¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. QRPLabs
  2. Messages
Expanded Topics Messages Polls
Date
Re: QMX Rev3 Board Transformer Continuity Issue

 

Thank you both.? Unfortunately I can't find any soldering issues.? ?I have more wire coming tomorrow as its most likely a winding issue at this point.

73
Re: Disconnect USB after TX

 

Hi Evan,

what do you mean with "SWR trip notification" ? (sorry for stupid qustion)

Today I tested indoor (because of the weather) with dummy load and USB3 instead of USB2 cable and other positioning of the technic. All tests were without any drop. In addition I ordered yesterday some FT240-43 for coax cable of the antenna.

But for sure this does not mean that it is stable now.

Thanks?
Thorsten - DO1TG
Re: QMX Rev3 Board Transformer Continuity Issue

 

Hi Bryan,

In addition to Greg's checks, verify that you do not have a solder bridge around the BS170s or L502.? There is a construction issue somewhere around the PA section.

73
Evan
AC9TU
Re: QMX Rev3 Board Transformer Continuity Issue

 

Nope. The A to B test should be open, no continuity between them.
Double check that the windings are correct and the right wires are in the right holes.


On Sat, Mar 23, 2024 at 12:12 PM, Bryan DeLong K3BRY
<ananon@...> wrote:
I just got my Rev3 board yesterday and I was doing the continuity checks as per the manual on page 31 and it specifies no continuity between the A points and B points but I'm getting a 800 ohm continuity between them?? Is this a concern and if so where should I start looking for an issue.? ?I can't see any solder bridges off hand.

73

Bryan

Re: QMX and WKmini problem-Not sending after OS v 9...

 

Sorry for the delay in responding?

I'm expecting my WinKey mini on Monday. Hoping to get it working with MP40. Never could do Morse in my head,? but I sure can type. I think I read where the WinKey mini will work with CWType and will try that too.?

I've used the MP40 app to read code and it does a remarkable job decoding. Catches a bunch more than the QMX internal decoder it seems. Though, I was surprised at how much the internal reader was getting considering both were contending with a LOT of fading during the poor conditions earlier this week.?

I'll follow up when I get it hooked up.?

Greg KI4NVX?


On Thu, Mar 21, 2024 at 10:12 AM, Mike Carletta
<mike.carletta@...> wrote:
QMX & WKmini Set Up
Terry
I am interested in how you handled the wiring set up?
Could you send a sketch of how your inserted the WKmini between the computer and WKmini module.
I have tried several set ups to no avail.
Mike
K2OI

QMX Rev3 Board Transformer Continuity Issue

 

I just got my Rev3 board yesterday and I was doing the continuity checks as per the manual on page 31 and it specifies no continuity between the A points and B points but I'm getting a 800 ohm continuity between them?? Is this a concern and if so where should I start looking for an issue.? ?I can't see any solder bridges off hand.

73

Bryan
Re: Disconnect USB after TX

 

Hi Thorsten,

The supply listed is adequate based on the supplied power, according to the specification.? It may be noisy as it is a switcher, but otherwise, it should not cause the QMX to drop out.? Are you getting the SWR trip notification when transmitting it to the dummy load?

73
Evan
AC9TU
[QMX rev3 high band] Need help troubleshooting bad AF, RF and Image sweep results

 

Hi all,

I just finished building my QMX rev3 high band and completed all the sweeps in terminal. LPF results are relatively okay, but the results of Audio filter, RF filter and Image are not so good (screenshots attached).

Audio filter sweeps

I noticed 4 issues:
  1. On 17M band, there was almost no attenuation on unwanted sideband.
  2. On 20M, 12M, 11M and 10M, the level of USB was quite low. I was expecting around 0dB, but mine was around -15dB.
  3. The attenuation of LSB was not enough? According to the operation manual, I was expecting about 60dB, but mine is about 50dB?
  4. There were dips around 2.2kHz in USB.

RF filter sweeps

  1. The shape of the filter responses doesn't look like first order filters. In bands other than 20M, the passband didn't have a flat top? The 20M band however had many small dips.
  2. The amplitude of the 20M passband is too low (-13dB). The amplitude of other bands were too high, like +10dB.

Image sweeps

  1. 17M had only -2.2dB which is likely due to the same reason caused the bad Audio filter sweep result above?
  2. 15M, 12M and 11M had only around -20dB instead of -30dB?

My understanding is that these 3 types of sweeps are relatively isolated from the TX path so I can focus on fixing them first before worrying about the LPF, SWR and TX power. I already double checked L401 and T401 which I thought might be relevant to the issues, but they didn't seem to have any issues. Could Hans or anyone please explain to me briefly how these 3 types of sweeps are done and which components are involved? And if possible give me some suggestions which components I probably screwed up that could lead to bad sweep results here? Many thanks!!

