m LPF? Sorry to be lame. I have to ask.

I don't have much test gear. A DMM and a NANO VNA is about as tech as it gets, and I've only used the latter for setting up antennas.

Thanks again.

Best,
N

Evan,

The ubit_35_basic.tft file I recognize immediately as the work of Rich Neese (N4CNR). Unfortunately the font he used is pretty unclear in places so it's unfortunate that the HMI file is "missing in action". He himself has now left Facebook and he's not responding to emails.

The next "batch of three" work up to a point, but have some info/components missing on subordinate screens. At least there's an HMI file among them which can be modified.

Thank you for taking the time to respond and help out. I'm surprised that with the number of uBITx radios floating around, there isn't a bigger collection of Nextion screen layouts available, but such is life!

73
Richard L-P

Hi Don,
The next step I would take would be to cut the power line to Si5351 on the Raduino board with a scalpel at the marked point.
Here's because scraping off the protective paint can restore it to its original condition with a solder.
For the test, the faulty Raduino must be put back in place.
If the stabilizer 7805 does not heat up now, it is probably caused by a short circuit in Si.
This is because you get 3V3 from Nano - since the fault persists after replacing the Nano, it's probably caused by Si.
If not, you know that the error search is done in stages, starting from the power source.
Since there are no parts that can be removed, the foil must be broken.
Then, during the repair, the original state must be restored here.

73, Gyula HA3HZ

On Mon, Mar 22, 2021 at 10:26 PM, Ashhar Farhan wrote:

the limit is really the? 2K static ram. I tried writing an FIR audio filter. There simply wasn't enough space for that. For one that is good enough, that is.

That is good to know. I'm not planning to build a usdx, but I have gone as far as to build Nano, OLED display and a few buttons on a perf-board, with the same pinout, so I could strip the usdx code down to just the audio filters to see if it would be usable as a transmit microphone audio pre-processor and an additional receive bandpass filter and digital receiver audio AGC for my uBitx. Sounds like this may be pushing the Nano beyond its realm. Maybe I'll try a Blue-Pill.

Good thing, though. A board with a Nano, a display and a few buttons can be used for all sorts of other projects. So, no effort lost.

But, I want receive AGC more than bandpass filtering, so as long as I'm this far I might as well see how well it works.?

Tom, wb6b


?

Okay it took me a while to complete my ham-fisted diagnostics. I feel like a carry only a stick when I need surgical tools to this game.? But I hate not having a radio, and my beloved uBITX is my date, so....

I observed that in addition no screen interaction, as soon as I hit the on switch, the radiuno 7805 would immediately glow like hot red coal fire. When I removed the nano but left the radiuno board in, the 7805 was normal when on.? All the voltages were normal on the pins...+5, +12.8, and ground. So all normal without a nano in the house.?

.So I assumed it was the nano causing the problem with the board?

I pulled the? V5 nano and tried to reflash it with the correct version of CEC1.2 Nextion enabled hex file. I had to re-learn how to use xloader to flash the hex (don't ask me how long that took...). No luck with the re-flash. The old V5 nano was like a cold dead fish. I opened up the Arduino IDE and tired to load the blink code, and the old nano just looked at me in non-communicative indifference. Sort of like my dates in highschool. So I assume it was DOA, as they say.?

Time to pop the cork on a new nano.? Xloader and Arudino all worked perfectly. The CEC1.2 hex flashed up like a charm.

With the new freshly minted nano, and power on, the 7805 still hit the panic button and flashed code red. So I assume while the old V5 nano was DOA, putting in fresh nanos didn't fix the problem.?

So I am soooo fortunate to have a backup V3 kit of parts (yea, and thank you Tom W7SUA), so I pulled the fresh radiuno out of the box, hit it with xLoader to flash CEC1.2, and the flash was fine. And a good thing it all works. Why? If I screw up the nano on this new radiuno, I can't swap another nano out, as it is soldered in. Yeeeeeks.

So with great fear, I pushed in the new V3 radiuno into the uBITX main board (and did I mention that the nano is soldered in, really??) and turned the uBITX on very very slowly. [Why did I do this? Did I actually think a slower turn of the on switch would slow the initial surge of electrons? What a dope.] The 7805 did not get instant boil, and the nextion screen came back. The rig was back. A happy place.? But there are a few minor issues that nag....

So, two questions:?
1. Why the 7805 would boil only when I plugged in a nano...? any nano?
2. How can I either repair the Radiuno board, or get a new one, because I know 100% that if I screwed up the first Radiuno, I will screw up another. hahahah.
3. I likely get my diagnostics wrong, due to lack of training, failure to grasp the obvious, or just being a general dope.? But the uBITX works with a new raduino, and doesn't work with the old one. So I suspect the Radiuno, Vi but I can't say why...pics of the room heating radiuno are attached.? I don't see any burn marks on the little board, but it sure doesn't seem to like trying to work ...

I finished up the N7DDC ATU this evening and have it cabled up laying on the bench and it appears to work.? I don't have any experience with ATU but when I switch from one end of the band to the other it chatters like crazy for a second or two and settles down.? I guess my antenna is pretty close as on 7.2 MHz SWR = 1,? inductance is 0 and 147 pf on cap.? When I modulate on LSB the ATU? shows 13 W but when I am key down on CW it displays 4.3W.? Interesting...

I will lay out the display hole and push button in my front panel and then integrate the ATU board into the BITX cabinet.? I have also ordered an AGC kit which shipped today.

The BITX performed well up at the cabin so it will probably be my "cabin rig" and the Yeasu FT-707 will assume the role of emergency spare.

73,

Justin B.
KI5GKD

--
Jack, W8TEE