Re: QMX/QMX+: Steps to safe antenna tuning and powering the unit
Thanks all for your help and information.
FYI:? I received the above listed reducer from Amaz## and it allows you to lock the max voltage.? I experimented with my variable power supply and for example, when I set the reducer to 12v, adjusting the power supply above 12v leaves thee output power at 12v.? Any power supply setting below 12v reflect the same output power.? The LCD lighted display can show both in/out voltage and amps.? Now I need to create a plastic storage container to house the Bioenna battery.
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John,
RF Sweeps and AF sweeps are pure garbage.?
No scope here.?
Using Raspberry Pi for testing.?
Regarding using Audacity just run audio output from the QMX into Audacity?
I thinking I'll just go ahead and order the IC. Looks very likely it's bad.
RF Sweep
AF Sweep
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Show quoted text
Roger that.
That check can be done but it is a bit complicated and only works if you can? actually hear signals.
First off, bad IF sweeps are a big clue. If one ADC channel has failed then IF sweeps will show no suppression of the unwanted sideband
If the sweeps are just noisy garbage, perhaps both ADC channels have failed.
Going deeper:
Tune in a constant carrier to produce an audio beat note near 700 Hz.
Using the oscilloscope, verify that clean sine waves exist at pin 1 of IC405 and IC406. The signals should be near 12KHz in frequency and 90 degrees out of phase. If so,? the entire RX chain ahead of the ADC is good.
Via the terminal program,? put the QMX in IQ mode and observe the I and Q channels via the PC Audacity audio app. You should see two channels of approximately equal signal amplitude. Otherwise, something is wrong.
JZ
Ok, no harm in trying.?
Before I order the part for the PS Board, is there a way to check if the PCM1804 is good. Save on shipping if I order both at the same time.
It can be done, Cliff. I successfully did one recently. Of course Jeff Moore is there to help!
JZ Ouch! That one looks like it's beyond me to change out. If it proves bad guess I'll give it a go, but ......
Cliff, yeah, I am also concerned that this is not the last layer of the onion that needs to be peeled down.
Overvoltage on the 5V supply rail tends to take out the PCM1804 ADC chip. Its analog front end runs on 5V, the digital portion on 3,3V. It is the weak link of all the devices that run on the 5V rail. That may be the source of the unstable readings you see with the "good" SMPS module.
Keeping fingers crossed...JZ Ok, thanks. I like Mouser an they ship for $5 and I get it next day as they are close to me. I'll look at Digikey.
If this fixes the PS board then I'm puzzled about what else is not right. Fluctuating 5V rail and won't shut down. Hopefully that is an easier fix. Q108 is pretty tiny. Fun to change it.
Ouch! Cliff, I think you found the culprit.? Digikey has the AO3415.
JZ Yes, Q108 is bad. Measurements 20 - 50 ohms.
Next question, looking at Mouser AO3415A doesn't come up. I get a PJ3415 to come up. Is there a better part number?
Agreed, Cliff. That looks OK. Try the same test on Q108. Let's see what we have there.
JZ John,
Drain-Source - Starts out at 10K then charges up to 22K+ (same regardless of +/- orientation, Gate-Drain 110K, Gate - Source 99K. Seems good to me. ?
Cliff , Remove the module from the main board. Locate Q106. Using an ohmmeter, check the resistance at Q106: gate-source, gate-drain, drain-source. All readings should be above 10K ohms. Any reading much less than that suggests a problem.
John,
How would I do that? Checking in circuit and comparing with the good and bad boards they seem very similar in all combinations of resistance measurements.
Duty cycle =0! That means the MCU is doing all it can to throttle back the 5V SMPS and is finding it has no control at all.
Possibly one or more damaged transistors on the 5V SMPS module.
I would check Q106 for shorts.
JZ Ludwig,
The QMX will not boot at 7V. 9V will let it boot so the screen shot if with 9V.
As it sits there the 5V varies up and dow a little. If I go to 10V in it varies up 5.8 or so. On May 29, 2024, at 15:59, DH8WN via ??< DH8WN@...> wrote:
Cliff,
it looks like a problem in the control loop.
How and where did you measure VCC?
If really 6 V and more D108 on board #1 must be broken or disconnected. But this isn't the reason for the high VCC. It's only a lack of protection.
Please show a screen shot of Terminal - Hardware tests - Diagnostics. But use only around 7 V input to protect the QMX. And what is VCC in this situation.
73, Ludwig
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Excellent Ludwig, I was looking for this diagram but couldn¡¯t find it. Thank you.
