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Re: shorted PA on TX, dead SMPSU?

 

reminder: this radio booted up and transmitted before I shorted something near the PA.?
?
update: new SMPSU boards arrived, I tested before installation, as per the wiki article, and they seem fine.
?
I have the SMPSU boards and controls board installed into the main board.?
?
With 7.5v, 200mA current-limited supply, I have zero current before pressing power on switch.
?
Pressing the power switch briefly I get these on the back of the PCB:
?
Board 1:
+12v: 6.0v
Vcc: 0v
adc5v: 0v
pwr_hold: 0.01v
Vin drops to 6.0v?
pwm_5v: 0.01v
pwr_on 0v
?
board 2:
Vdd: 0.41
+12: 6.0v
lin_reg_en: 5.0v
pwm_3v3: 0v
?
With all sub-boards removed, I'm seeing 1.3kOhm gnd->Vcc and 2Ohm (two ohms) gnd->Vdd, so those measurements have got worse.....
?
I then took the SMPSUs out and re-tested, they still pass the tests from the wiki.
?
Any ideas where to look?
Cheers
Dan
?
Re: QMX SMPS issues, and a possible cure

 

To be clear, that spike to 5.7v under worst case 12v supply interruptions would not have damaged anything on the QMX+.
Also, the QMX+ has 470uF on VCC at C107, when I repeat the test with 470uF added the spike is pretty much gone (about 0.1v).
This board would work safely in the QMX+ as originally built.
?
My board did not have any ringing on normal power up, only with extremely short and sharp peterbations on the +12v supply.
It could be that most SMPS designs have some minor trouble here, not a condition that is normally tested for.
?
Just increasing the VCC inductor from 4.7uH to 10uH did not reduce the spike much, it needed the larger 470uF capacitor.
?
Performing these tests where load or supply are interrupted by scraping a wire across a file would likely kill?
a stock QMX, even with the latest firmware.? Also, it would be a difficult test to conduct without risking the STM32F.
This new board has the advantage of being fully testable without being tied to a QMX.
?
Designing a robust feedback loop on a switching power supply from scratch is not trivial.
There's a huge range of fault conditions to account for, and tradeoffs to be made between quick response and undesired ringing.
?
Jerry, KE7ER
?
?
?
On Thu, Apr 3, 2025 at 05:26 PM, Jerry Gaffke wrote:

I loaded up the supply with 50 ohms on 5v, 25 ohms on 3.3v (100ma and 132ma respectively).
When scraping the 12v source to the supply across a file, I saw an occasional triangular peak
on 5v that got up to about 5.7v, the base of that triangle was about 100us.
This was overshoot as the supply recovered from a quick dip in 12v, and only when the?
5v rail didn't go below about 3v.? Scope photo attached.
?
This is exactly the case that was killing QMX's when 12v power was intermittent,?
though I can guarantee the overshoot then was far far worse.? That has mostly
been addressed through firmware changes, though I suspect issues remain.
?
Re: Qmx plus rev 2 not powering up

 

Dear Ludwig
Here follows the next chapters!
I have removed Q102 and Q101 and tested the LIN_REG_EN at the gate of Q101 I got +/-0.6V when pwr button is pressed. So my LIN_REG_EN is being puled down or shorted some where, for sanity I follow the signal pad and I removed the Q110 just in case. I measure again same +/-0.6V.
So now the only connection to the LIN_REG_EN is the STM32, same +/-0.6v on the LIN_REG_EN, seams that the Microcontroler without power is puling the signal down leading it not to start at all.
For sanity I replaced the pull-up resistor R101 and R102 (just in case) same status.?
In my guess I pin pointed this the a problem with the STM32.
SO.... now the hard part... disconnect the SPM32 Pin 88 from the LIN_REG_EN! Done... and confirmed the LIN_REG_EN now measure 12v as VIN. ?
The problem seams to be with the STM32 from the beginning, (So no via issue!!!!Sorry for that one) probably no issue with Q101 and Q102.?
Any way I might be wrong!
Question is what to do next I would like to have the QMX + fully working, some how the STM32 got damaged or came like that.
And thank You so much for the support!
73 Azgael
?
Re: QDX HB Build Notes #qdx #9v #mods

 

You’re on the right track. I suggest you use a very thin layer of thermal compound between the heat sink and flats of the TN0110’s since you’ll be using it in a high-temp environment and a small fan will definitely help.

