Re: #QMX Are these Issues?
#qmx
And apparently D102, too. :-(
On 8/24/23 18:14, Paul - AI7JR via
groups.io wrote:
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I think I found it! R104 is missing on the PS board! Must've
gotten knocked off when I was using the air gun to demount
Q103...
Have to look at my resistors, now!
Paul
On 8/23/23 22:06, Paul - AI7JR via
groups.io wrote:
Is there some kind of log for QMX issues? Don't want to bore
anybody by reporting what's known, or my build defect!
Here's what I'm seeing (I've got Firmware version 9 loaded,
7volts, 250ma current limit):
- On application of power, initial current is 0, but goes to
around 10ma after 10-15 seconds. Stays steady after it comes
up.
- On initial power application, power on click is ignored,
until the above 10ma step in current.
- At that point, power on click "delays" for ~10sec, then
display comes on and 150ma current draw.
- Tune knob frequency only goes up?
- Long press power click displays Shutdown, but LCD never
goes off, current (150ma) never drops.
- While "Shutdown" is displayed, band and mode can be
changed!
- Going back to 3, if the power is interrupted briefly
(maybe 200mS), device turns off. Pressing power-on click
activates immediately!
I what I'm seeing "normal" at the moment? :-)
Haven't gotten so far as to transmit or receive, either one.
(Need to read that operations manual!)
Please forgive if this is the wrong place to put this!
73, Paul -- AI7JR
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One thing that comes to mind when comparing the inductive spike at the drains between the TN/VN*06 and the BS170 - you saw a 120V spike with the former compared to 60V with the BS170 - is that the BS170 is not turned on all the way with a 5V drive while the *06 devices are more strongly turned on due to their lower gate thresholds. This was the primary reason I suggested the *06/*10 FETs. The lower gate threshold of the *06 FETs results in a higher drain current which builds a larger magnetic field in the inductor and therefore a larger inductive kick when the FET turns off. Regardless of what physical limitations in the BS170 are clamping the spikes at 60V, the *06 devices will produce a larger spike and will also produce more power output because they’re simply better switching transistors than the BS170 for the existing PA design. They also dissipate less power than the BS170 because Vds is smaller when they’re on. In any event, I certainly would not recommend allowing a spike over 60V so the clamp diode is a good addition. Long story short and with all other things being equal, the TN/VN*06 transistors are better suited to the existing PA design than the BS170. Others on this forum have found this swap to be very beneficial and I’ve yet to hear a complaint of any *06 devices blowing.
Tony - AC9QY
The diode is a good idea I think. Thisis based not only on simulation but on measurements I have made with my scope.
In my case, the loss of two or three sets of BS170 in my two QDX units led me to try different transistors. I ran the other transistors without any failures we for months. But I was curious why the BS170s would fail and the TN0106 and VN0606 would not. Yesterday
I got a new scope that allows me to see transients and I decided to look at the QDX with VN0606 transistors in it. To my surprise, the glitch at the end of a transmission was over 120 volts measured at the center tap. The transistor drains were similar. The
spike was 100ns wide at the 60 volt level. And this is into a dummy load. The transistors must just be capable of dealing with this.
I then replaced the transistors with BS170s and discovered another surprise. The spike was below 60 volts and had a broad flat (but ragged looking) top.?
Then I added the commutating diode and the spikes were gone.?
Right now my theory is that the BS170s are operating in a "make before break" mode which minimizes the di/dt. The VN0606 (and TN0106) might be in the "break before make" mode. The specific operating conditions might possibly allow the circuit to move between
these two cases and the BS170s are just not capable of handling the over-voltage spike while the other transistors can. Just a theory mind you. I have not tried yet to make measurements to verify this. Prior to these measurements, I was thinking that the opposite
would be the case, thus explaining why the VN0606/TN0106 did not fail.?
In any case, I am now running with BS170s again but with the diodes installed. We shall see how long this lasts.
Tony
AD0VC
Simulations are here:
/g/QRPLabs/message/105254
JZ
On Mon, Aug 7, 2023 at 8:07?AM John Zbrozek < jdzbrozek@...> wrote:
>
> Hi Pierre,
>
> The diode simply is in parallel with the 47uH inductor L14, with the
> orientation shown in the photo provided by Paul W9AC. Cathode towards
> the power supply connection, anode to the transformer center tap.
> Any of the diodes he mentioned? (1N4448, 1N4148, 1N914) will do a fine
> job of absorbing the end-of-transmission voltage spike it produces.
> I have used a 1N914.
>
>
/g/QRPLabs/message/105256
>
> Here you can see simulations with and without the diode present.
>
> On another thread, Evan, Hans and I explore the ability of QDX to
> withstand SWR. It seems to have a reputation for SWR intolerance but I
> think there is a case that the problem may actually be as described
> above.
