Ge

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Many thanks for the information I will get back to you with how I got on in a couple of days.?

Thanks again.

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Paul

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m0pnn

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My new assembled QMX+ showed up on my doorstep yesterday and I was very excited!? Everything checks out fine, but I find that I am disappointed in the reported power output levels: 160m 5.7w, 80m 4.8w, 60m 4.1w, 40m 3.9w, 30m 4.5w, 20m 3.3w, 17m 3.1w, 15m 4.5w, 12m 3.2w, 10m 3.8w, 6m 3.1w.? I am most disappointed with 3.3w on 20 meters since that is my goto qrp band.? I guess that I was expecting power output numbers on all bands to be closer to 5 watts.? Should I be disappointed?

works as expected... thanks Hans and team for the brilliant work....

vy 73 de Udo DF4BJ

I fitted all three to mine John. My U3 isn’t currently on the air due to a rearrangement of my antennas, though previously it has provided years of continuous service, it is just coming up to 11 years old. I remember that the GPS chip required some careful soldering, as this was before Hans developed a dedicated GPS module. 73 Nick G0OQK

Have you got a multimeter Rico?
A visual inspection of the solder joint is not sufficient in this instance if you are having problems. Set your multimeter to the resistance mode and check for low impedance across each coil. ?The measurement should be equal to that of the meter leads shorted together. My preference is to check on the coil side of the circuit board on the plated through holes where the coil wires pass through. This avoids the possibility of touching a bare wire end, that has not been properly soldered. ?Checking carefully means actually taking measurements in my opinion. Due to the large areas of ground plane acting as a heatsink, more care and attention than on other boards you may have soldered is required. 73 Nick G0OQK

Thanks, Stan,

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Using the refrigerator, I have confirmed that it is heat-dependent.? At 40 degrees, it took ~10 minutes to settle down. At 70 degrees, about 20 seconds.

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I wonder if there is a batch of QMX's with improperly soldered PCM1804's ? The thought of replacing the 1804 seems daunting, but I may look into a low-cost rework station.

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73,

Steve, N2IC

Tnx Todd,

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I’ve checked the soldering after I fitted the coils very carefully because I knew those are delicate.?

Interesting is the fact that the sound coming out of the little guy doesn’t change at all whether there is an antenna connected or not.?
But since I’m not good in electronics I’ve got no idea what to look at.?

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73 and merry Christmas

Rico, DG5BQ?

There are modifications for encoder mechanic you can do to get more slide filling.

Hello

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I am using a QMX and QMX+, but do not like the encoder to tuning the band up and down.

Every step is a grid.

Is there a replacement possible for the rotary encoder to tune the bands like on a K1/K2?

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73 de Harry, DK2GZ

Thank you Stan,

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This is so obvious I am not sure why I did not think about it!

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Sure, I loose autonomy but I will get my 5W till the end. I just hope that it isn't going to be noisy (was my thinking behind the linear regulator).

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73,

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Yannig - F4IUJ

Hello Alan,

thank you for the quick answer.?

I did the search for bad soldering already. Without finding anything.?
I kind of know how to solder but I don’t know how to find a problem on a board.?

So I think I’ve produced about 100,-€ of garbage, I’m afraid ?.?
73 and merry Christmas?

Rico, DG5BQ

It would just shut down. I would have to disconnect the power to get it to reset. ?In the case no problem. I was testing the RF power output on all bands. Just the normal cables connected between the rig and various RF output meters with a dummy load attached to it, morse key, battery and Drok voltage controller set at 11.9 v.

In the case it seems to work as the manual says. Power out was between 4 w on 40 meters and 5 w on other bands. 6 w on 160 and 80 meters.?

Hi John,

Glad you're nearly sorted. I don't use sma fittings on the relay board, I just solder coax direct, there are 3 large pads next to the sma placement. It also allows plenty of clearance should a gps board be fitted to the stack.

Andy

--

The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.

Hello experts ?

I just finished my build of the QMX 10-20m. During the first tests I found that the device is absolutely deaf on all bands. Measuring the board I figured that I have a short over all contacts of the antenna jack. I removed the jack. But still I do have continuity over all connection point.

Does anyone have an idea where to look next?

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Vy73 de Rico, DG5BQ

Just received my qmx 20-10 ... really the best Xmas gift ever ?

thanks Hans and team, wish a very nice Xmas and a happy new year....?

vy 73 de Udo DF4BJ?

I use a talent cell 12/3000 without any problems... in home shack I use the loading adapter of this powerbank.. works great since months

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vy 73 de Udo DF4BJ?

Hi Roland,

Is the resistance between R2/R3 and D1 still “zero” after you have reinstalled C3? If so, as suggested by Evan, please check if there is any solder bridge/whisker. Please check both sides of the PCB. A whisker can be very thin.

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There should not be a short there. If no bridge/whisker, then (1) either R2 and or R3, and (2) BS170 at Q6 need to fail as short circuit to create that status, I think. Is the resistance from R2/R3 to GND about 21.0 ohms?

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Hi Evan,

Thank you for stepping in. I really appreciate it. This gentleman’s amp worked fine one day (25W at 14V), but no output the next. His troubleshooting found incorrect voltages at L10, R13, the first step after checking of supply and 5V regulator voltages in the NA5Y’s video. We traced it to abnormal resistance at C3 and are stuck there now.

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73 de Aki, JO4MTH