Qmx plus rev 2 not powering up
Dear group
Took me a long time but finally I have finished a build of a Qmx plus rev 2 (my 3rd kit) and when powering it up nothing happens.?
so I start debug the power supply with the following tests:?
initially power with 12v (500ma) and nothing no display no nothing power consumption arround 9ma when the button is pressed, I release the button and back to 0ma.
so I have check if the 3v out where in ic101 with the button pressed and nothing there. Than the input and strangely nothing there even with the buton pressed. Next step I apply directly 7v on its input and I get 3v on the out put. Seams working consumption also increases to some hundreds of ma meaning the STM32 can be working.?
then I was checking q101 and q102 and I get when I press the button arround 5v on q101 out and 11.5 on q102 out with 12v input again.?
the problem is that on the ic101 I don’t see the 11.5 v. Seams that the line is broken.
?
did some one experienced something like this??
what should I do next??
73
Azgael
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Re: Should I just go ahead and order a QMX+?
Gwen,
Just keep using your wonderful rig and enjoying all those neat keys you have. ?SSB, especially CESSB is just a passing fad (I heard that somewhere someplace back in the 1960s). ?Use what works, CW! ?Ha! ?Hi Gwen. ?
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On Mar 29, 2025, at 3:45?PM, Gwen Patton via groups.io <ardrhi@...> wrote:
? Hans,
When the SSB supporting firmware reaches a stable status, will it be posted on the QRP-Labs website somewhere with instructions for installing it? I am leery of trying to figure it out from the input of a metric buttload (491 liters hi hi) of widely-spread mailing list posts. Mostly, I don't want to read something wrong, or do the installation wrong, and either brick the radio or release the Magic Smoke?.
?
Alternatively, is there a source that shows the instructions for acquiring the firmware and installing it already? I want to experiment, but I want to engage in it safely, not unduly risking my radio.
?
Thanks,
73,
Gwen, NG3P??
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Re: QCX Challenge - March 2025
GMT +1? ?also known as? British summer time..? ?for the United kingdom.. Scotty GI0BEY
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Re: QMX SSB and non-FSK digimodes
Hi Jindra?
In SSB firmware 003 there's a bar under the 'A' when in transmit with audio. When in transmit without audio it would be a dot under the 'A' (top left character of the display, the VFO symbol). So this can help to debug issues.?
I've been using Pat with ardopcf on my Pi400 on 20m and I get WinLink working reliably daytime with 3W to OCFD antenna, to my nearest server which is LZ3CB 635km away. So it does work... Yes in USB mode (prior to SSB firmware I had no luck in the FSK-only Digi mode).
73 Hans G0UPL
Thank you. Now I tried to transmit from QMX in USB mode but something does not work. RX gets quiet but PTT/TX indicator on QMX does not appear and there is no output. ARDOP drive level is 100, CAT command is TX; and SSB firmware is 003.
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Jindra
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Re: SSB audio distortion #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
Yes, we think we have discovered that if the Phase Error calibration does not complete (yours only went to about 600 on the x-axis), that the audio is corrupted, presumably because all of the rest of the values in the table are not initialized.
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If you can repeat that calibration and make it finish, your audio will sound good again with PD turned on.
Some of us were able to make the calibration complete by adjusting the center frequency or band edge frequency in the Band Configuration screen.? We don't know why this makes it complete, but playing with the band frequency values often works.???
You should make note of the original values, and restore them after you get the Phase Error calibration plot to complete.
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Hans has this on his list to look at when he returns from vacation.?
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Good luck, Stan
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Re: QCX Challenge - March 2025
Good point Martin,?
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I forgot about it myself.
So for (most of) us Europeans, it's at 15:00 and 21:00 CET
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Luc ON7DQ
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Re: SSB audio distortion #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
I have very bad audio distortion on 80m band with PD tuned on. With PD turned off, I'm?
satisfied with the audio quality.
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I think there's something wrong with the calibration. Here's my calibration result on 80m:
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--
73, de BD8BTE
op: Lun Yang
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Re: 74ACT08 damaged and LCD is all blocks
When you enter the diagnostics screen, the Tx voltage is turned off, so it can be tested and we can see it turn off and on.
As soon as you exit the diagnostics screen, it turns back on.
