Re: QMX+ Upper row of display turned to blocks - failed display? help!
Thanks. Started poking around the pot That was not it! ? Further poking showed that it was very slight pressure from the Ear & Mic/paddle jacks as they exited the front panel which was causing a disconnect in one or more of the header pins for the front panel. Will use a tapered reamer later, to open up the clearances.
All good now - CQ'd on 10 / ft8 ? Got a rely from SP6ZJP - in Poland within 3 minutes. ?from Sandy Hook CT - home made 1/4 vertical and I'm down on a valley!
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Yes, pin 1 and 2 are connected and 3 and 4 are connected. When you press the switch then all four pins are connected to each other.
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If I understand the diagram correctly, it looks like legs 3/4 are connected together and when you press the switch it closes legs 1/2 ??
Is that correct with a switch marked Circuit ??
??? = ? ? ?
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Lasse
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Re: New QMX Rev 3 / High Band - Holiday Project failed after FW Install
Dear Even, thanks so much for the prompt reply.
I have run there tests on PCB #2 (3.3V) as this is suspicious as of the low resistance between VDD and GND.
Running the 1st test 5.6V on?+12V pin and 100mA current limit, my power supply runs into current limiting. Resistance between?+12V and GND pin is about 195kOhm, but still the output VDD is almost short (about 300 Ohm see graphic of measurement) as explained in previous Email. For comparison I measures resistance of a 3.3V SMPS board (for) QMX+ and the resistance is about 150kOhm on the "good" board. This would explain the 100mA current limit is triggered?
Running 2nd test: stops output (no current flow)
Running 3rd test 100% duty cycle: running in current limitation of my lab power supply
Is it correct that this result indicate a broken D109?
IF D109 is the problem, than removing D109 should make the test running OK? Still concerns, ripping of parts that I even can't replace myself: Hans keeps on explaining it's extrem rate to blame the parts. Still no clue what the root-cause of the initial failure is/was.
Have checked the connections at least 10 times (before and after applying power for 1st time): all pins seem to be connected correct and could not find shorts.
As I can't solder SMD, just in case what Diode would be good for replacement. As Mouse and Co apply a hight shipping fee I found this (still expensive) 3.6V 0.5W:
Any chance to verify the rest of the project is running VDD direct from V3.3 from power supply, or would I cause some damage? With 3.3V I only can see the digital section, any chance to run some analysis? I suspect USB and Display run on 5V rail and would be turned off.
Thanks again and best 73 DE Thomas, DJ1TF
Am So., 5. Jan. 2025 um 11:19?Uhr schrieb Evan Hand via <elhandjr= [email protected]>:
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Above may help diagnose the issue
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73
Evan
AC9TU
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Re: New QMX Rev 3 / High Band - Holiday Project failed after FW Install
On Sun, Jan 5, 2025 at 11:11 AM, Thomas Fritzsche wrote:
- Have a Rev 1 QMX, should I try to swap in the 3.3V module? What are chance this fails too? So I don't have any SMPS modules?
Thomas, hard to say. You may have success or not.
- Have a QMX+ Rev1 (not yet build), is QMX+ Rev1 SMPS board compatible with QMX (without plus)? The schematics seem same, but at least some resister?
As far as I know the same boards.
Now I don't know how to continue: bricked forever?
I think not.
BUT ?I can't get this diode (or replacement) in again (I'm not a SMD wizard).
Maybe you will find a skilled HAM in the neighbourhood?
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73 Ludwig
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Re: Computer not connecting to newly built QDX
Do you see an unknown device in the device manager on Windows when it is connected?
If so... delete it from the device manager, disconnect the QDX, turn it off, reconnect the USB cable and then connect the power to the QDX.
Windows will try to reinstall the driver itself.
I had a problem once that Windows messed up something with a driver in connection with Windows Update on one of my machines
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Lasse
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It's the switch, it doesn't make the same clicking sound as the other switch
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Thanks for the comments.
I coated the area with flux, heated the blob with my iron and the
excess went to the iron and the cap fell into perfect position.?
The radio then fired up immediately.
72
Charles - NK8O
On 1/4/25 12:49, Stan Dye via groups.io
wrote:
toggle quoted message
Show quoted text
A short across that particular capacitor (C104) will
definitely cause the symptom you are seeing.
It is the main bypass capacitor between the +12V rail and
ground, which will short as soon as you press the power button.
Yes, clean it up, fix it, and you may be good to go...
Stan KC7XE
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Re: Computer not connecting to newly built QDX
Keep us updated .... Hope springs eternal in the world of confusers :)?
On Sat, Jan 4, 2025 at 10:53 PM, Karl via groups.io <karlshumaker@...> wrote:
Karl,
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Just a rookie here, but . . . a couple of quick questions and comments.?
(1)
Are you saying you are having a similar 'connect' to the PC issue and that your QDX is fast flashing followed by slow flashing when you power it up?
If so, isn't that the indication that the unit is in firmware update mode?
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If I'm right, then there should be a new 'USB Drive' showing up on your PC. If I'm recalling correctly, it didn't pop-up on its own. I had to find it in the windows file explorer, click on it and then the firmware update window opened and I was able to load the firmware.? Pretty well explained in the Operations Manual.