Tony AC9QY

On Fri, Apr 4, 2025 at 12:27?AM J via <W7LS=[email protected]> wrote:
I have a working QDX, REV-5 pcb, low band and would like to make it more bullet proof with the LTN20069 heatsink and 4 of the TN0110 transistors. I haven't seen any pictures of that. Are there some anywhere? My understanding is that I remove the BS170s and insert the TN0110s, but when folded down, would present their flat faces upward, on which the LTN20069 would lay, complete with a 3mm hole in the center to sandwich it all together. I have a teensie 12v fan to sit on top of the case, with proper holes in it.
?
I need more robustness due to using the QDX in the car, which can get hot. The TN0110s allow for higher voltage use, but I stick to 11.1V batteries because mobile antennas for HF whip around and the swr varies, adding further heat on the finals.
?
Any errors in my plan? I'll post pictures when I'm done.
?
Tnx,
W7LS
Re: #qmx #SSB Firmware beta 1_01_003 release #qmx #ssb

 

Bug in firmware beta 1_01_003 display during Tune SWR:

When I choose Hardware tests and then Tune SWR from the QMX menu, the screen shows a frequency, the tune %, the band, and SWR:. Pressing the left button begins the test and shows the measured SWR value.

The Bug is that the frequency shown on this screen is the frequency that my QMX was tuned to before the test, but this is not the frequency that is transmitted for the test, as confirmed by listening for the tuning signal with another radio.

Turning the TUNE knob while this screen is displayed, either before or after starting the test, updates the display to show the actual frequency used for the test, and allows adjustment of that frequency.

This behavior is the same whether the QMX is in CW, Digi, LSB or USB mode. I did not notice this bug before installing the beta firmware, but I cannot be certain that it wasn't there before.

Peter LaRue
AI7YN
Re: QMX bad RF filter sweep

 

On Fri, Apr 4, 2025 at 04:47 PM, H EA4IIF wrote:
Could the solder joint have gone bad on its own?
Yes, by time, by changing temperature or after some mechanical pressure.
?
And check please also solder joint from T401 towards IC402 pin 7 for QMX Rev. 1 or pin 9 for later revisions.
?
73 Ludwig
Re: QMX bad RF filter sweep

 

Also check that it is still set to the correct band version in system settings?
Re: QMX+ SWR sweeps with SSB firmware?

 

On Fri, Apr 4, 2025 at 04:49 PM, mux_folder2001 wrote:
but it still would not sweep during an SWR sweep but then I noticed that the rig was set on VFO B
The same here.
?
73 Ludwig
Re: QMX+ SWR sweeps with SSB firmware?

 

On Fri, Apr 4, 2025 at 07:31 AM, Roger E Critchlow Jr wrote:
I'm sure there's a reasonable explanation for all this
Roger,
This behavior could result from a cold solder joint in T507 or its associated circuitry.? Temperature can change its connectivity.
Stan
Re: QMX+ SWR Sweeps FW bug report

 

Noted, thanks Tony

73 Hans G0UPL


On Fri, Apr 4, 2025, 16:53 mux_folder2001 via <canthony15=[email protected]> wrote:
I'm not sure if Hans reads every message so I am posting this with its own heading.

I discovered that the SWR sweep test does not actually sweep if the rig is set to use VFO B. Other sweeps seem to work correctly with VFO B selected.

Tony
AD0VC
Re: QMX+ All LPF Sweeps Are Bad #lpf #QMXplus

 

I found the problem.? I was curious about the output power and turned on the power display.? When the display didn't show power or swr, I started troubleshooting that symptom.? It didn't take me long to to track the problem down to a bad solder joint on T507.? Repairing that connection corrected the LPF sweep issue and the swr display.? It makes sense, the measuring circuit was common to all of the LPF paths, thus the across the board impact on the sweeps.
?
Thanks.
?
Andy
WB9YXA?
?
?
Re: All LPF Sweeps Are Bad

 

Nobody else is complaining of the same problem, so, were
I in your shoes, I would look for a systemic problem in the
way I assembled my QMX+.