>
>
/g/QRPLabs/message/106759
>
> Regards, JZ KJ4A
>
> On Mon, Aug 7, 2023 at 7:46?AM Pierre FK8IH < jb.gallauziaux@...> wrote:
> >
> > Could you please elaborate: what diode, how did you connect it? A handmade schematic and a photo would be nice.
> > 73
> > Pierre
> > FK8IH
> >
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Re: USB Device not recognized .... another one
#qmx
Rick,
That would make a difference. I assume you also don't have 5V VCC nor 3.3V VDD then
But back to the "no USB" :
Looking at the USB connector pins in your picture, I would say at least 2 pins need to be re-soldered.
Having the pin contact the via barrel and soldered to the barrel is fine but those 2 appear to be really centered in the via barrel hole and the pins are quite small (and short). This will vary from USB connector to USB connector since the locator pins have room to move a little during assy.
What I would recommend is use solder flux (flux pen) and carefully touch each pin (maybe use a toothpick) then use a bit of solder. What you want to do is have the surface tension of the solder to the pin/via barrel draw the solder into the via barrel. Use very little solder and check for unwanted shorts between the surface pads.
Only?SOME?of the USB pins are actually used so you might assume it's OK......but it depends on the pin.
73 Kees K5BCQ
73 Kees K5BCQ
?
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Re: #QMX Are these Issues?
#qmx
I think I found it! R104 is missing on the PS board! Must've
gotten knocked off when I was using the air gun to demount Q103...
Have to look at my resistors, now!
Paul
On 8/23/23 22:06, Paul - AI7JR via
groups.io wrote:
toggle quoted message
Show quoted text
Is there some kind of log for QMX issues? Don't want to bore
anybody by reporting what's known, or my build defect!
Here's what I'm seeing (I've got Firmware version 9 loaded,
7volts, 250ma current limit):
- On application of power, initial current is 0, but goes to
around 10ma after 10-15 seconds. Stays steady after it comes
up.
- On initial power application, power on click is ignored,
until the above 10ma step in current.
- At that point, power on click "delays" for ~10sec, then
display comes on and 150ma current draw.
- Tune knob frequency only goes up?
- Long press power click displays Shutdown, but LCD never goes
off, current (150ma) never drops.
- While "Shutdown" is displayed, band and mode can be changed!
- Going back to 3, if the power is interrupted briefly (maybe
200mS), device turns off. Pressing power-on click activates
immediately!
I what I'm seeing "normal" at the moment? :-)
Haven't gotten so far as to transmit or receive, either one. (Need
to read that operations manual!)
Please forgive if this is the wrong place to put this!
73, Paul -- AI7JR
|
Re: QMX - smoke - another C107/Q108 failure
Razvan said : "... the 5V rail would come alive before the 3,3V would do. But latch-ups are not harmfull, so if you do not have an answer to this question, just forget it: I will find it."
Dear Razvan,
The latch up phenomenon that CMOS components exhibit is much more dangerous than that and is to be avoided!
It's effects are unpredictable, ranging from the harmless and resettable condition that you mention to the full? destructive meltdown of the affected component, having made a massive short circuit between supply rail and ground!
Everything depends on the regenerative gain of the parasitic SCR that is intrinsic to the CMOS structure, and of the level of the current that is? being inappropriately injected into that SCR.
Modern CMOS circuits and processes have been engineered with latch up avoidance as an objective, and they have some forgiveness. Risks remain however. The processor in QMX for example has many pins that can "eat" an injection current of up to 5 mA without latch up or other damage. Some of the pins on that processor have zero tolerance for injected current!
Just an FYI, Razvan.
Wishing you well, JZ KJ4A?
On Thu, Aug 24, 2023, 5:38 PM DL2ARL < dl2arl@...> wrote: On Thu, Aug 24, 2023 at 01:46 AM, Rick Crowther wrote:
I meant only to rig up temporary linear supplies on my bench
hello Rick, Hello Hans,
this is exactly what I was aiming for myself: a temporary replacement of the smps boards until all other smoke tests have been succesfully passed.
Hans: really no offence intended! I am of an older school and do not trust these new-age gadgets piloted by software, not because of paranoia, but because of the fact that they do not belong to my trusted analog world. I find the ideas standing behind the SMPS concept of the QMX most refreshing and innovative: this is the main reason I am glad of having purchased a QMX, without having been in need of yet another qrp toy.
But now.. I am sort of discouraged by my own courage and would like to go one step behind into those quiet linear waters I am used to. Not for good, but at least for the first current intake of the fine rig. Afterwards, having thanks to Chris a test checklist for the SMPS boards outside the rig, without danger of damaging the main professor, I would maybe gain some courage and "replace the linear replacement" with it's new age microprofessor controlled switching PS.
