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Date
Board revision

 

Hi,
?
I've just ordered a QMX+. I want to print the assembly manual out. I'm assuming it'll be a Rev 3 PCB but I'm wondering if I should wait until the kit arrives to be sure and not 'waste' paper and ink?

Thanks
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Mike
Re: QMX+ SSB audio distorted on one band only

 

Update.
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After a lot of fiddling with the 20m band edges I ended up with this:
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Which leads to this:
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Which seems to have cured the distortion.
?
I have no understanding of what the frequency numbers represent as changing them did not seem to change any of the diagnostic filter sweep widths. I found very little improvement with changing the minimum frequency or the centre frequency. The best change involved increasing the maximum frequency and placing the centre frequency near the top of the range, as you see from my 20M column.
?
I hope that this may help someone else. Thanks for your help with this.
?
73
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Ellis
GM4GZW
Re: Power Failure on New Factory-Assembled QMX+

 

Many thanks, Don and Daniel.? With great sadness I have opened a support ticket, but I agree that there's not really another option for me.?
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Again my thanks,
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Tim Ei2KA
Re: QMX+ high pitch noise on power. Now dead.

 

Where is D110 on the qmx board? I can try to check its state.


On Fri, Mar 28, 2025, 6:17?AM Nico Smith via <nicosmith873=[email protected]> wrote:

I turned it off with the QMX power switch. Earlier today it was exposed to more voltage for a short period of time but it was still working fine after that. I'm not very good at reading schematics but what measurements should I do?


On Thu, Mar 27, 2025, 11:44?PM Stan Dye via <standye=[email protected]> wrote:
When you turned it off and back on, did you do it with the switch on your power supply, or with the QMX front button?
?
Your symptoms are that you now have an internal power fault, which prevents the QMX+ from powering on.
One possibility:? If the input voltage from your power supply ever exceeded 14V, for more than a second or two, even with the QMX+ turned off, or if there was a high voltage transient from the power supply, it may have fused the input protection TVS diode (D110).? 13.8V on continuously for a period of time possibly could also damage that diode, which starts conducting somewhere between 13V and 14V.? There are of course other possibilities, only measurements will tell.
?
It will be best to turn down your voltage to about 7V and set a 250mA current limit while diagnosing this, if possible, to avoid any new faults.
Stan KC7XE
Re: QMX+ high pitch noise on power. Now dead.

 

I turned it off with the QMX power switch. Earlier today it was exposed to more voltage for a short period of time but it was still working fine after that. I'm not very good at reading schematics but what measurements should I do?


On Thu, Mar 27, 2025, 11:44?PM Stan Dye via <standye=[email protected]> wrote:
When you turned it off and back on, did you do it with the switch on your power supply, or with the QMX front button?
?
Your symptoms are that you now have an internal power fault, which prevents the QMX+ from powering on.
One possibility:? If the input voltage from your power supply ever exceeded 14V, for more than a second or two, even with the QMX+ turned off, or if there was a high voltage transient from the power supply, it may have fused the input protection TVS diode (D110).? 13.8V on continuously for a period of time possibly could also damage that diode, which starts conducting somewhere between 13V and 14V.? There are of course other possibilities, only measurements will tell.
?
It will be best to turn down your voltage to about 7V and set a 250mA current limit while diagnosing this, if possible, to avoid any new faults.
Stan KC7XE
Re: SSB audio distortion #qmx #SSB Firmware beta 1_01_003 release #qmx #ssb

 

Hi Stan,
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Thanks for the tip.
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I did have a go at messing around with the band config for 20m but I was trying to get a plot similar to the examples rather than aiming to get a complete run.
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Could you share your band config please as a guide. I know that mine will be different..
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Cheers,
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Mel. M0KMD.
Re: QMX+ SSB audio distorted on one band only

 

Stan,
Many thanks for this. It makes complete sense in my head. Can you give me a clue as to which direction you changed the band sweep values?
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Ellis
Re: QMX+ SSB audio distorted on one band only

 

Thanks Curt.?

it was all on dummy load. I’ve not transmitted SSB on an antenna yet!
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Ellis
Re: QMX won’t power up

 

Sorry. Most importantly. No heat. No smoke.?
QMX won’t power up

 

Hello. I was using my QMX on 40m and 20m FT8 with a known good antenna and computer connection, successful QSOs, and no SWR lock outs or other signs of issue.?