Several thoughts:

1) perhaps you chronically miscounted the turns on your toroids?
2) perhaps you chronically scrambled toroids when you installed them?
3) there are some test points in the LPF that seem to attract thru hole
capacitor leads (assuming you have a version 2 or older board).
4) bad solder joints on toroid wires are so common as to be a cliche.

About the only thing I can tell you for certain is the radio doesn't
do this when built correctly with good parts.

What I would not do, is transmit to anything other than a dummy load
until this is fixed.

-Chuck Harris, WA3UQV


On Thu, 03 Apr 2025 22:17:52 +0000 "WB9YXA" <ahoffman1@...>
wrote:
I have assembled and have working a QMX+, with one caveat;? all of
the LPF sweeps are bad.
The audio filter sweeps, RF filter sweeps, image sweeps, and SWR
sweeps look reasonable, although on a couple of bands the SWR sweeps
aren't flat across the entire bandwidth swept, but were always good
in the ham band frequencies.? The I/Q sweeps all looked good except
for 160 Meters where the phases were in sync for some reason.? Not
really a problem for me, I don't own that much wire. Here's the real
problem.? All of the LPF sweeps are bad.? For example: 0 ?|
* .* ?* ?* ?* .* ?* ?* ? ? . ? ? ? * ?* .* ?* ?* ? ?. ?* ?* ?* ? . |
* ? ?* ?* .* ?* ?* ?* .* ?* ?* ?* ?* ? ?* ?* ?* .* ?* ?* ? ?* ?* ?*
* ?*. | ?* ?* ** * .* ?* ?* ?* .* ** ** ** ** ** ** * ?* .* ?* ?* ?*
** * ?* ?* ?** | ** ** ** **.* ?* ?* ?* ** ** ** ** ** ** ** ** * .*
* ** ** ** * ?* ?* * * | ** ** ** **.** * ** ** ** ** ** ** ** ** **
** **.* ** ** ** ** ** * ** * * | ** ** ** **.***|*** ** ** ** ** **
** ** ** ** *** *** ** ** ** **** ** * * | ** ** ** *** **|** *** **
** ** ** ** ** ** *** ** *** ** ** ** *** *** * * | ** ** *** **
**|** ** ** ** ** *** ** ** *** ** ** ** ** *** *** ** ** ** * | *
*** *** ** **|** ** ** ** ** ** **.*** *** ** ** ** ** *** *** ** **
** * | * * ?* ?* ?* **|** ** ** * ?* ?* ?* .* ?* ?* ?* ** ** ** * ?*.
* ?* ** ** * | * * ?* ?* ?* ?*|* ?* ?*. * ?* ?* ?* .* ?* ?* ?* ?* *
* ?* ?*. * ?* * ?* ?* | * * ?* ?* ?* ? |* ?* ?*. * ?* ?* ?* .* ?* ?*
* ?* * ?* ?* ?*. * ?* * ?* ?* |* ?* ?* ?* ?* ? | ? * ?*. * ?* ?* ?*
.* ?* ?* ?* ?. ? ?* ?* ?*. * ? ?* ?* ?* |* ?* ?* ?* ?. ? | ? ? ?*. *
* ?* ?* .* ?* ?* ?* ?. ? ?* ?* ?*. * ? ? ? * ?* |* ?* ?* ?* ?. ? |
?*. * ?* ?* ?* .* ?* ?* ? ? . ? ?* ?* ?*. * ? ? ? * ?* |* ?* ?* ?*
. ? | ? ? ? . ? ?* ?* ?* .* ?* ?* ? ? . ? ? ? * ?*. ? ? ? ? * ?* |*
* ?* ? ? . ? | ? ? ? . ? ? ? ? ?* .* ?* ? ? ? ?. ? ? ? ? ?*.
?* |* ? ? * ? ? . ? | ? ? ? . ? ? ? ? ? ?. ? * ? ? ? ?. ? ? ? ? ?*.
? ? ? ? ?* |* ? ? ? ? ? . ? | ? ? ? . ? ? ? ? ? ?. ? ? ? ? ? ?.
? ? . ? ? ? ? ? ?. |* ? ? ? ? ? . ? | ? ? ? . ? ? ? ? ? ?.
?. ? ? ? ? ? . ? ? ? ? ? ?. -8 |* ? ? ? ? ? . ? | ? ? ? .