BTW, the tests were done with QMX connected to a 3S lipo battery and connected to a laptop. The 3S lipo battery and the USB-C cable were quite short and the laptop was running on battery so RFI could be minimized.

Best regards
N6HAN Zhenxing Han
Re: Disconnect USB after TX

 

Hi Tisha,

thanks for this good tips. I just tried to order one from your link but it seems that this is for company only, because with this order you "request a sample", right?

What is you experience?

?

Hi Evan,

as I m a beginner I bought this power plug wich seems to be ok for the QMX:?

?

73 and many thanks

Thorsten - DO1TG
Re: QMX SWR Measurement tool - please default to current band

 

I've hit that issue too.?
I hope it is on Hans' list.?
Thanks for posting it, Nick.

73, Mike KK7ER?
Re: QMX Immediately shutsdown; safe to apply power w/o control and display boards

 

Very sensible. A self supporting magnifier of some sort is almost certainly needed.? I got a headlamp magnifier thingy at Harbor Freight that actually works great. . Cheap too.? Has LED lights built in. Up to 15X magnification.? Was great for inspecting joints and traces, reading printing on components and replacing an SMD capacitor I managed to break.

Print out the schematics to take with you if you find a willing helper.

G

Greg McCain
gamccain50@...


On Saturday, March 23, 2024 at 10:30:57 AM EDT, Al Simons <al@...> wrote:


Comfortable?? No...? I'll try to find someone locally who has equipment
/ skills that I don't, or at least doesn't shake quite as much as I do.