If you read Hans' description, they found that certain things work better in receive if they leave the tx voltage on.? But in receive, the TX signal into IC503 is off, so the BS170s never get turned on, never conduct current.? At least if IC503 isn't broken...? So either:
a) IC503 was broken first from an over-voltage on the 5V, with floating or shorted-high outputs that caused the BS170s to fail, or
b) as I think Ludwig suggests, the BS170s had suffered some damage, and finally broke, sending a 12V over-voltage into IC503 outputs, frying it.
And I think Ludwig's version is more likely, since I have no idea how you could get a severe over-voltage on 5V without also damaging the 5V smps protection diode - it would clamp the over-voltage to ~5.6V, except for maybe a fast-and-furious spike that was faster than the clamping speed of the diode.
Or maybe it was something else that we haven't thought of...
?
Stan KC7XE.
?
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Re: 74ACT08 damaged and LCD is all blocks
The broken IC503 switched one pair of BS170 on the whole time. The high current was flowing via these BS170.
Ludwig, you were right. I measured the resistance between the terminals. All 4 BS170s were damaged. I guess the broken IC503's outputs were floating which in turn caused high current flowing between the drain and the source? But I (think) didn't attempt any TX so the drain voltage should be close to 0 all the time? No? Anyway, all 4 BS170s replaced.
The PA voltage is switched on the most of the time (also in RX mode).
I don't quite get this part. Transmitter Voltage is at 0.5V in RX mode. Or you mean sth else?
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73 N6HAN
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Re: 74ACT08 damaged and LCD is all blocks
Accidental TX when the band is selected or running any of the Hardware test tools or SSB Calibration on those bands may cause failures, since they won't be terminated correctly. ?So I hope those bands weren't included in your SSB Calibration; in its beta condition who knows if it is honoring that TX disable setting.
Thanks. I didn't consider the termination. I did disable TX on those bands. But I'm going to install them to avoid any risk now.
?
I highly recommend something like this. ?It sounds like the combination of your trigger cable and that one charger were not doing what was expected.
I have a similar one (identical functionality, but different shape). That charger indeed generates the voltage what the trigger cable asks to, so I really don't know what happened.
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73 N6HAN
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Re: QMX+ high pitch noise on power. Now dead.
Set the current limit to 250mA and the voltage to 7V until it starts up and works correctly in receive mode?
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Re: QMX+ high pitch noise on power. Now dead.
My dad has a nicer power supply that does have current limiting. I can test on that tomorrow. What is the maximum amperage I should allow?
I think I could replace the diode but if I can't my dad definitely can. He was trying to help me but he just doesn't understand the circuit that much.
It is a bit hard to test a zener, especially a low-voltage one in circuit.
I just measured mine with the diode test function of my multimeter, and it measures 0.31V in one direction, and 0.44 volts in the other.
I don't know what that really means, but if yours is broken, you will likely see something different.
?
The way I have normally tested D109 is to remove it, then power on and see if the rig wakes up normally.? If it does, I know that D109 was bad and replace it.? I do NOT recommend you do this, because you have no current limit on your supply, and D109 will not be there to protect your processor and other 3.3V devices if there is still a problem.? Instead, I would replace it before trying to power on again.? Then if there is still a problem, D109 will conduct the over-voltage to ground and not harm your other ICs.
?
D109? is very small and nestled between two other devices, so be sure you have the practical skill (practice helps a lot) to replace it before trying; otherwise send it to someone else to fix.? I can look, I may have an extra one I can send you if you don't have one but do have the skill to replace it.
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Stan KC7XE
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On Sat, Mar 29, 2025 at 10:26 AM, @Ludwig_DH8WN wrote:
On Sat, Mar 29, 2025 at 01:17 PM, Brien - KE7WB wrote:
Plug in the USB cable from computer to QMX and then try to turn on QMX.? This yet to be fully understood scenario worked for me on a couple of occasions.
Brian, if this works when you can't switch on your QMX without the USB cable something is wrong with your setting / your QMX!!!
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73 Ludwig
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Ludwig,
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Possibly, but it has not happened to mine for quite a while (so no opportunity to explore further) and my QMX has been working fine.? I did add some ESD mitigation and have not had any abnormal operation since.
