Re: Help with partially fried QMX
I am also trying to diagnose a fried (?) board, Rev 4, ordered and built in the last couple weeks. wound for 9V.
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As posted elsewhere, i had an issue with a powerboard, replaced it, and it worked fine for about 12 hours.? made some FT8QSOs (two new DXCC for me even!), and some CW contacts and RBN showing well into europe and across US.
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But then it all just suddenly stopped.? All terminal diagnostics are pretty much exactly as shown in the operation manual, the only issue being no power out on pressing T.? What i did discover was continuity between the center pin (radiator) of the BNC connector and ground. I removed the BNC connector but the issue turns out to be with the main board. With the BNC connector removed, there is no continuity between the female center and the outer housing.
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Any suggestions on where to look first?
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Thanks in advance.?
JD
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Re: Gibberish characters appended onto end of Message 1
I figured out how to delete the entire message. Then, I re-entered the message but I am still getting gibberish sent at the end of the message that I did not enter.
The gibberish is K0****AS?
This renders the message function to be useless.?
I hope no one is listening to the CQ I'm sending.?
Buying a pre-assembled unit, I was hoping not to be doing debugging. Oh well.?
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QMX terminal using GNU screen
Somebody asked me how I access the QMX terminal settings if the radio is connected to a headless Raspberry Pi that I can connect to only with a text based ssh connection (or through a browser window with ttyd). Without a graphical desktop system, tools like Putty don't work. So, here are some notes on using GNU screen for this.
GNU screen is a text based terminal multiplexer that is widely available on Linux machines. If it isn't installed on your raspberry pi, you can install it with 'sudo apt install screen'. I often use it so that, after I connect to the pi using ssh, I can create multiple windows (tabs) that I can switch between to run multiple programs. If my ssh network connection to the pi is closed, programs running in screen windows (like ardopcf or pat) continue to run, and I can reconnect to them later. See 'man screen' or various online articles and videos for a description of this normal usage.
A less well know use of screen is to connect to a serial device with it. So, if the QMX is connected to the pi with a USB cord, so that it appears as virtual serial port '/dev/ttyACM0', you can open the QMX terminal using the command: 'screen /dev/ttyACM0'.
Just like when connecting with Putty, this displays a blank black screen until you press <Enter>, and then you will see the QMX terminal menus. Keyboard input including arrow keys should then work as expected.
However, there are two things that are different than when using a program like Putty. First, Ctrl-Q, which Hans chose to use to back out of various sub-menus and screens, does not work when using GNU screen. To send Ctrl-Q to the QMX, you need to type Ctrl-a and then q. Second, to close a screen window, usually after selecting the 'Exit terminal' command in the QMX menus, type Ctrl-a and then k. This will prompt you with 'Really kill this window [y/n]', so type y.
If you are already running screen, perhaps with multiple windows, you can also open a new window to connect to the QMX by typing Ctrl-a and then typing ':screen /dev/ttyACM0' (without the quotes) and pressing <Enter>. Once you type the colon (:), it and the remainder of this command will appear in the lower left corner of the window until you press<Enter>. When you are done, typing Ctrl-a and then k will close this window but not any other screen windows that you have created.
Hopefully some of you will find these notes useful. Using the QMX terminal is even more important now with the changes in the new SSB beta firmware.
Peter LaRue
AI7YN
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Re: Tone or birdie every 500 Hz in USB mode
I can also confirm that the CW sounding noise was from the GPS, however after removing the GPS, there is still a high pitched tone on 12m and 6 meters that wasn't there before. I think it's on all bands above 17 meters, but the noise is higher on 17 meters and 10 meters, even with the dummy load, so it's hard to hear the tone on those bands.
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73, Dan - W2DLC
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Steve, good job.
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73 Ludwig
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
On Wed, Apr 2, 2025 at 12:26 PM, John Laidler wrote:
I can find micriophones for sale which say they are suitable for Baofeng and Yaesu.
Baofeng (and Wouxun and other Chinese rigs) and Kenwood 3.5mm+2.5mm plugs share the same pinout/spacing.? The programming cables seem to be interchangeable, too.
I bought a Retevis clone mic, cut off the plug and rewired it.? I tried fabbing an adapter first but it was too clunky.??
73, Don N2VGU
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Re: QMX+ rev 3 freezes shortly after boot
On Wed, Apr 2, 2025 at 05:32 AM, Michael Shiplet wrote:
- battery plugged in, radio turned off: 0.00A, ~12.08V
- radio turned on, normal operation: 0.06-0.10A, ~12.08V
Hello Michael, that's fine.