-Al


On 3/23/2024 07:27, Greg McCain via groups.io wrote:
> Well,
>
> I personally would carefully remove the cap and then check continuity
> between pins 1 and 2 at the LCD display itself.
>
> If it still shows a short, the problem is probably:,
> -- a bridge between? pins 1 and 2 of the LCD solder connections
> --? something in the LCD internals
> -- or possibly something off in the PAD resistor PAD circuit on the
> other end. There's a Vcc feed over there too.
>
> And of course, check the cap itself for a short once it's out of the
> circuit. If it is shorted, that's the culprit.
>
> Good luck. Not sure if you are comfortable with working like that on
> small SMDs.
>
> Greg
>
>
>
>
> Yahoo Mail: Search, Organize, Conquer
> <>
>
>? ? On Fri, Mar 22, 2024 at 11:41 PM, Al Simons
>? ? <al@...> wrote:
>? ? I pulled the trimmer this afternoon, and it shows ~22k as spec'd, and
>? ? the wiper goes smoothly over that range. I don't remember whether it
>? ? went all the way to zero at the ends or not, but I've put the wiper
>? ? mid-range in my testing and it doesn't change the apparent short
>? ? between
>? ? VCC and GND.
>
>? ? I have raised the black pin spacer blocks on JP303 and 304 to make
>? ? sure
>? ? there was nothing extraneous being hidden, but the board is clean.
>
>? ? I tried to pull the jumpers on display pins 1 and 2, to isolate the
>? ? problem to the display board or the carrier board that has the various
>? ? components on it, but I was unsuccessful on getting them unsoldered
>? ? enough to be able to pull the wires.
>
>? ? So of your list, I think we are down to a shorted C301, or a short on
>? ? the display board.? Any other ideas welcome!
>
>? ? Good night.
>? ? -Al
>
>? ? On 3/22/2024 18:59, Greg McCain via groups.io wrote:
>? ? > C301 sure looks like a bypass capacitor for the 5v feed into the LCD
>? ? > board. There to send little spikes and ripples on Vcc (the output of
>? ? > the 5V power supply) safely down the ground.
>? ? >
>? ? > One side of it should have continuity with pin 2 of JP303 (the four
>? ? > pin connector).
>? ? >
>? ? > The other side, I believe, should not show continuity with that
>? ? pin 2,
>? ? > when checked with an ohm meter.
>? ? > And of course, there should also not be continuity directly between
>? ? > the actual contact ends of the capacitor, unless perhaps . . .
>? ? >
>? ? > C301 is indeed shorted . . .
>? ? > OR There is a short between pins1 and 2 on the LCD component itself,
>? ? > OR there is a short through the trimmer resistor (R305)
>? ? > OR? if the trimmer resistor can actually be set to '0' ohms.
>? ? >
>? ? > Can you confirm that the trimmer resistor is? turned all the way
>? ? > counter-clockwise (when looking right down on the top of the
>? ? bugger)?
>? ? >
>? ? >
>? ? > Greg
>? ? >
>? ? > Greg McCain
>? ? > gamccain50@...
>? ? >
>? ? >
>? ? > On Friday, March 22, 2024 at 07:27:20 PM EDT, Al Simons
>? ? > <al@...> wrote:
>? ? >
>? ? >
>? ? > With the display board out of the radio, I measured 0 ohms
>? ? between pin 2
>? ? > of the 4 pin connector (GND), and the pad to the right side of C301,
>? ? > which is marked VCC on the trace diagram. Seems "odd." Possible
>? ? shorted
>? ? > C301? Unfortunately, I have no surface mount skills or equipment.
>? ? >
>? ? > What is a path forward?
>? ? >
>? ? > 73,
>? ? > -Al WA1TYB
>? ? >
>? ? > On 3/22/2024 15:44, Greg McCain via groups.io wrote:
>? ? > > Hopefully something simple and/or obvious.
>? ? > >
>? ? > > Don't forget to check the 2 header connectors on the main
>? ? board too.
>? ? > >
>? ? > > Good hunting. Let us know if you solve it.
>? ? > >
>? ? > > Greg KI4NVX
>? ? > >
>? ? > >
>? ? > >
>? ? > > Yahoo Mail: Search, Organize, Conquer
>? ? > >
>? ? >
>? ? <
>? ? <>
>? ? >
>? ? <
>? ? <>>>
>? ? > >
>? ? > >? ? On Fri, Mar 22, 2024 at 5:05 PM, Al Simons
>? ? > >? ? <al@...> wrote:
>? ? > >? ? Greg, THANK YOU.? Pulling the display board lets it come
>? ? up, drawing
>? ? > >? ? ~150mA at 6V. The terminal program is running, so it seems
>? ? that at
>? ? > >? ? least
>? ? > >? ? part of the CPU is OK.? Now to figure out what I did wrong
>? ? with the
>? ? > >? ? display board!
>? ? > >
>? ? > >? ? Again, thanks.
>? ? > >? ? -Al WA1TYB
>? ? > >
>? ? > >? ? On 3/22/2024 14:36, Greg McCain via groups.io wrote:
>? ? > >? ? > Just a quick thought.
>? ? > >? ? >
>? ? > >? ? > Without the control board will the unit even power up
>? ? since the
>? ? > >? ? rotary
>? ? > >? ? > push to power on won't be available?
>? ? > >? ? >
>? ? > >? ? > You might try just removing the display.
>? ? > >? ? > If the current stays up, then the fault might be in the
>? ? display
>? ? > >? ? board
>? ? > >? ? > or the 5v power board.
>? ? > >? ? >
>? ? > >? ? > I've seen other posts where faults/ bridges/shorts in the
>? ? power
>? ? > >? ? > boards' connector chains have caused odd problems. I took the
>? ? > advice
>? ? > >? ? > in the build instructions and clipped the one set of pins
>? ? back
>? ? > >? ? about a
>? ? > >? ? > millimeter or so because I could definitely see I that a few
>? ? > >? ? were too
>? ? > >? ? > long and extended past the solder pads and awful close to
>? ? other
>? ? > >? ? items.
>? ? > >? ? >
>? ? > >? ? >
>? ? > >? ? > Greg
>? ? > >? ? >
>? ? > >? ? >
>? ? > >? ? > Yahoo Mail: Search, Organize, Conquer
>? ? > >? ? >
>? ? > >
>? ? >
>? ? <
>? ? <>
>? ? >
>? ? <
>? ? <>>
>? ? > >
>? ? >
>? ? <
>? ? <>
>? ? >
>? ? <
>? ? <>>>>
>? ? > >? ? >
>? ? > >? ? >? ? On Fri, Mar 22, 2024 at 2:32 PM, Al Simons
>? ? > >? ? >? ? <al@...> wrote:
>? ? > >? ? >? ? Just completed my Rev 3 QMX assembly. It performs the
>? ? USB stick
>? ? > >? ? >? ? emulation ok, to place the FW file on board. I did
>? ? this both on
>? ? > >? ? >? ? initial power-up and by jumpering AUX2 to GND.
>? ? However, after FW
>? ? > >? ? >? ? load, when I press the left knob it draws power for an
>? ? > >? ? instant and
>? ? > >? ? >? ? then powers back down to 0.000A.? I'm using 7V, limited to
>? ? > 200mA.
>? ? > >? ? >? ? I have inspected all my joints w/ a magnifier, all
>? ? seem fine but
>? ? > >? ? >? ? I'm considering buying a USB microscope.
>? ? > >? ? >
>? ? > >? ? >? ? To start troubleshooting I want to check the power
>? ? boards.? For
>? ? > >? ? >? ? easier access, is it safe to power up the unit without the
>? ? > >? ? control
>? ? > >? ? >? ? board and display boards plugged in?
>? ? > >? ? >
>? ? > >? ? >? ? I've been monitoring this group since I placed my
>? ? order.? I
>? ? > think
>? ? > >? ? >? ? I remember a reference to a troubleshooting guide by
>? ? Hans, and
>? ? > >? ? >? ? another report of this failure mode, but I can't find
>? ? either.
>? ? > >? ? >? ? Pointers to either would be greatly appreciated. I'm aware
>? ? > of the
>? ? > >? ? >? ? troubleshooting log Hans has posted about units he's
>? ? fixed,
>? ? > >? ? but it
>? ? > >? ? >? ? doesn't mention this failure.
>? ? > >? ? >
>? ? > >? ? >? ? Thanks for any advice and pointers.
>? ? > >? ? >? ? 73,
>? ? > >? ? >? ? -Al WA1TYB
>? ? > >? ? >
>? ? > >? ? >
>? ? > >
>? ? > >
>? ? > >
>? ? > >
>? ? > >
>? ? > >
>? ? > >
>? ? >
>? ? >
>? ? >
>? ? >
>? ? >
>? ? >
>? ? >
>
>
>
>
>
>
>






