On Thu, Mar 27, 2025 at 08:14 PM, Stan Dye wrote:
440mA and 340mA are way too high, indicating something pulling down on the 3.3V power supply.
Oops, I wrote too quickly again.? In your case it could also be something else.? A voltage very near your 7V input should be appearing at VI of IC101, rather than the 5V that you see.?? Check carefully the 12V input as it appears on the 3.3V SMPS.? Has it dropped to 5V at that point (being pulled down somewhere in the interconnect)?? Or is it dropping from 7V to 5V across Q102?? That measurement can give you a hint, if you don't find the error doing the independent SMPS tests.? I suspect (based on your measurement of LIN_REG_EN) that you will see it dropped to 5V at the input of Q102, which would mean that the 12V bus is not getting cleanly to your 3.3V SMPS via the connectors.
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Good luck, Stan.
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QMX+ high pitch noise on power. Now dead.
I was just building a microphone for the qmx and then I plugged it into my power supply to test it. I on purpose to turn the voltage down from 13.8 and then turn it on. It worked fine but I needed to turn it off and back on again for it to connect to my computer. I turned it off and then when I tried to turn it back on it was a high-pitched noise for about half a second in the screen backlight turned on and then it turned off and now shows no signs of Life except power draw when I press the button.
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Re: QMX+ SSB audio distorted on one band only
Stan,
This seems to have worked for me. Thank you! It took some time playing with the limit/center values to fix 17,15,12, and 10 meters. 160 and 11 are still broken but I don't use either of them.?
Tony
AD0VC
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On Thu, Mar 27, 2025 at 05:19 PM, Ellis Simon GM4GZW wrote:
The phase calibration sweep for 20M also looks odd and is different to the others which are all nice curves
Based on some experimentation with some similar phase calibration results on a couple of bands on two of my QMX, it appears to me that when the phase distortion curve is started, but not completed, then the audio gets distorted.? And the lower the value it
stops at, the worse the distortion.? In your example, the curve of values only goes to about a value of 600 on the horizontal DAC axis.? So my theory is that whenever your voice waveform has an amplitude that results in any DAC value of over 600, there is
not a proper result stored in the calibration table for those values, and 'bad stuff happens', resulting in distorted audio.
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So (if my theory is correct, and it seems to have worked on my 2 QMX), if you can get the calibration to put in measured phase values across the whole range of the DAC (about 2600 for 12V builds and 2000 for 9V builds), then the resulting voice quality
is good, even if the graph looks uneven or strange.
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I was able to get my calibration to finish on the 'bad' bands by adjusting (as others have noted) the "Frequency min" and/or "Frequency center" in the band configuration screen.? For some reason these do affect the way the phase calibration runs.? I had
to play with different values in one or both of those settings, but without too much trouble got all of the bands to have "complete" phase distortion curves.? The 'curves' were not always pretty, but I don't think that's so much the issue as having data initialized
for the full range of DAC values? that will be used (based on the input voltage and drive level, both of which Hans pointed out need to be set before calibrating).
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After I changed the band config settings for calibration, I restored the band settings to their original values so the other diagnostic sweeps would still function in the same way, and so my default 'center frequency' would be what I want on each band.?
[These settings don't affect normal transmit/receive operation, we just needed to 'seed' them differently to get completion of the calibration table.]
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I hope this is helpful to someone, and maybe someone can corroborate my theory on getting rid of the distorted audio....
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Stan KC7XE
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Sorry for my previous message (now deleted).?? Ludwig's value was correct, as always.
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After removing the SMPS cards to test them, as Ludwig has recommended, also measure the resistance between Vcc and GND, and Vdd and GND on the main board, which should be a few k-ohms each.? And also measure Vcc to Vdd, and 12V to Vcc and Vdd - each of these should have a very high resistance, in the mega-ohm range.? You likely have a short or a failed component somewhere - and the first place to check is the voltage rails, because if that is where the short is, it can continue to cause additional failures.
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For all further testing, until after a successful power-on is completed, please set a current? limit on your supply to about 250mA if possible.? Without a current limit, some types of issues can fuse your SMPS protection diodes or damage a main board component.? I hope your new 3.3V SMPS is still ok.? 440mA and 340mA are way too high, indicating something pulling down on the 3.3V power supply.
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Stan KC7XE
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Re: QMX+ Right button Diagnosing as "on"
I'm very glad you got it working!
I'm very sad it failed again.
When pushing the card into the bottom enclosure, we almost always 'torque' the front panel a bit.? This could cause the connectors to seat differently, or a cold solder joint to open up.? So it may be worth a few tries of repositioning the front panel onto its connectors (if you haven't done that already) to see if the problem will go away.
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And if you are in the USA and send it to Jeff W1NC, you will get it back and fully operational much faster and cheaper than ordering a pre-built kit.
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Stan KC7XE
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Re: SSB audio distortion #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
On Thu, Mar 27, 2025 at 08:34 AM, Mehmet Dinch wrote:
The plot doesnt look any better..