. ? ? ? ? ? ?. ? ? ? ? ? . ? ? ? ? ? ?.
----------------------------------------------------------------------------
6 ? ? ? ? ? 9 ? ? ? ? ? 12 ? ? ? ? ? 15 ? ? ? ? ?18 ? ? ? ? ? 21 0
|. ? ? ? ?*. * ?* ? ? . ? ? ? ? . ? ? ? ? . ? ? ? ? ?. ? ? ? ? .
? . |.* ? ? ? *. * ?* ?* ?. ? ?* ?* . ? ? * ?*. * ? ? ? *. * ? ? ? *
?* ? ? ?.* |.* ?* ? ?** * ?* ?* ?. * ?* ?* .* ? ?* ?*. * ?* ? ?*. *
* ? ?* ?* ? ?* .* |.* ?* ?* ** * ?* ?* ?. * ?* ?* .* ? ?* ?*. * ?*
*. * ?* ? ?* ?* ?* * .* |** ** ** ** **** ** ** ** * ?* ** ? ?* ?*. *
?* ? ?*. * ?* * ?* ?* ?* **.* |** ** ** ** **** ** ** ** * ?* ** **
** *.** ** ** ** * ** ** ** * ** **.* |** ** ** ***|*** ** ** ** ****
** ** ** *.** ** ** ** * ** ** ** * ** **.* |** ** ** ***|** *** **
** **** ** ** *** *** ** ** **** ** ** **** ** **.** |* *** *** .*|**
*** ** *** *** ** ** *** *** ** ** *** *** ** *** *** *** * |. ***
*** .*|** ** *** *** ** *** *** ** ** *** *** ** *** ***.** *** *** *
|. ** ** * .*| ? * ?*** *** ** ** **** ** ** *** *** ** ** ****.**
*** *** ** |. * ?* ?* .*| ? * ?* ** ?* ** ** ** * ?* * ?** ** * .* *
* ?*.** ** * ?* * |. * ?* ?* .*| ? * ?* .* ?* ** *. * ?* ?* * ?* ?*
* .* * ?* ?*. * * ?* ?* * |. * ?* ?* . | ? * ?* .* ?* ? ?*. * ?* ?* *
?* ?* ?* .* * ?* ?*. * * ?* ?* * |. * ?* ?* . | ? * ?* .* ?* ? ?*. *
* ? ?* ?* ?* ?* . ?* ?* ?*. * * ?* ?* |. * ?* ?* . | ? ? ?* .* ?*
*. * ?* ? ?. ?* ?* ?* . ?* ?* ?*. ? * ?* ?* |. * ?* ?* . | ? ? ?* .*
* ? ?*. * ?* ? ?. ?* ?* ?* . ? ? * ?*. ? * ?* ?. |. ? ?* ?* . |
* .* ? ? ? *. * ?* ? ?. ?* ?* ?* . ? ? * ?*. ? ? ?* ?. |. ? ?* ? ?. |
? ? ?* .* ? ? ? ?. * ?* ? ?. ? ? * ?* . ? ? * ?*. ? ? ?* ?. |.
. | ? ? ? ?.* ? ? ? ?. * ? ? ? . ? ? * ? ?. ? ? * ? . ? ? ?* ?. -7
|. ? ? ? ? . | ? ? ? ?.* ? ? ? ?. ? ? ? ? . ? ? * ? ?. ? ? ? ? .
* ?.
----------------------------------------------------------------------------
16 ? ? ? ?24 ? ? ? ? 32 ? ? ? ?40 ? ? ? ?48 ? ? ? ? 56 ? ? ? ?64
?72 All of the other bands exhibit a similar pattern. I tried
looking for something common to all of the filters, but nothing I
came up with made any sense given that the other sweeps were
'normal'. Since everything looked OK except for the LPF sweeps, I
decided to perform a smoke test.? I hooked it up to EFHW at 20 feet
and worked Oklahoma on 40 Meters FT8, so the transceiver is working.
I don't have the necessary test equipment to check the spectral
purity of the output signal so I'm hesitant to continue using it on
the air until I resolve this problem. I tried searching for a
solution both here and with Google, read a lot about fixing issues I
don't have but nothing that pointed me in the right direction. Thanks
all for the great ideas I'm about to receive. Andy WB9YXA
QMX+ SWR Sweeps FW bug report