Re: New QMX Rev3 build - no power out...

 

¿ªÔÆÌåÓý

For what it¡¯s worth, my mistake was AFTER probing the pads I clipped a little bit off a few of the connections with the diagonal cutters. Probing should have been the LAST step!

?

73, -Lloyd (wa4efs)

?

From: [email protected] [mailto:[email protected]] On Behalf Of C R Murrell via groups.io
Sent: Saturday, March 23, 2024 10:07 AM
To: [email protected]; [email protected]
Subject: Re: [QRPLabs] New QMX Rev3 build - no power out...

?

The "52 Tips" video by Hans does specifically call out doing continuity checks by probing?

the pad rather than the component lead wire.

?

Charles

?



?

?

?


52 tips for building your QMX successfully!

?

?

On Saturday, March 23, 2024 at 07:48:40 AM CDT, Greg McCain via groups.io <gamccain50@...> wrote:

?

?

Hi Mike,

?

Quick question.

?

Did you do continuity checks on all the toroids by making sure you were probing on the pads of the wire ends or the sides of the solder fillet beads and not the actual wire ends that may be sticking up through the solder fillets?

?

There weren't any specific instructions to do checks? ?in the assembly manual for T507, but you should see 0 ohms between each of the 4 pairs, A-A, B-B, C-C, and? D-D.?

?

?

On Sat, Mar 23, 2024 at 12:49 AM, Michael LaBlanc

<mlablan1@...> wrote:

Fellow QRP'ers,

I just completed a rev 3 QMX build.? I am VERY impressed with level of sophistication of this very small piece of kit.

I'm afraid I have made an error in my assembly and I need to ask this forum for a bit of help in sorting it out.

I am happy to say that I was able to flash the firmware and boot up the radio without a problem.? Also, when attached to an antenna I can clearly hear the sounds from the FT8 frequencies (my unit is the 20-10m model) so the receive parts of the circuit seem like they are functioning.? I am also able to connect to WSJT-X and get good decodes at least on 20m (the other bands may have little traffic right now).

However, I have no power output on the transmit side.? I will attach screen shots from the SWR sweep menu utility, but the measurements are erratic and VERY high (all run on a dummy load capable of 25W).? Also, when I go into the Diagnostics screen and press the "t" button, I get 0 power out, about 9.5 volts and the SWR bounces around between 6 and 10.? This behavior is similar on all bands.

My initial theory is that I have somehow messed up the SWR transformer (T507) and this is causing the high SWR protection software to keep the radio from producing any output.? Before I break out the soldering iron again to pull T507 out of circuit and possibly rewire it, I wanted to get some feedback from those with more experience ?

Thank you in advance for any ideas for further troubleshooting steps or alternate theories about what I have done wrong.

73

Mike
KC2EHR

Re: QMX Immediately shutsdown; safe to apply power w/o control and display boards

 

Comfortable?? No...? I'll try to find someone locally who has equipment
/ skills that I don't, or at least doesn't shake quite as much as I do.

-Al

On 3/23/2024 07:27, Greg McCain via groups.io wrote:
Well,

I personally would carefully remove the cap and then check continuity
between pins 1 and 2 at the LCD display itself.

If it still shows a short, the problem is probably:,
-- a bridge between? pins 1 and 2 of the LCD solder connections
--? something in the LCD internals
-- or possibly something off in the PAD resistor PAD circuit on the
other end. There's a Vcc feed over there too.

And of course, check the cap itself for a short once it's out of the
circuit. If it is shorted, that's the culprit.

Good luck. Not sure if you are comfortable with working like that on
small SMDs.