Tony
On Thu, May 30, 2024 at 10:37 PM, Tony Scaminaci wrote:
I¡¯d venture a guess that Hans has limited the low-end SMPS duty cycle to >= 20 %
Cliff and Tony,
could be but with the broken SMPS it was 0 %. It's mysterious without knowing the software.
I see the ADC_5V and PWM_5V signals at jumpers JP_101 and JP_102 on PCB #1 board itself. Other than that, I don¡¯t see any good places to probe them.
Some times ago I found a post with a related document. This document seems to be deleted now. But I stored it local and here it is (see attachment). Maybe it will help.
Automatic switch-on looks like a problem at the left side of schematics of PCB#1. Is there a bad GND connection PCB#1 to mainboard?
Did you check the SMPS offline (see here)?
73, Ludwig
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Sorry, I made two posts and with this three in a row.
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On Thu, May 30, 2024 at 06:14 PM, Cliff wrote:
Replaced with good PS#1 and see screen shot below. DVM reads 5.3V where as Diag screen shows fluxuating 4.8 - 5.4V.
It would be nice to check by an oscilloscope (osci GND one time to SMPS GND and one time to QMX GND; but don't bypass GND via power supply). Maybe there are ripple at VCC. The GND connection PCB#1 to mainboard is suspicious to me. 73, Ludwig
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On Thu, May 30, 2024 at 10:37 PM, Tony Scaminaci wrote:
I¡¯d venture a guess that Hans has limited the low-end SMPS duty cycle to >= 20 %
Cliff and Tony, could be but with the broken SMPS it was 0 %. It's mysterious without knowing the software.
I see the ADC_5V and PWM_5V signals at jumpers JP_101 and JP_102 on PCB #1 board itself. Other than that, I don¡¯t see any good places to probe them.
Some times ago I found a post with a related document. This document seems to be deleted now. But I stored it local and here it is (see attachment). Maybe it will help. Automatic switch-on looks like a problem at the left side of schematics of PCB#1. Is there a bad GND connection PCB#1 to mainboard? Did you check the SMPS offline ( see here)? 73, Ludwig
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Re: QMX MB - Wonky SWR Sweep
GL and others,
I'm embarrassed to report that heat took care of it--or mostly. 60, 40, 30 & 20 all have SWR sweeps below 1.3:1. Thank you!
Hitting 'T' in putty yields about 1.25 watts for each freq at 12V.?
17m and 15m are still a little weird--lots of unevenness on either side of the targeted (vert line) freq, which is coming in at about 2.5:1. No output hitting 'T', but a few hundred mA are triggered.?
Not sure why the two high freqs show high SWR--I'm assuming it's unlikely to be T507 since the other bands are good. Is that right? If you have any thoughts on this I'd appreciate it.
The low power output on the lower freqs I can probably address by adjusting the winds on the appropriate toroids, right?
But the 0 output on the high freqs--is that possibly due to the high SWR? Does the Putty application trigger output protection like the radio working autonomously does? All suggestions are welcome. Many thanks.
Mitch NK3H
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Re: Reasonably priced CW paddles
John,
I built 4 of these K6ARK paddles for about $40.?
I'm lucky enough that my public library has a Prusa 3D printer and they charge filament by the gram.? Printed parts enough for 4 paddle sets was just under $10.? The remaining materials from Amazon.com were about $35 and I have enough spare hardware for 6 more units.
Landed price right now for four units is $10 each, so no big deal if I break one in the field.? If I finish the build out ($15 for six more sets of paddle plastics) puts the cost at about $5.50 each.?
They work pretty dang well and I haven't broken one yet.? I would recommend the closed-side model with the low profile paddles, fits nice in an Altoids tin with the 3.5mm patch cable.
I also have one of the stainless steel eBay mini-paddles.? It is quite robust with very strong magnets.
Nate,
AC1AS
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Jay, are you using sidetone absolute or relative? Relative worked much better for me in additional to sample blocks = 2.
-Steve K1RF
------ Original Message ------
Date 5/30/2024 4:36:29 PM
Subject Re: [QRPLabs] CW Issues
Steve & Group: I tried the suggested AGC settings (below) and keying has clicks. Tried again with SAMPLE BLOCKS 2 and no changes. I'm back on AGC OFF. Thanks & 73 Jay W6CJ
Parameter | Value |
|----------------------|-------|
| AGC | ON |
| Threshold S | 7 |
| Slope dB per dB | 60 |
| Noise filter | 5 |
| Hang time | 30 |
| Smooth samples | 50 |
| Recovery dB/s | 50 |
| Sample blocks | 4 |
| S9 sounds like S | 9 |
| AGC display | ON |
| AGC dB per bar | 3 |
Thanks for all the suggestions... The key clicks are virtually gone after using the AGC settings from /g/QRPLabs/topic/104712439 . Thanks for the info on 600 Hz being the smallest off
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DuckDuckGo did not detect any?trackers.
