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Still no output on QMX

 

checked, Q508 is good. Thank you for the additional info.?
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James
 

Okay, after replacing Q507, rewinding T501 back to the WTST 9V (using Hans suggested 3.3mm magnet wire) rewinding L502 with 3.3 Magnet wire, and L405A ( it looked sloppy) I get 3.4 watts output on 60 meters. Unfortunately, my display stopped working (just a line of squares across the screen) and sometimes I can't shut it off without unplugging it. Sometimes the only way to turn it on is by shorting Q104 on the power supply board. I think this rig picked up a poltergeist in it's travels. I can't move forward with the output until I find out what happened to the display, which did work perfectly.?
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Am I mistaken, I think I was told that the SMPS status is only supposed to turn on when you press the "T"? while running the diagnostics and should stay off when pressing the "P" key.?
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UpDate---Display is now working.?
 

did you have a good dummy load attached when you pressed T to turn on transmit?? The SWR of 2.8 is much higher than it should be.? With a 50ohm dummy load it should be 1.1 or so.

On Wed, Sep 25, 2024 at 9:11?PM James via <jmrobertsjmr=[email protected]> wrote:
UpDate---Display is now working.?
 

Hi Ludwig, I have some output numbers for you.
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60M-<.5W
40M-<.5W
30M-<.2W
20M-9.9W
17M-8.4W
15M-5.5W
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Do you have an idea why there's very little output om 60M-30M and too much on 20M & 17M?
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Also the swr on the diagnostic screen is higher than what my SWR/Power meter says. Like I mentioned before, my dummy load measures 49.7 OHMS.?
After the QMX gets warm, I can no longer power it down unless I unplug it. Do I also have a power supply problem?
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Sorry for being such a pain.
James
KA9TII
 

The high-band powers look like you wound the transformer for 9V but are running with 12V.

On Wed, Sep 25, 2024 at 9:59?PM James via <jmrobertsjmr=[email protected]> wrote:
Hi Ludwig, I have some output numbers for you.
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60M-<.5W
40M-<.5W
30M-<.2W
20M-9.9W
17M-8.4W
15M-5.5W
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Do you have an idea why there's very little output om 60M-30M and too much on 20M & 17M?
?
Also the swr on the diagnostic screen is higher than what my SWR/Power meter says. Like I mentioned before, my dummy load measures 49.7 OHMS.?
After the QMX gets warm, I can no longer power it down unless I unplug it. Do I also have a power supply problem?
?
Sorry for being such a pain.
James
KA9TII
 

Looks that way but if you look at the screenshots, you can see I'm using a 9V supply.
 

Yes, I just rechecked my dummy load to be sur and, it measures 50.1 Ohms.
 

On Thu, Sep 26, 2024 at 05:59 AM, James wrote:
Do you have an idea why there's very little output om 60M-30M and too much on 20M & 17M?
?
Also the swr on the diagnostic screen is higher than what my SWR/Power meter says. Like I mentioned before, my dummy load measures 49.7 OHMS.?
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James, there are more than one possible reason for the shown values (e.g. T507, LPF section, cables, dummy load). It would be helpful to have some additional values. Could you show for each band:
for RX - supply voltage and current
for TX into dummy - supply voltage and current, from Diagnostics screen PA voltage, output and SWR, from SWR/Power meter output and SWR
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Could you show some pictures,
  1. for T507 one from each end and one from the bottom side of the PCB,
  2. for T501 one from each end,
  3. the whole setup with QMX SWR/Power meter and dummy and
  4. the dummy?
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After the QMX gets warm, I can no longer power it down unless I unplug it. Do I also have a power supply problem?
Maybe.
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Sometimes the only way to turn it on is by shorting Q104 on the power supply board.
This points in the same direction.
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UpDate---Display is now working.?
How did you bring it to work?
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Am I mistaken, I think I was told that the SMPS status is only supposed to turn on when you press the "T" ?while running the diagnostics and should stay off when pressing the "P" key.?
If you mean the BIAS SMPS it should be ON for "P" and "T".
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73 Ludwig
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?
 

 

? QMX Diagnostic Results Idle
? ? ? ? ? ? ? ? ?
? Bench Supply 9V ? Diagnostic Screen
? ? ? ? ? ? ? ? ?
Band Voltage Current? SWR Voltage PA 3V3 PA 5V SWR Bias SMPS
? ? ? ? ? ? ? ? ?
60M 9V 0.112 1:1 .3V 3.34 5 ? Off
40M 9V 0.112 1:1 .3V 3.34 5 ? Off
30M 9V 0.112 1:1 .3V 3.34 5 ? Off
20M 9V 0.112 1:1 .3V 3.34 5 ? Off
17M 9V 0.112 1:1 .3V 3.34 5 ? Off
15M 9V 0.112 1:1 .3V 3.34 5 ? Off
? ? ? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ?
? QMX Diagnostic Results "P"
? ? ? ? ? ? ? ? ?
? Bench Supply 9V ? Diagnostic Screen
? ? ? ? ? ? ? ? ?
Band Voltage Current? SWR Voltage Bias SMPS Power SWR Bias SMPS
? ? ? ? ? ? ? ? ?
60M 9V 0.127 1:1 .3V 30.3 ? ? On
40M 9V 0.129 1:1 .3V 30.4 ? ? On
30M 9V 0.13 1:1 .3V 30.4 ? ? On
20M 9V 0.132 1:1 .3V 30.4 ? ? On
17M 9V 0.133 1:1 .3V 30.4 ? ? On
15M 9V 0.134 1:1 .3V 30.4 ? ? On
? ? ? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ?
? QMX Diagnostic Results "T"
? ? ? ? ? ? ? ? ?
? Bench Supply 9V ? Diagnostic Screen
? ? ? ? ? ? ? ? ?
Band Voltage Current? SWR Voltage Bias SMPS Power SWR Bias SMPS
? ? ? ? ? ? ? ? ?
60M 9V 0.92 1:1 7.2 30.5 <.5 W 2.53 On
40M 9V 0.803 1:1 7.3 30.5 <.5 W 2.7 On
30M 9V 0.942 1:1 7.2 30.5 <.5 W 2.67 On
20M 9V 0.84 1:1 7.4 30.5 9.6 W 2.66 On
17M 9V 0.872 1:1 7.4 30.5 8.6 W 2.62 On
15M 9V 1.001 1:1 7.1 30.5 5.2 W 2.54 On
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I brought the Display back by shorting out the "Force Firmware Update" pins
 