Greg




Yahoo Mail: Search, Organize, Conquer
<,Organize,Conquer&af_sub1=Acquisition&af_sub2=Global_YMktg&af_sub3=&af_sub4=100000945&af_sub5=OrganizeConquer__Static_>

On Fri, Mar 22, 2024 at 11:41 PM, Al Simons
<al@...> wrote:
I pulled the trimmer this afternoon, and it shows ~22k as spec'd, and
the wiper goes smoothly over that range. I don't remember whether it
went all the way to zero at the ends or not, but I've put the wiper
mid-range in my testing and it doesn't change the apparent short
between
VCC and GND.

I have raised the black pin spacer blocks on JP303 and 304 to make
sure
there was nothing extraneous being hidden, but the board is clean.

I tried to pull the jumpers on display pins 1 and 2, to isolate the
problem to the display board or the carrier board that has the various
components on it, but I was unsuccessful on getting them unsoldered
enough to be able to pull the wires.

So of your list, I think we are down to a shorted C301, or a short on
the display board.? Any other ideas welcome!

Good night.
-Al

On 3/22/2024 18:59, Greg McCain via groups.io wrote:
> C301 sure looks like a bypass capacitor for the 5v feed into the LCD
> board. There to send little spikes and ripples on Vcc (the output of
> the 5V power supply) safely down the ground.
>
> One side of it should have continuity with pin 2 of JP303 (the four
> pin connector).
>
> The other side, I believe, should not show continuity with that
pin 2,
> when checked with an ohm meter.
> And of course, there should also not be continuity directly between
> the actual contact ends of the capacitor, unless perhaps . . .
>
> C301 is indeed shorted . . .
> OR There is a short between pins1 and 2 on the LCD component itself,
> OR there is a short through the trimmer resistor (R305)
> OR? if the trimmer resistor can actually be set to '0' ohms.
>
> Can you confirm that the trimmer resistor is? turned all the way
> counter-clockwise (when looking right down on the top of the
bugger)?
>
>
> Greg
>
> Greg McCain
> gamccain50@...
>
>
> On Friday, March 22, 2024 at 07:27:20 PM EDT, Al Simons
> <al@...> wrote:
>
>
> With the display board out of the radio, I measured 0 ohms
between pin 2
> of the 4 pin connector (GND), and the pad to the right side of C301,
> which is marked VCC on the trace diagram. Seems "odd." Possible
shorted
> C301? Unfortunately, I have no surface mount skills or equipment.
>
> What is a path forward?
>
> 73,
> -Al WA1TYB
>
> On 3/22/2024 15:44, Greg McCain via groups.io wrote:
> > Hopefully something simple and/or obvious.
> >
> > Don't forget to check the 2 header connectors on the main
board too.
> >
> > Good hunting. Let us know if you solve it.
> >
> > Greg KI4NVX
> >
> >
> >
> > Yahoo Mail: Search, Organize, Conquer
> >
>
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_>
>
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_
<,Organize,Conquer&af_sub1=Acquisition&af_sub2=Global_YMktg&af_sub3=&af_sub4=100000945&af_sub5=OrganizeConquer__Static_>>>
> >
> >? ? On Fri, Mar 22, 2024 at 5:05 PM, Al Simons
> >? ? <al@...> wrote:
> >? ? Greg, THANK YOU.? Pulling the display board lets it come
up, drawing
> >? ? ~150mA at 6V. The terminal program is running, so it seems
that at
> >? ? least
> >? ? part of the CPU is OK.? Now to figure out what I did wrong
with the
> >? ? display board!
> >
> >? ? Again, thanks.
> >? ? -Al WA1TYB
> >
> >? ? On 3/22/2024 14:36, Greg McCain via groups.io wrote:
> >? ? > Just a quick thought.
> >? ? >
> >? ? > Without the control board will the unit even power up
since the
> >? ? rotary
> >? ? > push to power on won't be available?
> >? ? >
> >? ? > You might try just removing the display.
> >? ? > If the current stays up, then the fault might be in the
display
> >? ? board
> >? ? > or the 5v power board.
> >? ? >
> >? ? > I've seen other posts where faults/ bridges/shorts in the
power
> >? ? > boards' connector chains have caused odd problems. I took the
> advice
> >? ? > in the build instructions and clipped the one set of pins
back
> >? ? about a
> >? ? > millimeter or so because I could definitely see I that a few
> >? ? were too
> >? ? > long and extended past the solder pads and awful close to
other
> >? ? items.
> >? ? >
> >? ? >
> >? ? > Greg
> >? ? >
> >? ? >
> >? ? > Yahoo Mail: Search, Organize, Conquer
> >? ? >
> >
>
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_>
>
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_>>
> >
>
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_>
>
<,Organize,Conquer?_sub1=Acquisition?_sub2=Global_YMktg?_sub3=?_sub4=100000945?_sub5=OrganizeConquer__Static_
<,Organize,Conquer&af_sub1=Acquisition&af_sub2=Global_YMktg&af_sub3=&af_sub4=100000945&af_sub5=OrganizeConquer__Static_>>>>
> >? ? >
> >? ? >? ? On Fri, Mar 22, 2024 at 2:32 PM, Al Simons
> >? ? >? ? <al@...> wrote:
> >? ? >? ? Just completed my Rev 3 QMX assembly. It performs the
USB stick
> >? ? >? ? emulation ok, to place the FW file on board. I did
this both on
> >? ? >? ? initial power-up and by jumpering AUX2 to GND.
However, after FW
> >? ? >? ? load, when I press the left knob it draws power for an
> >? ? instant and
> >? ? >? ? then powers back down to 0.000A.? I'm using 7V, limited to
> 200mA.
> >? ? >? ? I have inspected all my joints w/ a magnifier, all
seem fine but
> >? ? >? ? I'm considering buying a USB microscope.
> >? ? >
> >? ? >? ? To start troubleshooting I want to check the power
boards.? For
> >? ? >? ? easier access, is it safe to power up the unit without the
> >? ? control
> >? ? >? ? board and display boards plugged in?
> >? ? >
> >? ? >? ? I've been monitoring this group since I placed my
order.? I
> think
> >? ? >? ? I remember a reference to a troubleshooting guide by
Hans, and
> >? ? >? ? another report of this failure mode, but I can't find
either.
> >? ? >? ? Pointers to either would be greatly appreciated. I'm aware
> of the
> >? ? >? ? troubleshooting log Hans has posted about units he's
fixed,
> >? ? but it
> >? ? >? ? doesn't mention this failure.
> >? ? >
> >? ? >? ? Thanks for any advice and pointers.
> >? ? >? ? 73,
> >? ? >? ? -Al WA1TYB
> >? ? >
> >? ? >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>
>
>
>
Re: New QMX Rev3 build - no power out...