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Unable to verify sender identity
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Thanks for all the suggestions... The key clicks are virtually gone after using the AGC settings from /g/QRPLabs/topic/104712439 . Thanks for the info on 600 Hz being the smallest offset. Matched with a 600 Hz sidetone, that works for me. Would still be nice to have semi-QSK, with a selectable hold time. 73, Steve, N2IC
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Hans- TNX.?? v019 resolved the problem of the frequency display freezing when tuning the encoder. 73
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Re: QMX+ USB-C Connector solder joints
Dj,
Hey neighbor!? Are you going to bring that QMX+ to Lobstercon2024?
-Nate AC1AS
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Ivan, TNX - RX audio sounds much better! 73
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Jay, here are my settings on a low band QMX Rev1 (See attachments). Your sample blocks need to be set to 2.? That will make all the difference.
- Steve K1RF
------ Original Message ------
Date 5/30/2024 4:36:29 PM
Subject Re: [QRPLabs] CW Issues
Steve & Group: I tried the suggested AGC settings (below) and keying has clicks. Tried again with SAMPLE BLOCKS 2 and no changes. I'm back on AGC OFF. Thanks & 73 Jay W6CJ
Parameter | Value |
|----------------------|-------|
| AGC | ON |
| Threshold S | 7 |
| Slope dB per dB | 60 |
| Noise filter | 5 |
| Hang time | 30 |
| Smooth samples | 50 |
| Recovery dB/s | 50 |
| Sample blocks | 4 |
| S9 sounds like S | 9 |
| AGC display | ON |
| AGC dB per bar | 3 |
Thanks for all the suggestions... The key clicks are virtually gone after using the AGC settings from /g/QRPLabs/topic/104712439 . Thanks for the info on 600 Hz being the smallest off
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DuckDuckGo did not detect any?trackers.
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Unable to verify sender identity
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Thanks for all the suggestions... The key clicks are virtually gone after using the AGC settings from /g/QRPLabs/topic/104712439 . Thanks for the info on 600 Hz being the smallest offset. Matched with a 600 Hz sidetone, that works for me. Would still be nice to have semi-QSK, with a selectable hold time. 73, Steve, N2IC
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Jay, try to set Sample blocks=2, Sidetone volume to 70 and Sidetone from absolute to relative.?
73, Ivan, 9A7AM
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The turns direction with regard to each of the binocular core is important.? When wound in the correct directions, it works.? If one is improperly polarized with regard to the other one, it doesn't work. If you have a working VSWR bridge and (thought experiment) reversed the wind directions of both coils, it would still work.
-Steve K1RF
------ Original Message ------
Date 5/30/2024 2:34:15 PM
Subject [QRPLabs] T507
Well at the risk of looking foolish I need to ask about this bino. I've wound a few of these in other projects but never been certain I was doing it right.?
I've wound T507 opposite handed. That is started both secondaries from the bottom and then outward. Is this correct or should I have started from opposite ends? OR does it not matter?
Not sure why I can't work this out and searching just seems to lead to controversy.
Thanks
--
Phill EA5JHA
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Cliff,
I see the ADC_5V and PWM_5V signals at jumpers JP_101 and JP_102 on PCB #1 board itself. Other than that, I don¡¯t see any good places to probe them.
Beyond this, I¡¯d venture a guess that Hans has limited the low-end SMPS duty cycle to >= 20 % from your screen shot which would explain why it¡¯s showing 5.44V. Some leakage problem still remains that¡¯s putting more voltage on the 5V rail that the firmware can¡¯t correct for. This is a good thing because Hans knows what the valid duty cycle range is for a good system so you have a problem elsewhere as JZ indicated.
Tony
Tony,
Thanks. I already have them, but I don't see any info on what info is available on the row of pads, upper left top of the main board. Is the info there in the schematic and I just can't see it?
On May 30, 2024, at 15:00, Tony Scaminaci via < tonyscam@...> wrote:
Cliff,
Here¡¯s a link to the schematics: Tony? Where would I find a description of the pinouts on the QMX board, i.e. the row of contacts on the?
upper right hand edge of the board? I want to measure the ADC 5V, PMW 5V etc. Trying to measure on the components looks tricky and easy to short something.
Ludwig and others,
Ok, still no duty cycle at 10V with bad PS#1. DVM shows 5.3V at 9V in and 6V and 10V in.