 

开云体育

I'm not sure if Hans reads every message so I am posting this with its own heading.

I discovered that the SWR sweep test does not actually sweep if the rig is set to use VFO B. Other sweeps seem to work correctly with VFO B selected.

Tony
AD0VC
Re: QMX+ SWR sweeps with SSB firmware?

 

开云体育

I tried switching back to 1.027 but it still would not sweep during an SWR sweep but then I noticed that the rig was set on VFO B! I switched back to VFO A and it sweeps correctly now!

That seems like a bug to me because the sweeps for everything else work with VFO B, just not the SWR sweep.

Whew.?

Tony
AD0VC

From: [email protected] <[email protected]> on behalf of mux_folder2001 via groups.io <canthony15@...>
Sent: Friday, April 4, 2025 8:29 AM
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] QMX+ SWR sweeps with SSB firmware?
?
I can tell it is not sweeping when doing an SWR sweep because the external SWR meter holds steady while connected to my 6BTV. If I do an LPF sweep, the external meter swings all over the place as it sweeps.

Tony
From: [email protected] <[email protected]> on behalf of Chris <chris.rowland@...>
Sent: Friday, April 4, 2025 2:26 AM
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] QMX+ SWR sweeps with SSB firmware?
?
On Thu, Apr 3, 2025 at 02:00 PM, mux_folder2001 wrote:
It is clearly not actually sweeping for some reason.
How can you tell?? You need to be monitoring the frequency to see if it is sweeping.
?
Chris, G5CTH
Re: QMX bad RF filter sweep

 

Thanks for the reply! Could the solder joint have gone bad on its own? As I stated, it was working perfectly fine until about 1-2 weeks ago. I'll test it this evening though
Re: QMX+ SWR sweeps with SSB firmware?

 

Okay, I am running? and have run the calibrations, but haven't started adjusting band settings or attempting any SSB yet.? ?This is a QMX+ connected to a mag loop antenna.
?
Keying CW on 40m, I got SWR protected, so I Menued into Hardware Tests > Tune SWR and and tuned.? The SWR reported is flickering around 1.7 and 1.8, which shouldn't trigger SWR protect.? ?Ah, but I'm connected to a mag loop antenna, and the SWR reported continues to flicker around 1.7 and 1.8 as I tune the loop all the way to 10m and back again.? The loop tuning is working, in receive I can hear the loop resonance moving as a peak in received noise.
?
So I connect the serial monitor, go to the diagnostics page, and T on 40m.? It reports an SWR of 1.2-1.3.??
?
Then I go back to the QMX menu to Tune SWR, and now it reports 10.? But I'm no longer sure what frequency the radio and the antenna are tuned to at this point.
?
Then I turn the radio off for an hour.
?
And when I come back I open the Serial Monitor, navigate to Hardware tests > SWR scan.? It scans from 3MHz to 9MHz and reports 10 for every frequency.? (But I realize later that I might have overlooked a dip at the resonant frequency, they can be easy to miss.)? I go back to the radio and tune the mag loop for maximum received noise.? I do another SWR scan it now reports 1.95 to 2.1 for every frequency in the scan.??
?
I go back to Hardware Tests > Tune SWR and it now flickers around 1.9-2.0, but the SWR now responds when I tune the mag loop, and I'm able to tune it down to 1.33.? But I get SWR protected again before I can send my whole callsign.
?
I begin to feel like an unreliable witness at this point.? I go back to Hardware tests > SWR scan.? It draws 10 except for a small spike down around 7.? I peak the antenna to 7025kHz and scan again, now I get an obvious and substantial spike down to 1.5 SWR.
?
I'm sure there's a reasonable explanation for all this.
?
-- 73 -- rec -- ad5dz --
Re: QMX+ SWR sweeps with SSB firmware?

