I don't think it is just me that uses QMX as an HT, so there can be different versions of QHX. This is about my version of QHX, integrated with the 2s 14500 batteies and the micro-size single lever paddle.

I didn't think I would need a log tray like KH1's, because I've been using my phone's note app for writing the logs. But when my one hand is already occupied by the HT and the other needs to stand by for cw keying, using the smartphone for logging is not convenient anymore. So here's a quick dirty prototype made with a thin plastic sheet. Someone would make a much nicer one with a 3D printer, I guess.



When it is closed (folded) it works as the screen protector (partially protecting the micro cw paddle as well) and also the volume button stopper to prevent the radio from accidently turning on. The metal hinge is scavenged from an old eyeglasses case, and maybe I can attach a steel pen with some magnet on it.



Opening it up, I can use it as the logging pad, though the pad is small and not so comfortable for writing anything well. The clear plastic sheet is from some product packaging, and it is not very firm. Some harder material would be more stable for writing on. For the logging sheets, I would be using Post-it cut for the size. Maybe a few sheets would be enough for about 10 QSO's or an hour of handheld walkabout operation.

73,
Yoon KM6KJI

开云体育

You might also use the terminal mode to run the diagnostic to be sure that the encoder and all are working... That's all described in the assembly manual.

Also, when you power on, is it showing you version 14?

Paul -- AI7JR

Juan,

Maybe the issue is the earphone jack?? Can you try connecting a speaker to the board connections of the jack?? The other possibility is the audio amplifier has failed.? Do you have a way to connect an earphone to the output of either C420 or C421?

73
Evan
AC9TU

-- 
Paul -- AI7JR

Hmmm... Good news and bad news.

1. I took voltage readings from Q507 (AOD403) with my 12v QMX powered on as follows:
Source: 11.98v
Gate: 11.88v
Drain: 6.6v

With the device powered off, I measured a 49.8ohm resistance between the source and the gate.?

2. Then I proceeded to remove the Gate (left-most) pin of Q507 from its pad, so that it was isolated in mid-air. Powered on, I measured:
Source: 11.97v
Gate: 11.97v
Drain: 6.6v

Powered off, I still measured 50ohms between Source and Gate and, incidentally, 5.58k across R507 (which had been reading 50ohms).

The voltage into the transmitter was still high at 5.8v in receive and in transmit. I had kind of expected that to fall to 0 with Q507 half-way removed.?

3. Therefore I determined to lift the other leg of Q507. Which I did, resulting in a transmitter voltage of .6-.9v. Beautiful! It seems to me there's a pretty significant chance that Q507 really is the culprit, having been shorted to the transformer (T501) when I initially powered on.

Bad news: In try to lift that second leg of Q507, I plugged in my (smart!) soldering iron but neglected to ensure I had turned it on. I lifted the pad on a perfectly cold connection. If only the operator was as smart as the soldering iron (a nifty Pinecil 2). Argh!





So, my new question: is there any point in ordering a replacement AOD403? Or is my QMX now a receive-only device and expensive code oscillator?

Presently two of the three pads are still good. I wonder if I could make it work by tacking a 5.6k resistor and a 0.1u capacitor on top of the device. I would need to find myself a convenient ground and, more challenging yet, a +12V source.

Juan,

Maybe the issue is the earphone jack?? Can you try connecting a speaker to the board connections of the jack?? The other possibility is the audio amplifier has failed.? Do you have a way to connect an earphone to the output of either C420 or C421?

73
Evan
AC9TU

Thanks for your responses Ron and Evan. I did what Ron told me to do and I also did the factory reset but the volume control still doesn't work, that is, I can't raise or lower the volume from the volume knob.
73, Juan LU9CYV

Juan,

Did you do the factory reset?

73
Evan
AC9TU

I was able to update the firmware to the latest version, but the volume control still does not work
73, Juan LU9CYV

Bela,

The Y0 to Y3 is the base two numbers of the Band_0 and Band_1 input.

Band_0? Band_1? BPF Selected
0? ? ? ? ? ? ?0? ? ? ? ? ? 0 - Y0 connected to W
1? ? ? ? ? ? ?0? ? ? ? ? ? 1 - Y1 connected to W
0? ? ? ? ? ? ?1? ? ? ? ? ? 2 - Y2 connected to W
1? ? ? ? ? ? ?1? ? ? ? ? ? 3 - Y3 connected to W

Note that BPF 0 is the highest frequency band, and BPF 3 is the lowest frequency band for the build.? This is selected using the Band Configuration screen.

73
Evan
AC9TU

Yes, The QMX can not get power from the USB cable.? It needs a separate power supply.? This is best done for the first time with a current and voltage controlled supply, starting at 6.5 to 7 volts, limited 250ma.? A power cycle is needed whenever the USB cable is disconnected from the PC.? The QMX does not always let the PC know how to connect.

73
Evan
AC9TU

A stupid question....
Does the QMX have to be connected to power for the computer to recognize it?
73, Juan LU9CYV

Thank you very much Evan for you response.
73, Juan LU9CYV

Hi Team, I got a QMX that stopped receiving on 30m and 20m bands. It looks not a LPF issue. Could someone elaborate how QMX selects the RX bands with the Band_0 and Band_1 signals? See marked below on the schematics:

What are the combinations for the different bands?

?
73 de Béla

Juan,

You need a terminal emulator program that works with Windows.? I use PuTTy:


Download and install the program following instructions on the site.? Once the program is loaded, you will need to verify which Com Port is connected to the QMX.? I do this using the Windows Device Manager app with a right-click on the Windows Icon.

Open the app and then the Ports folder (this is from my Windows11 Laptop):



Here is the same screen using my Windows10 PC that I connect to my QMX:


The above is before I connect the QMX.? With the QMX connected, I get this:



Note that for me, the new COM port is COM3.


Now open Putty.

Now start Putty.? You should get a screen like this:


Select the Serial button and enter the com port from the Device Manager (COM3 for me).??


Click on the Open button.? A blank window opens:



Press the enter key, and the main menu should open:



The rest is in the operations manual.

73
Evan
AC9TU

Hi Gerald,

Recently got my pre-built QMX. Upgraded to ver 14...I'm having the exact same key click issue. Your recording is exactly what I'm hearing. I hope Hans is able to figure this out...it's horrible to listen to on headphones,

73,
D. Altman
KO4YLZ

Hello.

Juan,

I should mention that what you described was a bug that has been repaired in the current firmware version 1_00_014.

Hello, again Juan,

I suggest starting with the operations manual available on the QRP-Labs QMX webpage:


You should upgrade the firmware as instructed in the operations manual.? The upgrade process is described on page 56 of the current operating manual.


Verify operation, and if there is an issue, then try a Factory Reset as described in the Operations manual.

Since you purchased a QRP-Labs built QMx, I would contact QRP-Labs support and request information on how to send them the unit to be repaired if the above can not resolve the issue.

73
Evan
AC9TU