Replaced with good PS#1 and see screen shot below. DVM reads 5.3V where as Diag screen shows fluxuating 4.8 - 5.4V. Now there is duty cycle of 20%
Noticed something that may be a clue, with the good board I can't shut the QMX down in the usual way. It tries to shutdown then reboots back up. I need to cut power to shut down. Hmmmm....
What think ye? <QMX-12V-Good PS board.png> On May 29, 2024, at 18:30, Tony Scaminaci via ??< tonyscam@...> wrote:
Good point Ludwig. The PWM_5V signal is directly connected to the microprocessor. If Q106 is shorted on the original switcher board, the uP¡¯s pin could be damaged. This could explain why the swapped switcher board is behaving somewhat erratically. On Wed, May 29, 2024 at 11:45 PM, Cliff wrote:
Another bit of info, I replaced the PS#1 board with one from another QMX. It worked ok, but the voltage varied quite a bit just sitting there, like .3 or .4 volts. Cliff, I hope the overvoltage didn't damage something connected to the VCC rail and the now wrong load pulls the SMPS over the limit.
Could you show please a screen shot using the other SMPS? What are Duty max and Duty cycle (min, max)?
73, Ludwig
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Steve & Group: I tried the suggested AGC settings (below) and keying has clicks. Tried again with SAMPLE BLOCKS 2 and no changes. I'm back on AGC OFF. Thanks & 73 Jay W6CJ
Parameter | Value |
|----------------------|-------|
| AGC | ON |
| Threshold S | 7 |
| Slope dB per dB | 60 |
| Noise filter | 5 |
| Hang time | 30 |
| Smooth samples | 50 |
| Recovery dB/s | 50 |
| Sample blocks | 4 |
| S9 sounds like S | 9 |
| AGC display | ON |
| AGC dB per bar | 3 |
Thanks for all the suggestions... The key clicks are virtually gone after using the AGC settings from /g/QRPLabs/topic/104712439 . Thanks for the info on 600 Hz being the smallest off
|
DuckDuckGo did not detect any?trackers.
|
|
Unable to verify sender identity
|
|
|
|
Thanks for all the suggestions... The key clicks are virtually gone after using the AGC settings from /g/QRPLabs/topic/104712439 . Thanks for the info on 600 Hz being the smallest offset. Matched with a 600 Hz sidetone, that works for me. Would still be nice to have semi-QSK, with a selectable hold time. 73, Steve, N2IC
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Roger that.
That check can be done but it is a bit complicated and only works if you can? actually hear signals.
First off, bad IF sweeps are a big clue. If one ADC channel has failed then IF sweeps will show no suppression of the unwanted sideband
If the sweeps are just noisy garbage, perhaps both ADC channels have failed.
Going deeper:
Tune in a constant carrier to produce an audio beat note near 700 Hz.
Using the oscilloscope, verify that clean sine waves exist at pin 1 of IC405 and IC406. The signals should be near 12KHz in frequency and 90 degrees out of phase. If so,? the entire RX chain ahead of the ADC is good.
Via the terminal program,? put the QMX in IQ mode and observe the I and Q channels via the PC Audacity audio app. You should see two channels of approximately equal signal amplitude. Otherwise, something is wrong.
JZ
Ok, no harm in trying.?
Before I order the part for the PS Board, is there a way to check if the PCM1804 is good. Save on shipping if I order both at the same time.
It can be done, Cliff. I successfully did one recently. Of course Jeff Moore is there to help!
JZ Ouch! That one looks like it's beyond me to change out. If it proves bad guess I'll give it a go, but ......
Cliff, yeah, I am also concerned that this is not the last layer of the onion that needs to be peeled down.
Overvoltage on the 5V supply rail tends to take out the PCM1804 ADC chip. Its analog front end runs on 5V, the digital portion on 3,3V. It is the weak link of all the devices that run on the 5V rail. That may be the source of the unstable readings you see with the "good" SMPS module.
Keeping fingers crossed...JZ Ok, thanks. I like Mouser an they ship for $5 and I get it next day as they are close to me. I'll look at Digikey.
If this fixes the PS board then I'm puzzled about what else is not right. Fluctuating 5V rail and won't shut down. Hopefully that is an easier fix. Q108 is pretty tiny. Fun to change it.
Ouch! Cliff, I think you found the culprit.? Digikey has the AO3415.
JZ Yes, Q108 is bad. Measurements 20 - 50 ohms.
Next question, looking at Mouser AO3415A doesn't come up. I get a PJ3415 to come up. Is there a better part number?
Agreed, Cliff. That looks OK. Try the same test on Q108. Let's see what we have there.