On the face of it the RF power readings are unrealistic when compared with the DC readings; on 20M you show 9.6W out with a DC input of 7.56W, an efficiency of 126%.
73, Don N2VGU
 

<On the face of it the RF power readings are unrealistic>
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What are you saying Don? Let me post a screen shot on 20M. I only provided one on 60M because I couldn't change bands on the unit while plugged into the computer. I only just realized I could change bands inside the puddy app.
 

On Fri, Sep 27, 2024 at 01:26 AM, Donald S Brant Jr wrote:
on 20M you show 9.6W out with a DC input of 7.56W, an efficiency of 126%.
James, like Don wrote its impossible (or the Nobel Prize ;-)).
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Thanks for the lot of information.
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To the pictures and tables:
  1. Looking at picture 6 and 7 I see something light green at a solder of T507. What is it?
  2. At picture 7 right bottom one pin of IC402 looks like disconnected from the pad. Its important for RX.
  3. I'm not sure about the solder of one 10 turn winding of T507 (connection near D513). Picture 8 looks like no solder in the hole but maybe on the other side of the PCB.
  4. Tabel 3 contains two rows SWR, the first 1 all the time and the second around 2.6. From where comes each value?
  5. Are there values delivered by your external SWR/Power meter?
  6. Could you check SWR for 15 m band from Diagnostics screen for these setups:
    QMX - cable 1 - dummy
    QMX - cable 2 - dummy
    QMX - cable 1 - ext. Meter - cable 2 - dummy:
    Are there significant differences?
  7. Did you check the rf impedance of your dummy load? I'm not sure about the rf characteristics of the used resistors.
73 Ludwig
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On Fri, Sep 27, 2024 at 08:06 AM, @Ludwig_DH8WN wrote:
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? ? ? 1. Looking at picture 6 and 7 I see something light green at a solder of T507. What is it?
? ? ? ? ? PCB Mask. I rewound T507 3 times and I scratched the board.
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? ? ? ?2. At picture 7 right bottom one pin of IC402 looks like disconnected from the pad. Its important for RX.
? ? ? ? ? ? ?I checked each leg of IC402 for continuity from pin to destination. All good.
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? ? ? ?3. I'm not sure about the solder of one 10 turn winding of T507 (connection near D513)
? ? ? ? ? ?The connection is good, on top side.
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? ? ? ?4. Tabel 3 contains two rows SWR, the first 1 all the time and the second around 2.6. From where comes each value?
? ? ? ? ? ? The first is from my bench SWR/Power meter, the second is off the puTTy diagnostic screen.
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? ? ? ?5. Could you check SWR for 15 m band from Diagnostics screen for these setups:
? ? ? ? ? ?I'm sorry, I don't understand what you are asking for.
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? ? ? ? 6. Did you check the rf impedance of your dummy load?
? ? ? ? ? ? I only measured the resistance. I'm not sure how to check the RF Impedance. I can retest using a commercial dummy load if necessary.
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I did not send you the power output readings from my bench SWR/Power meter. I will run these test again with the commercial dummy load.
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Thank you Ludwig and all others for their input,?
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James?
 

On Fri, Sep 27, 2024 at 08:12 PM, James wrote:
?5. Could you check SWR for 15 m band from Diagnostics screen for these setups:
? ? ? ? ? ?I'm sorry, I don't understand what you are asking for.
Its for testing the cables/ adaptors/ the meter for a possible fault.
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QMX - cable 1 - dummy
QMX - cable 2 - dummy
QMX - cable 1 - ext. Meter - cable 2 - dummy
First you would use only cable 1, second cable 2 and then cable 1, 2 and the meter for connecting the dummy. If all is ok (and the dummy good for rf) the SWR measured by the QMX should be nearly the same. If not this would mean a problem with some of this stuff.
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I only measured the resistance. I'm not sure how to check the RF Impedance.
E. g. with a VNA or with a reliable SWR meter. Regarding the SWR = 1 you've found it should be ok. Using a commercial dummy load would be a good proof.
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Could you check the band configuration which LPF is allocated to which band? You will find this via the terminal session.
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Your high output for 20 m ... 15 m looks like the real value is multiplied by 2 or so. The low output values for 60 m ... 30 m could be a result from an overflow. So its good to know which output is measured by the external meter.
All the supply currents in table 3 are good for an output of a few watt.
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73 Ludwig
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