 

The "52 Tips" video by Hans does specifically call out doing continuity checks by probing?
the pad rather than the component lead wire.

Charles







On Saturday, March 23, 2024 at 07:48:40 AM CDT, Greg McCain via groups.io <gamccain50@...> wrote:


Hi Mike,

Quick question.

Did you do continuity checks on all the toroids by making sure you were probing on the pads of the wire ends or the sides of the solder fillet beads and not the actual wire ends that may be sticking up through the solder fillets?

There weren't any specific instructions to do checks? ?in the assembly manual for T507, but you should see 0 ohms between each of the 4 pairs, A-A, B-B, C-C, and? D-D.?


On Sat, Mar 23, 2024 at 12:49 AM, Michael LaBlanc
<mlablan1@...> wrote:
Fellow QRP'ers,

I just completed a rev 3 QMX build.? I am VERY impressed with level of sophistication of this very small piece of kit.

I'm afraid I have made an error in my assembly and I need to ask this forum for a bit of help in sorting it out.

I am happy to say that I was able to flash the firmware and boot up the radio without a problem.? Also, when attached to an antenna I can clearly hear the sounds from the FT8 frequencies (my unit is the 20-10m model) so the receive parts of the circuit seem like they are functioning.? I am also able to connect to WSJT-X and get good decodes at least on 20m (the other bands may have little traffic right now).

However, I have no power output on the transmit side.? I will attach screen shots from the SWR sweep menu utility, but the measurements are erratic and VERY high (all run on a dummy load capable of 25W).? Also, when I go into the Diagnostics screen and press the "t" button, I get 0 power out, about 9.5 volts and the SWR bounces around between 6 and 10.? This behavior is similar on all bands.

My initial theory is that I have somehow messed up the SWR transformer (T507) and this is causing the high SWR protection software to keep the radio from producing any output.? Before I break out the soldering iron again to pull T507 out of circuit and possibly rewire it, I wanted to get some feedback from those with more experience ?

Thank you in advance for any ideas for further troubleshooting steps or alternate theories about what I have done wrong.

73

Mike
KC2EHR

Re: QMX Immediately shutsdown; safe to apply power w/o control and display boards

 

Well,?

I personally would carefully remove the cap and then check continuity between pins 1 and 2 at the LCD display itself.

If it still shows a short, the problem is probably:,?
-- a bridge between? pins 1 and 2 of the LCD solder connections
--? something in the LCD internals
-- or possibly something off in the PAD resistor PAD circuit on the other end. There's a Vcc feed over there too.

And of course, check the cap itself for a short once it's out of the circuit. If it is shorted, that's the culprit.

Good luck. Not sure if you are comfortable with working like that on small SMDs.?