 

开云体育

I can tell it is not sweeping when doing an SWR sweep because the external SWR meter holds steady while connected to my 6BTV. If I do an LPF sweep, the external meter swings all over the place as it sweeps.

Tony

From: [email protected] <[email protected]> on behalf of Chris <chris.rowland@...>
Sent: Friday, April 4, 2025 2:26 AM
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] QMX+ SWR sweeps with SSB firmware?
?
On Thu, Apr 3, 2025 at 02:00 PM, mux_folder2001 wrote:
It is clearly not actually sweeping for some reason.
How can you tell?? You need to be monitoring the frequency to see if it is sweeping.
?
Chris, G5CTH
Re: QMX bad RF filter sweep

 

Hi Hector,
?
alle the values are much to low, around -40 dB for the (real) peaks. It looks like a bad connection in the RX path. Please check solder joint of L401 towards IC402 pin9 for QMX Rev. 1 or towards "RX_IN" for later revisions.
?
73 Ludwig
Re: QCX+ Menu 8.5 Ref frq

 

I like to participate in the ARRL FMT runs.?So . . .?
?
I have investigated frequency response accuracy of my High and Low band QDX's, my HB QMX and my QMX+.
Don't have a QCX so can't speak direct to that model.?
?
All have been within a hertz or two or better, right out off the assembly bench when checked with 2 different Leo Bodnar Precision GPS Disciplined Clocks units.? I have found that I can tweak the TCXO system setting by a few hertz , from as little as +2 to a high of +10 on one band for best frequency response.? Be advised that the best delta will vary a bit ( maybe 0.5 Hz worst case) from band to band in a given radio.?

I use FLdigi on the Frequency Measurement Test OpMode. Found it to be quite useful and instructive in showing things like warm-up drift, probable doppler shifts of received over the air signals and subtle changes ( hundredths (0.0x Hz) or less of shifts) just sitting on the bench in response to my heat or AC cutting on and off.? And there will be a bit of offset needed to completely correct for the FMT modem response on the particular computer on which you are running the FLDigi program.?
?
Now having said that, I have spent hours measuring and analyzing over the air received WWV and CHU signals and its a rare band on a rare day & time, on a rare day of overall radio 'quiet' when the signals are rock solid as seen in FLDigi.? You have to be located inside the first skip zone of the transmitters for consistency in that.?
?
And I'll bet for actual Ham Radio Operations, all the Q's will be just fine as assembled.?
?
There is LOTS of interesting information, articles and How-To's for Frequency Measurement Testing with relatively simple and inexpensive methods these days.? ?Just give it a Google and wade in.? There's even a FMT-NUTS group.io.?
?
GREG? KI4NVX
Re: QCX+ Menu 8.5 Ref frq

 

Hi Pierre. Since you indicated a reference frequency of 25 MHz, Bruce correctly assumes you have the TCXO option installed in which case you shouldn’t need to worry about calibration. If you don’t have the TCXO installed then the reference frequency is 27 MHz and your procedure should work ok to get close however getting exact zero beat may be difficult since the audio rolls off at the low end.?

Good luck ….73 …. Ron

On Thu, Apr 3, 2025 at 20:41 Pierre - FK8IH via <jb.gallauziaux=[email protected]> wrote:
I would like to know if I can apply the following procedure to calibrate the Ref frq without GPS?
Using a QCX+ 20M Band I would go to WWV 15MHz and read precisely the frequency for a zero beat. If I read 15.003.00 could I modify menu 8.5 to read 25.005.000 with the TCXO and have a more precise QCX+?
73 - Pierre - FK8IH
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