Re: My #QMX died :-(
#qmx
There have been some upgrades to the power supply boards to make them more robust over time (higher wattage zener, higher voltage tantalum capacitor). So depending which Rev QMX pcb yours was built from, and when purchased, the best course of action may be to purchase a new power supply board set from QRP-Labs.?
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My first Rev 1 QMX had a similar fate.?
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73
de Roy - KI0ER
Littleton, Colorado USA
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I've found different impedance phones make a huge difference in the volume of the audio on all QCXs I've used.
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Make sure you're comparing like with like.
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73 Steve G4EDG?
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Re: My #QMX died :-(
#qmx
On Sun, Aug 11, 2024 at 03:02 PM, Peter Jacobi wrote:
Peter, use the assembly manual section "PCB diagrams". Ok it's a lttle bit hard to read D109. Afaik it's the diode at the edge of the PCB and close to D103. Zoom in in the PDF and you will find something like "D109".
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73 Ludwig
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The ARRL bookstore has a "Get on the air with HF Digital" book.? I have it and it's pretty complete.
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The published docs for each of the digital mode software are also pretty complete.
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Mark
KD0QYN
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Hi Wayne. Since it¡¯s an audio issue you should start by measuring the bias on all the op amps. Look for 2.5v on pins 1,2,3,5,6&7 of ICs 5,6,7 and 8. Also on pins 5,6&7 of IC9. Also look for just under 5v on pins 1,2&3 of IC9 and just under half the input voltage on pins 1,2,3,5,6&7 of IC10.? Also, were you able to get good nulls on IQ balance, phase lo, and phase hi. And what level did you reach on the BPF adjustment??
I have had the big one and the mini for a couple of years and luv-em'.
Thing is, the audio on the mini is way better than its big brother. I know I can just use the mini, but I like to use them all. So, if someone can point me in the right direction to start sorting it out, I would be much obliged.
Thanks,
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Wayne S.
KF7RCM
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Re: My #QMX died :-(
#qmx
Thanks for the info!
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PCB#2 (3.3V) is definitely kaputt, I did these tests:
PCB #2
1 ?Connect a 5.6V, 100mA max power supply to the GND and +12V pins.
? ? 1.1 ?VDD should be between 3.0 and 3.3V,?
My VDD: 0.5V
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2 ?Connect LIN_REG_EN to ground
? ? VDD should go low?
My VDD stays 0.5V
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3 ?REDUCE the input Volts to < 3.5V!!!??This is to protect the 3.6V Zener D109. ?Pull LIN_REG_EN low and PWM_3V3 high,?
My VDD goes up to 0.6V
My Lab Supply goes over 100mA
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My conclusion:
You are right, the Zener diode doesn't allow to go up to 3.6V it's nearly shorted.
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Let's hope, that there aren't more components affected.
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Question: where is D109?
It's hard to find on this little board.
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Thanks,
Peter DL4PJ
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Re: SOTA Batteries for QMX/QDX
A PD powerbank with both 12V and 9V voltages is a very useful option for those running FT8 and don't want to risk burning out their BS170s...
I believe Talentcell also offers a battery with both 12V and 9V output.
72 de Russ, va3rr
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Show quoted text
On Sun, Aug 11, 2024 at 07:41 AM, Daniel Conklin wrote: You can also get a 12v PD trigger board or cable for Power Distribution
capable systems. I have one trigger board that can provide either 9v or 12v
just by changing a switch. Make sure to plug the cable or trigger into the
battery before plugging into the radio.
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QMX+ straight key connection issue
All,
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??? I plugged my straight key into my QMX+ yesterday to discover it simply didn't work.? I plugged the same key into my K2 and it worked normally.? I then swapped the cable connecting the two and it started working normally on the QMX+.? The difference in the cables was that a "mono" cable (that presumably grounded the ring) worked on the QMX+ and a "stereo" cable (with the ring floating) wouldn't operate.? I verified this with other keys and cables.?