The QMX screen went to all backlight with no LCD characters displayed for 1-2 sec and then went to a mix of full block LCD and some apparently random characters. Screen has no obvious physical damage. I was not transmitting at the time.?

I attempted basic battery / power troubleshooting to no avail. With a known good power source, it will not power on. Confirmed it is not limited to a screen issue, there is no RX as tested with audio output.?

What other troubleshooting is recommended? I’m ok with basic electrical repair, but don’t see myself doing and surface mount repairs. And I’m hoping there’s a possible test to rule out failed components and possibly an easy fix.?

I have explored the archives and didn’t see a similar problem noted. Thanks for any help.?
Re: Difficulty after loading ssb firmware beta 1-01-03 on QMX+

 

In my case it seems that editing the tcxo down 2 Hz causes the audio dropout. Returning to 25Mhz instantly restored things !! Yes I am running the SSB beta 1-00-03 firmware.
de VK6XT?
Re: QMX+ loss of CAT after "S"

 

Good chance the SWR was accompanied with common mode current on the connection(s) to the PC which could cause connection loss (and worse)
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Sort the antenna and ‘ferrite up’
Re: QMX+ loss of CAT after "S"

 

The S can re removed, and transmission resumed by visiting a menu, AIUI any menu.? the same thing may work for restoring CAT.?
Chris, G5CTH
QMX+ loses audio.

 

After a factory reset my QMX+ runs fine for hours running wspr. If I attempt to change parameters through the front panel...turn on clock...dot delim etc it will lose audio connectivity to wsjt and through headphones. Factory reset and reboot wsjt does restore things back to normal. Perhaps I should not try to customise anything whilst under control of WSJT?
Re: #qmx #SSB Firmware beta 1_01_003 release #qmx #ssb

 

Thank you Stan! I did as you said and now I have Terminal and my PTT is enebled!
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BR/Sergey
UB3AZK
Re: Difficulty after loading ssb firmware beta 1-01-03 on QMX+

 

I have exactly the same problem after updating the software, the radio stopped receiving, I can hear noise.
QMX+ loss of CAT after "S"

 

My radio generated an SWR alarm after WSJT-x briefly transmitted on one of the "receive only" bands during band hopping. Whilst this is a very desirable traits, I discovered that it was no longer possible to QSY via CAT. Power off reset cleared the condition.
de VK6XT.
Re: Difficulty after loading ssb firmware beta 1-01-03 on QMX+

 

I am having the same problems
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de VK6XT?
Re: Toroids: Do I have these sorted correctly? #QMXplus

 

Yes, they are also a slightly different shape.? And made with a completely different manufacturing process and material, a ferrite blend, rather than the powdered iron typically used in the other cores.
Re: QMX+ high pitch noise on power. Now dead.

 

When you turned it off and back on, did you do it with the switch on your power supply, or with the QMX front button?
?
Your symptoms are that you now have an internal power fault, which prevents the QMX+ from powering on.
One possibility:? If the input voltage from your power supply ever exceeded 14V, for more than a second or two, even with the QMX+ turned off, or if there was a high voltage transient from the power supply, it may have fused the input protection TVS diode (D110).? 13.8V on continuously for a period of time possibly could also damage that diode, which starts conducting somewhere between 13V and 14V.? There are of course other possibilities, only measurements will tell.
?
It will be best to turn down your voltage to about 7V and set a 250mA current limit while diagnosing this, if possible, to avoid any new faults.
Stan KC7XE
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