- radio turned on, frozen: 0.18-0.20A
A bit much but no heavy short or so.
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This case is interesting and the situation is cloudy. Hard to debug from afar. And debugging maybe dangerous for the QMX. There are two reason:
- VDD = 4.5 V is higher than the rating and heavy stress for most of the IC connected to VDD. The controller, the heart of the QMX, is connected to VDD.
- VDD = 4.5 V and a higher current looks like the zener diode D109 is in action. With regard to the characteristic the diode current could be 120 ... 160 mA and the power 540 ... 720 mW. This diode is rated 500 mW and may heat up to much from to much power. If this diode will break the resistance could go to a low value or a high value. For first case VDD would be lower and no problem for the controller and for the second case vice versa bringing more danger for the STM32 and others.
So staying (for a while) in the failure status is dangerous but how to debug not being in this status?
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And I see one more problem. I don't know is the controller stopping because VDD is to high or is VDD raising because the controller stops? Without a proper running controller no proper running SMPS for VDD and VCC.
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Could you check please R110 and R112 (good soldered and not damaged). Via this voltage divider a feed back signal from VDD is produced to control VDD.
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There are some good points in posts before:
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George wrote:
Also replug the front panel and look at the display connection and while it's out check for a tiny bridge or a whisker that may be in there. That will answer a lot of questions?
And please make a careful visual inspection using a strong magnifier. Look for solder bridges, blobs and whiskers.
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George wrote:
Also do you have the internal GPS? if so unplug it.
Also is it in a case? If so remove it.?
And when you test for success and you reach the faulty state again please remove the supply immediately.
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Stan wrote:
I'm wondering if you have a temperature-dependent issue that causes the 5V supply to get shorted to Vdd, pulling Vdd up and Vcc down.
Maybe also take a resistance measurement (with power off) between Vdd and Vcc.
Stan wrote:
When you said you could reproduce the problem by trying to attach the terminal, did it happen when you connected the cable, or when you hit enter in the terminal window to bring up the menu?
I'm curious about your answers.
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73 Ludwig
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Re: Help ID QDX Digital voltage and band option
Toroid colors indicate a low band build. The high band QDXs never came with any red toroids. So likely an 80-20m. 12V build is the most common I think, but as was said, try 9V and check power output.?
You could go into the serial terminal application (putty) and connect to the QDX and look at the band configuration to confirm as well, as far as band setup.
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As always, I'll suggest the diode across L14 mod, too. :-)
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-Nate
N8BTR
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Thought i would update - indeed it was some short on the power board.? Got the new boards, slapped it in praying i would get back to at least seeing the USB drive but in fact the QMX booted up and was working just fine.
...until it wasn't.?
Made CW and FT8 QSOs and was hitting across north america and into europe on RBN then suddenly nothing.? I am assuming i somehow popped my BS170s??? no power showing as output on teh diagnostic screens, otherwise everything seems to be within optimums as shown in the operating manual.
Any thoughts?
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Also, my screen is retina-seering bright.? No contact between screen pin3 and power board as suggested elsewhere.? i have removed the r306 and put in a 110ohm resistor.? Brightness has come down, but i am still at the very counter-clockwise end of the contrast control to see anything.? Any movement of the pot counterclockwise and the screen washes out.? Would that be indicative of anything underlying problems or is that simply the screen's nature?? I have much better contrast control on my old QCX mini
JD
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Re: Gibberish characters appended onto end of Message 1
How do you delete a message?
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My pardon, I thought that was what we were talking about. As the fictional character Emily Latella would say: "Never mind." -Chuck Harris, WA3UQV On Tue, 1 Apr 2025 19:56:03 -0700 "Paul - AI7JR via groups.io" <paul.hanchett@...> wrote: Chuck--
If I understand correctly, it's only the QMX+ that gets powered up,
firmware loaded, and tested... On Apr 1, 2025, 19:47 -0700, Chuck
Harris via groups.io <cfharris@...>, wrote:
A really good question that you should ask yourself is:
Does your radio work when you power it up?
They all come with firmware installed for the factory
tests of the SMT parts on the board, so if your radio
is assembled correctly, it should play.
If it doesn't, concentrate on that. Save the firmware
loading for after you have fixed any construction errors.