Try several different settings of either 'Frequency min.' and/or 'Frequency center'.? I was able to (with a few trials) get the plot to complete out to the full x-axis range.? I think that a 'complete table' is the issue for distorted audio, rather than the shape of the plot.? A couple of my band plots have very strange variations like that, but do not noticeably distort the audio since I got the plot to complete all the way across.
?
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Stan KC7XE
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Re: QMX+ SSB audio distorted on one band only
On Thu, Mar 27, 2025 at 05:19 PM, Ellis Simon GM4GZW wrote:
The phase calibration sweep for 20M also looks odd and is different to the others which are all nice curves
Based on some experimentation with some similar phase calibration results on a couple of bands on two of my QMX, it appears to me that when the phase distortion curve is started, but not completed, then the audio gets distorted.? And the lower the value it stops at, the worse the distortion.? In your example, the curve of values only goes to about a value of 600 on the horizontal DAC axis.? So my theory is that whenever your voice waveform has an amplitude that results in any DAC value of over 600, there is not a proper result stored in the calibration table for those values, and 'bad stuff happens', resulting in distorted audio.
?
So (if my theory is correct, and it seems to have worked on my 2 QMX), if you can get the calibration to put in measured phase values across the whole range of the DAC (about 2600 for 12V builds and 2000 for 9V builds), then the resulting voice quality is good, even if the graph looks uneven or strange.
?
I was able to get my calibration to finish on the 'bad' bands by adjusting (as others have noted) the "Frequency min" and/or "Frequency center" in the band configuration screen.? For some reason these do affect the way the phase calibration runs.? I had to play with different values in one or both of those settings, but without too much trouble got all of the bands to have "complete" phase distortion curves.? The 'curves' were not always pretty, but I don't think that's so much the issue as having data initialized for the full range of DAC values? that will be used (based on the input voltage and drive level, both of which Hans pointed out need to be set before calibrating).
?
After I changed the band config settings for calibration, I restored the band settings to their original values so the other diagnostic sweeps would still function in the same way, and so my default 'center frequency' would be what I want on each band.? [These settings don't affect normal transmit/receive operation, we just needed to 'seed' them differently to get completion of the calibration table.]
?
I hope this is helpful to someone, and maybe someone can corroborate my theory on getting rid of the distorted audio....
?
Stan KC7XE
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Re: QMX+ SSB audio distorted on one band only
Ellis
?
Distortion on one band only could be RF getting into audio. See if same thing happens when transmitting into dummy load. And maybe an external signal report.?
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Curt
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Thanks everyone. I had done everything correctly but in my excitement to try out the rig, not fitted the link in JP501. Obviously skimmed over page 36 as well !
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Jeremy,
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IC101 VI should be at least 5.3 V + 0.6 V (elevated GND of IC101). Your 5.0 V is not enough for 3.3 V output.
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Without a running controller LIN_REG_EN is made by a voltage devider, 0.5 * "+12V".? Your 5.1 V is wrong. Please consult schematics page 1 to see where to check.
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73 Ludwig
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Re: QMX+ Strange Audio Artifact - Help, Please...
Tell it to enjoy it's holiday.? I have plans on its return.
On March 27, 2025, at 18:11, "Jeffrey W Moore via groups.io" <jeffreymoore@...> wrote: I was hoping for a simple solution for you. ?The possibilities are many now. ?So it’s hard to know what to tackle next without scoping some of the signals. ?
if you do send it for a Cape Cod vacation, it will be short. ?I’ve almost cleared my backlog after a weeklong vacation. ?Hi hi
?
--
73
Jeff Moore
W1NC
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QMX+ SSB audio distorted on one band only
Hi,
I installed the 1_01_003 beta firmware yesterday and I am amazed at how it has transformed my QMX+ (rev 2 board).
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I am, however, perplexed at the fact that the SSB audio is distorted (on another receiver) only on 20M. This only occurred after calibration and the audio becomes absolutely clear again after disabling the phase predistortion. All other bands have good audio with and without predistortion, and the RF output is within normal limits on all bands, although 20M is a little lower than others at about 3W. I am using a 12V stabilised PSU and a good dummy load, via a Bird isolator, giving me a solid signal into my receiver.
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Trying to think of an explanation made me consider that the LPF used for 20M (LPF 3) may not present a good load to the PA, so I looked at the LPF sweep using PuTTY. Here is the sweep for 20M:
The 14MHz line is in a less than ideal part of the curve, whereas the bands which share this LPF are better placed. Is this significant?
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The phase calibration sweep for 20M also looks odd and is different to the others which are all nice curves (except 160M which sounds fine!):
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This is the 20M USB IMD sync optimisation curve, the title of which has been overwritten by the asterisks of the curve.
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The 20M USB curve looks identical:
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Here is the adjacent band 30M curve for comparison:
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Everything on the board looks good and the radio otherwise works perfectly. I am perplexed at why only one band is distorted (it really is unreadable) yet 160m, which has similar calibration curves but a great looking LPF, Sounds OK.
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Any ideas?
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The simple answer is to switch off predistortion, but that doesn't solve the problem!
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73
?
