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QMX mid band not being seen by my computer on initial power up

 

Hi All,
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I just recently finished my QMX mid band kit and on powering up, my computer does not see any usb device. I have tried a computer running Windows 10 and another running Linux.
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I have tried multiple combinations of plugging or having the device unplugged before power on.
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I have been using a voltage and current limiter with a battery pictured below, limiting voltage to 7V then 9V (to see if that would make a difference) and limiting current to 250 mA.
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In the pictures, you can see the device off then when I turn it on, the V out goes down slightly and there is a 170 mA current draw.
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Thanks all for any suggestions,
Andrew
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Andrew,? All current QMXs already come with the software installed, so will be seen as a com device, and USB audio, not as USB storage. More concerning is that you aren't seeing anything on the LCD. Have you adjusted the LCD contrast pot?
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73, Dan - W2DLC
 

Correction: QMX+ comes with firmware installed. QMX comes without firmware installed and will show up as a USB Flash drive ready to copy in the firmware file. All assembled radios of all types always have the latest production firmware tested and adjusted.?

73 Hans G0UPL


On Sun, Apr 13, 2025, 14:25 Daniel Conklin via <danconklin2=[email protected]> wrote:
Andrew,? All current QMXs already come with the software installed, so will be seen as a com device, and USB audio, not as USB storage. More concerning is that you aren't seeing anything on the LCD. Have you adjusted the LCD contrast pot?
--
73, Dan - W2DLC
 

Hi Dan,
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Thanks for your reply, in the Rev 4 manual it states:
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Your QMX is supplied with the bootloader installed, but not the firmware.?
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Note: you have to switch on QMX by pressing the left rotary encoder shaft button! In firmware update mode, the LCD is blank and the backlight is off.
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In the firmware update mode, the QMX pretends to be a USB Flash memory stick
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So I don't believe I should be seeing anything on the screen till I install the firmware and it does seem that the device should be recognized as USB storage. Unless I am wrong about either of these points...
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Hi Andrew,
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Not all USB cables are wired for data transfer. Some are for charging only. This could be one reason why you're not seeing the QMX as a USB drive.
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Regards,
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Mel. M0KMD
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Goodness, I'm embarrassed to say that I think this is the issue (I do not use USB C frequently in day to day life).

However, now when I look at the device on my windows machine I see that there is no EEPROM file. Is this a reason for concern or is it file to proceed and place the firmware file in the QMX "E: Drive"?

Many thanks,
Andrew
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Hi Andrew,
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Just download the firmware, unzip/extract the file and then copy and paste the extracted firmware in to the QMX USB folder.
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I think it should then reboot, but please check the instruction manual.
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Mel. M0KMD
 

It worked! Thanks for your suggestions Mel. I am being overly cautious as this is my first build but looks like everything is in order!
 

Andrew, that is correct, Hans just corrected me. My last build was a QMX+, so I thought that was also true of the QMX. Sorry for the confusion.
--
73, Dan - W2DLC
 

Are you sure your USB cable is data capable and not charge only.



13 Nis 2025 Paz 13:38 tarihinde Andrew (W3AWC) via <callsign.W3AWC=[email protected]> ?unu yazd?:

Hi All,
?
I just recently finished my QMX mid band kit and on powering up, my computer does not see any usb device. I have tried a computer running Windows 10 and another running Linux.
?
I have tried multiple combinations of plugging or having the device unplugged before power on.
?
I have been using a voltage and current limiter with a battery pictured below, limiting voltage to 7V then 9V (to see if that would make a difference) and limiting current to 250 mA.
?
In the pictures, you can see the device off then when I turn it on, the V out goes down slightly and there is a 170 mA current draw.
?
Thanks all for any suggestions,
Andrew
?
?
 

Happy to help, Andrew. :-)
Congratulations on you successful build!!! :-)
?
Mel. M0KMD.
 

Thanks Mel,
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It was my first big soldering project, I had only ever wound one toroid before this. I'm very satisfied (and relieved everything works) so far. Excited to try the radio but that might not be for a bit of time yet, given that I live in a city and need to travel a bit to find space to set up an antenna.

Below are a few pics from the process.
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This is a great community and I appreciate all who have answered my questions along my QMX building journey!

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73,
Andrew (W3AWC)
 

Andrew,
like our cat. You should know she is more important than all the weird stuff you are playing with.
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73 Ludwig
 

Ludwig,
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She is a treasure. Also a great supervisor as is apparent in the photo!
 

On Sun, Apr 13, 2025 at 05:36 PM, @Ludwig_DH8WN wrote:
You should know she is more important than all the weird stuff you are playing with.
Is what she is telling to you.

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