-Chuck Harris, WA3UQV
Tue, 01 Apr 2025 18:22:27 -0700 "Bill KJ5IVB via groups.io"
<Wdbuck@...> wrote:
Just finished QMX build and I can’t get my Mac to recognize the
USB so as to upload firmware. ?I am powering with a 7v power
supply. ?I am using USB c to usbA and then an adapter. ?Have
tried two other cables with no success. ? I have seen all the
tips on YouTube and also page 63 in the manual. ?Feel like I’ve
wasted $150 on this radio and likely never to get it to work. ?I
will try on a Windows machine if I can borrow one this week.
Other than that don’t know what to do.
Bill, KJ5IVB
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Re: Debugging BS170-related issues
Well, I'm getting closer after the meltdown. Q503, Q507 and all the BS170's replaced.? Power output 0.6 watts. Drawing 350 mA from 12 volt supply. Gate voltage on the BS170's seems okay - 2.6 volts key down.? PA voltage 9.6 volts, key down. Swapped BS170's. No change.
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Where do I measure/check next ?
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Thanks and 73,
Steve, N2IC
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Re: V6 Sythesiser PCB link wire
Well it’s a lovely job. ??
Only noticed it under high magnification !?
Thanks Bruce! Mr Levent is very good at such things and after some hundreds he was getting even better! But still, I will try not to make that PCB mistake again next time...
73 Hans G0UPL
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Hi QMXies.?
As a sota enthusiast i was missing a working clock (on the QMX .. not QMX+) regardless if batteries have been removed before.
There is everything there also in QMX, but the 32kHz Q and the buffer battery.
I (carefully) released pins 6, 8, 9 of the STM32 from the PCB, soldered 3 thin wires to the elevated pins ant fixed them with epoxy glue. Then attached a 32kHz Q to 8 & 9 pin wires.
As i don't need the PTT output for sota, i removed the PTT connector, which made room for the CR2016, attached to pin 6 wire.
Settings "real time clock"? set to QMX+? RTC? and "set time"? -- voi la. Now the RTC keeps on running while QMX is in his transport box without any power attached :-)
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I have to confess, you need some skills in working with very small soldering tips under the microscope, as the pins of the STM32 are really close together. Solder bridges don't have to bring you out of concept ;-)
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:-) Wolfgang OE3WHU  
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Re: Power Failure on New Factory-Assembled QMX+
To close the subject, the problem was with me, not with the QMX+.?
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I don't know what I did last week (may have been transmitting on 10m into a 15m tuned dipole), but the rig finally would not switch on and I thought I had fried it.? A few days later Hans asked me to check voltage on receive.? Honestly!? I was sure that it wouldn't switch on.? But it did, and is working flawlessly.
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Lesson:? If you keep trying to transmit with an 'S' constantly appearing on the display, and finally the rig won't switch on, don't despair.? Give it some time, check and re-check your settings and try again.
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Tim Ei2KA
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QMX+ points A continuity check to ground question
On p25 of the Rev 3 QMX+ manual, there is a check for continuity to ground from three points A. BEFORE installing T501, when checking the three points A,? I get about 15 ohms with the DMM black lead on the ground connection, but open circuit (desired) with the? leads reversed (ie red lead on the ground connection). Is this to be expected? The 4 BS170's ARE installed.
I am troubleshooting a continuity check problem identified after having installed T501 (now removed).
Thanks
Steve AK0M
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Re: Help ID QDX Digital voltage and band option
Hello Dave,
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Dan's suggestion is good with one addition:? do the test into a 50-ohm dummy load.? Antennas can cause higher or lower power due to differences in impedance.
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73
Evan
AC9TU
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Re: ProgRock2 programming??
On 02/04/2025 14:59, cct314159 via groups.io wrote: - Even though they are "rated" for "12 volts" *don't even think about running one at that voltage:*? I'd avoid going above 10.0 volts. Yes, that reminds me. I tested with 12 volts and it certainly got a lot hotter than I expected. The ones I use are fed from 5 volts and keep cool. 73 Alan G4ZFQ
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Thank you, Ludwig. That does it. PA voltage now 0.3 instead of 10.9.
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73,
Steve, N2IC
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Re: QMX (not-plus) power issue
What did you come up with, Michael?? Did you ever get your 20m power up beyond 1.2w?
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Joshua
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Braden Glett
Daniel Conklin
Donald S Brant Jr
Joshua KJ7LVZ