This is what I meant. You might help by telling me if this is doable or if I am to expect some latch-up phenomena during power-up due to the fact that the 5V rail would come alive before the 3,3V would do. But latch-ups are not harmfull, so if you do not have an answer to this question, just forget it: I will find it out by myself.
Yours friendly, Razvan dl2arl?
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My off grid computer uses BK TimeSync and a USB GPS.
I find that it works very well. I exclusively use it every time. My computer is turned on whether it is on line or completely off grid.
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Re: New QRP-Labs product idea? A QMX/QDX based digimode / cat interface?
The Microham USB interface III driver/configuration program works fine on my W10 machine.
Gary
W9TD
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Steve I use dimension4 with Win10 and Win11. No problems.
73
Barb WB2CBA
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Wayne,
I noted that you have disallowed applications from using the QDX audio card:
Change the "Don't Allow"
73
Evan
AC9TU
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QMX - TX shift thrshld bug?
I think there's a bug in the "Configuration --> Digi interface --> TX shift thrshld" entry field.? It defaults to '500' (milliHertz), but no more than two digits (00-99) can be entered from the terminal or directly.
This is with firmware versions 006 and 009, at least.
73,
? Dan
? N7SHM
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Re: USB Device not recognized .... another one
#qmx
On Thu, Aug 24, 2023 at 01:06 PM, Rick Williams - VE7TK wrote: oops .....
So for some reason Q103 and Q105 are NOT being turned on
? -- 73, Rick VE7TK Website:
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Hey, Cliff. So, the gnd hole you spotted doesn't have anything in it. It must just be the way it looks in the photo. For getting audio in, I followed someone else's advice and reloaded the firmware. I then got transmit via putty and now I am getting audio in. I've gotta another piece to this puzzle, though. A friend of mine built a QDX a few weeks ago. His works, so he broight it over for me to try. Guess what? It doesn't work on my computer. I'm seeing the same fail with it as I do with mine. So, I'm thinking my problem isn't with the radio. It is something with my computer. I tried changing the USB cable out, but that didn't change anything.
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Steve, Dimension 4 works with Windows 10.
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Re: QMX - What are my options?
Consider yourself invited to do so.? Hans will do the build as previously agreed.? I will make one addition.? See September QST page 33. I have downloaded the software.? Your past kindnesses has not been forgotten.?
HIF
On August 24, 2023, at 5:03 PM, "Jeffrey W Moore via groups.io" <jeffreymoore@...> wrote:
I can take a look at it for you if you want. ?I’ve fixed about 20 of the QMX rigs for other hams.
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Glad to hear it, Karl! Good luck with the flea sized solder surgery! :D
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Wayne,
L12 is for receive BPF so it shouldn't affect Tx. Of course make sure the blob isn't hitting something else that it shouldn't be. In the first photo it looks like solder in the "GND" pcb hole between the trifilar and L12 toroids. It's probably just and illusion, but that hole shouldn't have anything in it.
Just curious, what did you do to get Rx working now??
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Does anyone have an idea what role L12 might have as it relates to my problem. I had a bit of trouble getting that one wound, but I did finally get it. I do, however, have a small tower of solder that came from the bottom of my board where I soldered it. I believe it's the first tap.
<dummyfile.0.part>
<dummyfile.1.part>
<dummyfile.2.part>
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Does anyone have an idea what role L12 might have as it relates to my problem. I had a bit of trouble getting that one wound, but I did finally get it. I do, however, have a small tower of solder that came from the bottom of my board where I soldered it. I believe it's the first tap.
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Thanks for that info! I downloaded and installed the latest and found the QRP Labs radio config. No, it didn't fix my problem, but it was certainly worth a try.
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I have several of the ViFly for my FPV drone hobby builds. Hadn’t considered using one in the application but I bet it would work great. It trips very quickly, but I haven’t measured the exact time.?
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Ok. What happens after the CAT test and you push PTT, does it turn red? Another click on PTT turns if off.
Tested your radio config and it works FB here. FYI, if you have the latest Wsjtx there is a rig option for the QDX that will let you use Split operation by selecting Rig rather than None. It's called QRPLabs QCX/QDX. You might try that. I doubt it'll fix the problem, but it's setup especially for the QRPLabs rigs so you might want to use it.
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Certainly. Here are my setup pages for Radio and Audio. When I test the CAT, the button does turn green. I am able to change frequencies through WSJT-X.
<dummyfile.0.part>
<dummyfile.1.part>
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Paul - AI7JR
Gary W9TD
Barb WB2CBA
Rick Williams - VE7TK
Leland Lannoye, W9HIF
Luke Williams