Greg





On Fri, Mar 22, 2024 at 11:41 PM, Al Simons
<al@...> wrote:
I pulled the trimmer this afternoon, and it shows ~22k as spec'd, and
the wiper goes smoothly over that range. I don't remember whether it
went all the way to zero at the ends or not, but I've put the wiper
mid-range in my testing and it doesn't change the apparent short between
VCC and GND.

I have raised the black pin spacer blocks on JP303 and 304 to make sure
there was nothing extraneous being hidden, but the board is clean.

I tried to pull the jumpers on display pins 1 and 2, to isolate the
problem to the display board or the carrier board that has the various
components on it, but I was unsuccessful on getting them unsoldered
enough to be able to pull the wires.

So of your list, I think we are down to a shorted C301, or a short on
the display board.? Any other ideas welcome!

Good night.
-Al

On 3/22/2024 18:59, Greg McCain via groups.io wrote:
> C301 sure looks like a bypass capacitor for the 5v feed into the LCD
> board. There to send little spikes and ripples on Vcc (the output of
> the 5V power supply) safely down the ground.
>
> One side of it should have continuity with pin 2 of JP303 (the four
> pin connector).
>
> The other side, I believe, should not show continuity with that pin 2,
> when checked with an ohm meter.
> And of course, there should also not be continuity directly between
> the actual contact ends of the capacitor, unless perhaps . . .
>
> C301 is indeed shorted . . .
> OR There is a short between pins1 and 2 on the LCD component itself,
> OR there is a short through the trimmer resistor (R305)
> OR? if the trimmer resistor can actually be set to '0' ohms.
>
> Can you confirm that the trimmer resistor is? turned all the way
> counter-clockwise (when looking right down on the top of the bugger)?
>
>
> Greg
>
> Greg McCain
> gamccain50@...
>
>
> On Friday, March 22, 2024 at 07:27:20 PM EDT, Al Simons
> <al@...> wrote:
>
>
> With the display board out of the radio, I measured 0 ohms between pin 2
> of the 4 pin connector (GND), and the pad to the right side of C301,
> which is marked VCC on the trace diagram. Seems "odd." Possible shorted
> C301? Unfortunately, I have no surface mount skills or equipment.
>
> What is a path forward?
>
> 73,
> -Al WA1TYB
>
> On 3/22/2024 15:44, Greg McCain via groups.io wrote:
> > Hopefully something simple and/or obvious.
> >
> > Don't forget to check the 2 header connectors on the main board too.
> >
> > Good hunting. Let us know if you solve it.
> >
> > Greg KI4NVX
> >
> >
> >
> > Yahoo Mail: Search, Organize, Conquer
> >
> <
> <>>
> >
> >? ? On Fri, Mar 22, 2024 at 5:05 PM, Al Simons
> >? ? <al@...> wrote:
> >? ? Greg, THANK YOU.? Pulling the display board lets it come up, drawing
> >? ? ~150mA at 6V. The terminal program is running, so it seems that at
> >? ? least
> >? ? part of the CPU is OK.? Now to figure out what I did wrong with the
> >? ? display board!
> >
> >? ? Again, thanks.
> >? ? -Al WA1TYB
> >
> >? ? On 3/22/2024 14:36, Greg McCain via groups.io wrote:
> >? ? > Just a quick thought.
> >? ? >
> >? ? > Without the control board will the unit even power up since the
> >? ? rotary
> >? ? > push to power on won't be available?
> >? ? >
> >? ? > You might try just removing the display.
> >? ? > If the current stays up, then the fault might be in the display
> >? ? board
> >? ? > or the 5v power board.
> >? ? >
> >? ? > I've seen other posts where faults/ bridges/shorts in the power
> >? ? > boards' connector chains have caused odd problems. I took the
> advice
> >? ? > in the build instructions and clipped the one set of pins back
> >? ? about a
> >? ? > millimeter or so because I could definitely see I that a few
> >? ? were too
> >? ? > long and extended past the solder pads and awful close to other
> >? ? items.
> >? ? >
> >? ? >
> >? ? > Greg
> >? ? >
> >? ? >
> >? ? > Yahoo Mail: Search, Organize, Conquer
> >? ? >
> >? ?
> <
> <>
> >? ?
> <
> <>>>
> >? ? >
> >? ? >? ? On Fri, Mar 22, 2024 at 2:32 PM, Al Simons
> >? ? >? ? <al@...> wrote:
> >? ? >? ? Just completed my Rev 3 QMX assembly. It performs the USB stick
> >? ? >? ? emulation ok, to place the FW file on board. I did this both on
> >? ? >? ? initial power-up and by jumpering AUX2 to GND. However, after FW
> >? ? >? ? load, when I press the left knob it draws power for an
> >? ? instant and
> >? ? >? ? then powers back down to 0.000A.? I'm using 7V, limited to
> 200mA.
> >? ? >? ? I have inspected all my joints w/ a magnifier, all seem fine but
> >? ? >? ? I'm considering buying a USB microscope.
> >? ? >
> >? ? >? ? To start troubleshooting I want to check the power boards.? For
> >? ? >? ? easier access, is it safe to power up the unit without the
> >? ? control
> >? ? >? ? board and display boards plugged in?
> >? ? >
> >? ? >? ? I've been monitoring this group since I placed my order.? I
> think
> >? ? >? ? I remember a reference to a troubleshooting guide by Hans, and
> >? ? >? ? another report of this failure mode, but I can't find either.
> >? ? >? ? Pointers to either would be greatly appreciated. I'm aware
> of the
> >? ? >? ? troubleshooting log Hans has posted about units he's fixed,
> >? ? but it
> >? ? >? ? doesn't mention this failure.
> >? ? >
> >? ? >? ? Thanks for any advice and pointers.
> >? ? >? ? 73,
> >? ? >? ? -Al WA1TYB
> >? ? >
> >? ? >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>
>
>
>