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???? Is this typical, or might I have done something wrong when I assembled the kit??
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???? If it is typical, is it intentional, or a bug?
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Bill
W2EB
East Syracuse, NY
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Might be relevant. Might not in your case.
Try the following:
Power off the QMX. Unplug the USB cable to the PC. Reboot the PC. Connect the USB cable from the QMX to a port on the PC. Then, power on the QMX. Use 'device manager' app on the PC to see if there are now audio devices showing AND a USB port for the QMX. Note the number assigned to the USB port.
This always works for me on my QMX radios. Have to do the same on my IC-7300.? This is on two different PCs since updating them to Windows 11.?
If you do see the audio devices and a USB com port assigned to the QMX then: You should be able to:
Use Putty to connect a terminal session to the QMX. -- use the 'Serial' mode in Putty and type in the correct COM port. And ... Configure WSJT-X with the assigned COM port and QMX audio devices to check basic overall connectivity.?
GREG KI4NVX?
On Sun, Aug 11, 2024 at 5:29 AM, John Laidler <rjohnlaidler@...> wrote: I have managed to complete the update but had to short the two pins as described in the operating manual. It didn't re-boot but powering down and then on again I was pleased to see it start as normal.
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However, the PC can't see the QMX as an audio device now, which it could before so I can't run digital modes.?
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If I'm feeling brave later I might try loading an earlier firmware, such as 024, and see if that makes any difference.
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John
M0WIV?
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Re: SOTA Batteries for QMX/QDX
You can also get a 12v PD trigger board or cable for Power Distribution capable systems. I have one trigger board that can provide either 9v or 12v just by changing a switch. Make sure to plug the cable or trigger into the battery before plugging into the radio.
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73, Dan - W2DLC
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Re: SOTA Batteries for QMX/QDX
Slightly off topic (because not 12 volt) but if anyone clicked this thread looking for ideas on how to power their 9 volt QMX, I use a small Anker USB-C power bank that supports USB-C PD. I combine this with a trigger module that requests 9 volts from the USB-C port. Works really well, and charging it is very convenient.
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Hi Andreas
"Low receive current (switching buck converters) 80mA; Transmit current 1.0 ¨C 1.1A (transmit dependent on power supply; example is approximately for 9V supply, 5W output)"
Ah OK. 80mA is for 12V supply with the backlight off... I should make that more clear in the next manual edit.?
73 Hans G0UPL
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Re: My #QMX died :-(
#qmx
Peter - I'm going to guess that one of your SMPS boards ist kaputt. I would examine both boards carefully for burnt components, at least as a starting point. The wiki is very useful in this regard. /g/QRPLabs/wiki/37128gl de Russ, va3rr
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Re: My #QMX died :-(
#qmx
Peter,
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it could be just that D108 Z-diode mentioned here:
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73, Andreas
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Hi Andreas, all ? Whether or not there is any problem on transmit is another question and I think requires some investigation. In semi QSK mode the clock is off during in between symbols. However since TX is still on (but un-keyed) it means one pair of the 4 PA transistors is ON. That shouldn't matter because the PA modulation voltage should be zero. But PA modulation voltage is high during receive. If the PA modulation voltage is also put high between keying symbols in TX in semi QSK mode then that would be a problem as one pair of transistors would conduct DC directly to ground, and it would explain high heat in CW operation (TX) but not so much in Digi. I don't think this is the case, but due to this email thread, I think I do need to check it, to be certain.?
I did just test this, I couldn't wait for Monday morning ;-)? ?The PA modulation is correct. In QSK mode (Semi-QSK = OFF), the PA voltage returns to?+V during the gaps between keying. In Semi-QSK mode it remains low. So the fact that one pair of transistors is ON during the gaps between keying does not cause high current flow (or increased compared to before). Therefore I concluded there isn't a firmware fault.?