JZ John,
Drain-Source - Starts out at 10K then charges up to 22K+ (same regardless of +/- orientation, Gate-Drain 110K, Gate - Source 99K. Seems good to me. ?
Cliff , Remove the module from the main board. Locate Q106. Using an ohmmeter, check the resistance at Q106: gate-source, gate-drain, drain-source. All readings should be above 10K ohms. Any reading much less than that suggests a problem.
John,
How would I do that? Checking in circuit and comparing with the good and bad boards they seem very similar in all combinations of resistance measurements.
Duty cycle =0! That means the MCU is doing all it can to throttle back the 5V SMPS and is finding it has no control at all.
Possibly one or more damaged transistors on the 5V SMPS module.
I would check Q106 for shorts.
JZ Ludwig,
The QMX will not boot at 7V. 9V will let it boot so the screen shot if with 9V.
As it sits there the 5V varies up and dow a little. If I go to 10V in it varies up 5.8 or so. On May 29, 2024, at 15:59, DH8WN via ??< DH8WN@...> wrote:
Cliff,
it looks like a problem in the control loop.
How and where did you measure VCC?
If really 6 V and more D108 on board #1 must be broken or disconnected. But this isn't the reason for the high VCC. It's only a lack of protection.
Please show a screen shot of Terminal - Hardware tests - Diagnostics. But use only around 7 V input to protect the QMX. And what is VCC in this situation.
73, Ludwig
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Re: QMX/QMX+ power board issue
Hi, Chris.? PCB#2 was tested according to your posted suggestions- not plugged in.? I thought the current draw might be from a bad regulator or diode, but both of my PCB#2 boards give the same result.? ?I am not sure what I should check next.
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Ok, no harm in trying.?
Before I order the part for the PS Board, is there a way to check if the PCM1804 is good. Save on shipping if I order both at the same time.
toggle quoted message
Show quoted text
It can be done, Cliff. I successfully did one recently. Of course Jeff Moore is there to help!
JZ Ouch! That one looks like it's beyond me to change out. If it proves bad guess I'll give it a go, but ......
Cliff, yeah, I am also concerned that this is not the last layer of the onion that needs to be peeled down.
Overvoltage on the 5V supply rail tends to take out the PCM1804 ADC chip. Its analog front end runs on 5V, the digital portion on 3,3V. It is the weak link of all the devices that run on the 5V rail. That may be the source of the unstable readings you see with the "good" SMPS module.
Keeping fingers crossed...JZ Ok, thanks. I like Mouser an they ship for $5 and I get it next day as they are close to me. I'll look at Digikey.
If this fixes the PS board then I'm puzzled about what else is not right. Fluctuating 5V rail and won't shut down. Hopefully that is an easier fix. Q108 is pretty tiny. Fun to change it.
Ouch! Cliff, I think you found the culprit.? Digikey has the AO3415.
JZ Yes, Q108 is bad. Measurements 20 - 50 ohms.
Next question, looking at Mouser AO3415A doesn't come up. I get a PJ3415 to come up. Is there a better part number?
Agreed, Cliff. That looks OK. Try the same test on Q108. Let's see what we have there.
JZ John,
Drain-Source - Starts out at 10K then charges up to 22K+ (same regardless of +/- orientation, Gate-Drain 110K, Gate - Source 99K. Seems good to me. ?
Cliff , Remove the module from the main board. Locate Q106. Using an ohmmeter, check the resistance at Q106: gate-source, gate-drain, drain-source. All readings should be above 10K ohms. Any reading much less than that suggests a problem.
John,
How would I do that? Checking in circuit and comparing with the good and bad boards they seem very similar in all combinations of resistance measurements.
Duty cycle =0! That means the MCU is doing all it can to throttle back the 5V SMPS and is finding it has no control at all.
Possibly one or more damaged transistors on the 5V SMPS module.
I would check Q106 for shorts.
JZ Ludwig,
The QMX will not boot at 7V. 9V will let it boot so the screen shot if with 9V.
As it sits there the 5V varies up and dow a little. If I go to 10V in it varies up 5.8 or so. On May 29, 2024, at 15:59, DH8WN via ??< DH8WN@...> wrote:
Cliff,
it looks like a problem in the control loop.
How and where did you measure VCC?
If really 6 V and more D108 on board #1 must be broken or disconnected. But this isn't the reason for the high VCC. It's only a lack of protection.
Please show a screen shot of Terminal - Hardware tests - Diagnostics. But use only around 7 V input to protect the QMX. And what is VCC in this situation.
73, Ludwig
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Jay W6CJ