Ellis
GM4GZW
?
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Re: SSB audio distortion #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
On Fri, Mar 28, 2025 at 12:44 AM, Mehmet Dinch wrote:
Thanks for sharing your settings.
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Are these setting post calibration?
?
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Post calibration - which was run without any other adjustments.
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Re: QMX+ Right button Diagnosing as "on"
Thanks, Stan. I got a nice thick tip and reflowed all of the connections on the display, and the header pins for the display. Powered it up and there was ZERO phantom button pushing going on. I used it for several minutes like this, ran the GPS diagnostic screen, went through several menus, configured a bunch of stuff... it worked PERFECTLY! Slid the bottom of the case back on and powered it up and I see the issue again. I've looked VERY closely to make sure nothing is shorting on the case. Even after removing the board from the case it still happens again. I'll probably just hang this one on the shelf and order an assembled kit. Thanks.?
Brandon
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
Hector, maybe you are just noticing them more because in SSB mode your receiver bandwidth is a lot wider.
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73, Dan - W2DLC
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I just finished building a QDX board version 3 with the latest 1.10 firmware installed and have been testing it. I built it for 9v operation and am using a variable bench power supply to test it. I have made a few FT8 QSOs on both 40m and 20m, I am noticing the power starts out at about 4w and slowly drops to about 2w by the end of the FT8 transmission cycle. The voltage from the power supply is a rock solid 9v. The current draw on transmit starts at about 1.02 amps and drops to about .4 - .5 amps by the end of the transmission cycle. Is this normal and if not, what should I be looking at?
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73 Doug WB5WRC
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I recently finished my first build of the QMX and can't get it to power up properly. At first when I pressed the left encoder, the power consumption went up to 440 mA and then back down when the encoder was released. After some inspection I thought that I had blown Q101 because it was getting hot with the left encoder pressed. I replaced it and my consumption when down to 340 mA but it would still not power on.
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Thinking it was a problem with the power board I ordered a new 3.3V power board and replaced it. I still get 340 mA when the left encoder is pressed. With a 7.0V supply I am getting the following voltages with the left encoder pressed.
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+12V: 7.0V
LIN_REG_EN: 5.1V
VDD: 0.2V
IC101 VI: 5.0V
IC101 VO: 1.2V
IC101 GND: 0.5V
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Would appreciate some thoughts if anyone has had a similar problem or might know what is going on
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Thanks,
Jeremy Goates
KK7QVY
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
Hi! Has anyone experienced an increase in birdies and/or decrease of rx sensitivity?
Maybe its my AGC settings but I get a lot of birdies and some of them are very annoying, maybe they were already there but it seems to me that they increased since the update.
About the birdies, I read they should get better as the firmware gets updated, but I wonder if its just my device. The sensitivity thing could be too the AGC but Im not really sure. It could also be the birdies since some of them are near the signals im tunning in. This is all comparing it to a chinese uSDX and previous QMX CW operation.
I updated to the 1.01.003 and so far everything is okay besides that. SSB tx works really great, specially the CESSB.
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73, Hector-EA4IIF
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Re: QMX+ Strange Audio Artifact - Help, Please...
I was hoping for a simple solution for you. ?The possibilities are many now. ?So it’s hard to know what to tackle next without scoping some of the signals. ?
if you do send it for a Cape Cod vacation, it will be short. ?I’ve almost cleared my backlog after a weeklong vacation. ?Hi hi
?
--
73
Jeff Moore
W1NC
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Re: QMX+ Strange Audio Artifact - Help, Please...
My experience with Jeff was very positive. ?
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Show quoted text
On Mar 27, 2025, at 1:18?PM, Jim Bennett / K7TXA via groups.io <w6jhb@...> wrote:
Took a deep breath and removed C504. It measures about 500 uf so this cap is fine. No problem re-installing it. Other than my shaky hands!
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I did find an interesting thing while doing the testing. I had been using an Astron VS-35M p.s. in the shack into a boost-buck device set to exactly 12 v. It also shows current but I've found that to be completely bogus. Today I took the QMX+ to the garage workbench and connected it to my benchtop p.s. which is a lot more accurate than the boost-buck and is capable of current and voltage limiting. With it set at 12.0 v I did a key down on the QMX+. The output voltage stayed at 12.0 or so, but the constant current light and constant voltage light both flickered - and at the exact tempo as that machine gun sound on my headphones. Strange. I unhooked the radio and replaced it with another QMX+ that I built last year that works perfectly. No machine gun audio on key down and no flashing lights on that bench p.s.
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At this point I may have reached the upper limit of my debugging ability. Perhaps the only other thing I could try would be to remove D502 and test it, although it is a lot smaller than that tantalum cap and might prove tricky for me to attack.
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If you guys think it's worth testing that thing I'll give it a try. Or if there is something else that is within my capabilities... Otherwise it might be headed to Jeff for a New England vacation.
--
Jim / K7TXA
Eagle, ID
SKCC 10447T
BUG 301
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Leland Lannoye, W9HIF
Brandon Mercer
Daniel Conklin