However - this change in 1_00_024
"8. Switch off CLK2 carrier during key-up between Semi-QSK"
*Might* have un-masked?a hardware fault in your QMX which you were otherwise unaware of. If the Q507 transistor is dead or any other fault in the PA modulator (which controls Q507) causes the PA modulator to not be working properly, and if it is always high (regardless of the microcontroller's attempts to control it) then firmware 1_00_024 would in fact uncover this fault, by causing high current draw in the gaps between CW symbols when in Semi-QSK mode.? You could check this by running the Diagnostics screen. When NOT keying, in the transmitter section of the screen in the bottom right, voltage should be quite low (mine shows 0.4V now, see attached). If there is a fault in the PA modulator, that would be a higher voltage nearer to the supply voltage and it would be coloured RED. A screen with an green font,?like the attached example, is healthy.?
73 Hans G0UPL
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Thank you for the clarification, Hans!
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I have no notes from the past so my reference was only the assembly manual where it says on page 3:
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"Low receive current (switching buck converters) 80mA; Transmit current 1.0 ¨C 1.1A (transmit dependent on power supply; example is approximately for 9V supply, 5W output)"
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73, Andreas
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Hi,
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I wanted to measure the power consumption, so I connected the QMX to my lab supply with an ampere meter.
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The connection was not reilable.
First the QMX started normally. When I moved it, there must have been a very short disconnection to power.
It showed black boxes? on the screen and made a hissing sound.
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When I press ON now, it draws 0.7 A on 12 V. The linear power regulator 78M33C heats up quickly. No light, no display.
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Any chance, that I can repair the QMX?
Which components can be broken?
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Thanks
Vy 73 de Peter DL4PJ
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Ok, Hans, but would you consider 122mA @ 9V on RX as normal? IIRC it was more around 80mA in the past...
I just now switched on a QMX here. It's running formware 1_00_018 (I didn't use it for a while). But anyway there haven't been any changes in RX power consumption from firmware changes. On my cheap probably-inaccurate bench PSU's voltage and current meter I get:
88mA @ 12V supply 115mA @ 9V supply
It's perfectly normal for the supply current to increase as the supply voltage decreases because of the internal switching regulators.?
No QMX has ever consumed 80mA at 9V. You could be around that with backlight off and at 12V or a little over. But not at 9V. So I think:
a) your recollection is probably not quite accurate and b) your measured 122mA RX current at 9V is perfectly normal?
Whether or not there is any problem on transmit is another question and I think requires some investigation. In semi QSK mode the clock is off during in between symbols. However since TX is still on (but un-keyed) it means one pair of the 4 PA transistors is ON. That shouldn't matter because the PA modulation voltage should be zero. But PA modulation voltage is high during receive. If the PA modulation voltage is also put high between keying symbols in TX in semi QSK mode then that would be a problem as one pair of transistors would conduct DC directly to ground, and it would explain high heat in CW operation (TX) but not so much in Digi. I don't think this is the case, but due to this email thread, I think I do need to check it, to be certain.?
73 Hans G0UPL
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Ok, Hans, but would you consider 122mA @ 9V on RX as normal? IIRC it was more around 80mA in the past...
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Hi all
I don't know of anything that could cause higher current consumption (and heating) in 1_00_026. The higher CPU load in CPU was also the case in earlier versions with the single choice of CW filter. Note also that the CPU load is an indicator of active processes. The CPU doesn't sleep when it is not needed for processes. It just loops around checking stuff more often than is necessary. So the CPU is always 100% busy doing something, there isn't any dynamic current consumption that relates to the indicated CPU load in the CPU monitoring screen.?
73 Hans G0UPL
The only other difference that I noticed is a slightly higher CPU load of 39..40% on RX.
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Maybe a result of the new CW filters?
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It used to be around 33%.
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Steve G4EDG
Ronald Taylor
va3rr
Daniel Conklin
Willem VA2WLM