Re: New QMX Rev3 build - no power out...

 

Hi Mike,

Quick question.

Did you do continuity checks on all the toroids by making sure you were probing on the pads of the wire ends or the sides of the solder fillet beads and not the actual wire ends that may be sticking up through the solder fillets?

There weren't any specific instructions to do checks? ?in the assembly manual for T507, but you should see 0 ohms between each of the 4 pairs, A-A, B-B, C-C, and? D-D.?


On Sat, Mar 23, 2024 at 12:49 AM, Michael LaBlanc
<mlablan1@...> wrote:
Fellow QRP'ers,

I just completed a rev 3 QMX build.? I am VERY impressed with level of sophistication of this very small piece of kit.

I'm afraid I have made an error in my assembly and I need to ask this forum for a bit of help in sorting it out.

I am happy to say that I was able to flash the firmware and boot up the radio without a problem.? Also, when attached to an antenna I can clearly hear the sounds from the FT8 frequencies (my unit is the 20-10m model) so the receive parts of the circuit seem like they are functioning.? I am also able to connect to WSJT-X and get good decodes at least on 20m (the other bands may have little traffic right now).

However, I have no power output on the transmit side.? I will attach screen shots from the SWR sweep menu utility, but the measurements are erratic and VERY high (all run on a dummy load capable of 25W).? Also, when I go into the Diagnostics screen and press the "t" button, I get 0 power out, about 9.5 volts and the SWR bounces around between 6 and 10.? This behavior is similar on all bands.

My initial theory is that I have somehow messed up the SWR transformer (T507) and this is causing the high SWR protection software to keep the radio from producing any output.? Before I break out the soldering iron again to pull T507 out of circuit and possibly rewire it, I wanted to get some feedback from those with more experience ?

Thank you in advance for any ideas for further troubleshooting steps or alternate theories about what I have done wrong.

73

Mike
KC2EHR

QMX SWR Measurement tool - please default to current band

 

I love the QMX SWR Measurement tool - it is very useful to fine tune the match with my Kanga QRP Pocket Transmatch.

Would it be possible to make it default to the band the radio is tuned to? I have accidentally tuned to 80m (the default of the SWR measurement tool) more than once because I forgot to change the band!

Thank you

Nick M5NCW

--
Nick Craig-Wood <nick@...> --

Re: QMX - Any progress on key clicks please?

 

Daimon,
Try Chris's M0KNF , settings??he put on here earlier.
I finished building my low band QMX and initially had the sidetone clicks. Awful.
With Chris's settings the QMX is now fine on CW, Iambic B, no issues.
I think the crucial setting is to turn AGC off, and then volume down.
Hans, superb instructions, and my advice to builders to carefully scrape off the enamel insulation on every wire end before soldering - it should then work first time!
Rich
G4PCE



On Mon, 18 Mar 2024 at 8:22, Ronan Cantwell
<ronancantwell@...> wrote:
Similar to Steve's findings; I'm quite happily using the radio for CW and have found that any clicks can be tamed substantially by setting the side-tone volume to "relative" and setting its level somewhere in the mid 60's.?

Are the clicks completely gone? No.
Is the radio usable? Absolutely.... (Well, relatively...)

Onwards and upwards.....

Ronan
MM0IVR?

Re: Disconnect USB after TX

 

Hi Thorsten,

Is the power source able to supply 1.5 amps at the supply voltage?? I have had the issue crop up when I forgot to turn up the current limit on my bench supply.

73
Evan
AC9TU
Re: New QMX Rev3 build - no power out...

 

I have not had to troubleshoot the RF side of the circuit but, the most common problem is the enamel on the inductors. Verify that they are stripped and making connection.?
--
Colin - K6JTH?
23921 - 23940 of 141945