?
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Re: Multibanding the 50w amp question
Thanks Gregg,
?
I could totally go that route as well. This is just for CW, and it's good to hear the values for the LPF kit worked for you (I already bought the bigger toroids and higher-rated caps). Say, I'm sure I could look this up using the search function, but while you're here, what kind of output did you get on 15 meters? 73, Sam
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Re: Multibanding the 50w amp question
Sam,?
One other thought ...
Another 50W AMP kit plus the nice enclosure is just under $46 plus shipping.?
I ordered three and the shipping was the same as a single kit. Built one of them for 15m using values from the QRP-Labs LPF kit information with? purchased capacitors that matched the V Max Specs of the 50W supplied components. I also researched turn windings for the kit supplied toroids to get close to the inductance suggested for 15m.? Made good contacts on FT8 and WSPR.?
And just in case,? the 50W kit is not a linear so SSB is likely not going to work.
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Re: QMX+ high pitch noise on power. Now dead.
It is a bit hard to test a zener, especially a low-voltage one in circuit.
I just measured mine with the diode test function of my multimeter, and it measures 0.31V in one direction, and 0.44 volts in the other.
I don't know what that really means, but if yours is broken, you will likely see something different.
?
The way I have normally tested D109 is to remove it, then power on and see if the rig wakes up normally.? If it does, I know that D109 was bad and replace it.? I do NOT recommend you do this, because you have no current limit on your supply, and D109 will not be there to protect your processor and other 3.3V devices if there is still a problem.? Instead, I would replace it before trying to power on again.? Then if there is still a problem, D109 will conduct the over-voltage to ground and not harm your other ICs.
?
D109? is very small and nestled between two other devices, so be sure you have the practical skill (practice helps a lot) to replace it before trying; otherwise send it to someone else to fix.? I can look, I may have an extra one I can send you if you don't have one but do have the skill to replace it.
?
Stan KC7XE
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Re: Figuring out why no keyer sound and updating my QMX Menu Reference to Firmware 1_01_003
Sorry, I didn't mean to send you down a long rabbit-hole.? I have no idea how to make airspy work, either.? Someone else here used NaP3, and posted the way they set it up, and that's what I have used.? So if you ever want to try again, maybe search these messages for NaP3 and use that approach, or post a message asking for a program and setup that work nicely with QMX.
Stan KC7XE
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Re: Multibanding the 50w amp question
Thanks Nate! Well, this looks promising. I was also considering just building a 20-meter amp and being happy with external filter for 30 and 40 meters, but of course a little extra on the higher bands would be nice. I'll just have to do some research on the highest band I can pull off then. Also, while that board might not work I appreciate you sending it along.. I like the idea of using relays to interface with my rig for automatic band switching so fortunately (unfortunately?) this project just got more complicated. best, Sam
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Re: 74ACT08 damaged and LCD is all blocks
Not installing the BPFs/LPFs shouldn't cause a problem.? You should disable TX for those bands in the band config menu, otherwise it is risky.? Accidental TX when the band is selected or running any of the Hardware test tools or SSB Calibration on those bands may cause failures, since they won't be terminated correctly.? So I hope those bands weren't included in your SSB Calibration; in its beta condition who knows if it is honoring that TX disable setting.
?
I purchased a couple of very inexpensive (Ali express) "USB&DC Digital Tester"s (mine are Atorch brand) that I always connect inline with a new power source before and while initially using it with my QMX.? It shows voltage and current, and also the PD and QC protocol triggering status when on a USB port.? It has both USB and 5.5/2.1 digital in/out ports.? So I can be confident of the voltage before I plug it in, and watch the current while it starts up.? I highly recommend something like this.? It sounds like the combination of your trigger cable and that one charger were not doing what was expected.
?
Stan KC7XE
?
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Re: Figuring out why no keyer sound and updating my QMX Menu Reference to Firmware 1_01_003
I just spent hours at trying to get airspy working it will not connect. Don't worry I do not expect anyone to try to explain it online. :)? It was just a curiosity thing if it would work.? Just wanted to try it. Thank you for mentioning it though. Your off the hook.??
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David Wilcox K8WPE
ON7DQ Luc
Brien - KE7WB
Paul K7VIQ