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(2)
Also. You noted your unit is a Rev3b. I wasn't aware there was a version 3'b' but there was a 3'a'. That version had a specific need to cut an unintentional ground short between a ground via and a capacitor. Instructions for how to remove that are in the 'manual_1_12.pdf' assembly document. I honestly don't have any idea how un un-corrected Rev3a unit would react at initial power-up or in operation (if it could at all). Just happened to remember the warning about Rev3a PCBs that was included in the Rev 5-6 manual that I used.? Based on that, I backtracked in the older assembly listings to see the full instructions on how to go about correcting the fault.
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Hope this helps, or at least doesn't hinder . .?
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73 GREG KI4NVX
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That part about windows file explorer may be exactly what I need! Will advise.
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You are right about getting into firmware update mode with the slow blink, I can get in that mode easily and repeatedly. I also found I can connect without the dreaded "unreckonize" flag popping up. You may have given me a way to "drag" the firmware to something!
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Yeah, I read those instructions...Hans wrote those to people who understand confuser computers...I am caveman with the things.
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73
Karl
KI4ZUQ
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It could be a bad (solder)contact, or a bad switch.
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Re: QMX+ No transmit or receive
Thanks Dave! Well, you are right. You never stop learning. I am much better prepared for the next one now and it looks like so are you.
73s
VY2KW
On Fri, Jan 3, 2025, 6:00 AM David Wilcox K8WPE via <Djwilcox01= [email protected]> wrote: Joel,
I had a similar incident on a QRP Labs built QMX+.? It had lower power output from the factory (3 watts or so which is within spec) and then it had no power output.? I checked T501 and it didn’t look like the wires had taken up solder completely like I want to see. So I reheated that transformer with high heat and longer application. Now I have even higher power output.? So trusting the soldering procedure to burn off the lacquer coating on the wire is a not so good an idea in my opinion.? I would at least scrape some of the coating off before soldering.? And apply more heat for a longer period of time to complete the connection. ?
Just my humble opinion, but with 65 years of learning from my mistakes my method works for me.? ? Be the REASON someone smiles today.
Dave K8WPE On Jan 2, 2025, at 7:48?PM, Joel Macneill via <joelmacneill1977=[email protected]> wrote:
? Hello Chris, hello Ludwig! Wow I've got some interesting news this evening. Those voltages that I said weren't present yesterday, are present today. I can't explain it but I set the radio up on the workbench again this evening and confirmed that there was no voltage at t401 like yesterday, but I did have voltage this evening. And I have the voltage that I need at pins 7 and 9 of IC 403 and at pin 9 of IC 402. I'm not quite sure how to explain this because I didn't do anything to it. When I noticed the voltages were there, I connected the antenna to the BNC and right away I heard a crackle in my headphones. Now I'm getting signal meter deflection and I'm listening to CW on 80 m. I'm going to listen to the other bands as well but I'm also going to go into the area where I last was yesterday and make absolutely sure I do not have a loose connection. Obviously when I was poking around with the meter, something happened. Maybe my trifilar coil could have an intermittent short? I don't know but I'm hoping to find out and I will let you all know. Thanks very much for all of your input!
73s
VY2KW
On Wed, Jan 1, 2025 at 06:14 PM, Joel Macneill wrote:
1) I have continuity from C526 to the anode of each 1N4007 diodes closest to the rear of the radio and from the cathode of?each.?
Joel, thank you very much for your wishes.
I don't understand the thing with the cathodes. To the anode is ok but to the cathode the same time?
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All the five points are related to the LPF section. If TX is working well the LPF section should be also ok.
IC408 pin#5 only has 2.5v. ?(idle receive)
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Sorry, my mistake. 2.5 V is ok.
IC402 pin#9 is 0v,?
IC403 pin#7 is ?0v, pin#9 is 0v
Like Chris wrote: 2.5 V from the voltage devider R401 R402 would be ok.
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IC402 pin#1 0v and pin#3 0v.?
Ok both connected to GND.
That voltage should also be present at the trifilar toroid coil. Perhaps I am not making sufficient connection there or perhaps it's a short?
Later you found this by yourselfe. I think no short. In case of a short it should be close to 0 V AND the same voltage across R402, C406. It's strange to find 0 V at all the three pins to C402 / C403. It means all three windings are affected. It looks like more than one bad connection and / or connecting the windings in a wrong way.
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I hope fixing T401 will be the solution.
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73 Ludwig
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Hi, does anyone know the name of the two push buttons on the QMX+?
The one on my "Menu" lives its own life, i.e. it single and double press (random) when I try to enter the Menu
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Lasse
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QCX Challenge & QCX WARC Party -> New support web page :-)
Hello,
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I have created a website to support these two events. The site is now permanently available.
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For the current month, the days on which the events take place are always displayed.
Then there is a display of cluster spots that contain the word QCX or QMX in the comment text. You only need to create a spot where this is included to appear there. You may then find other QCXies more quickly. The spots are also always available, but only the spots from the last 24 hours are displayed. Please give it a try, right now or at any time, so that I can see if it works.
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73/72 it HNY
Tom
DK3DUA
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Re: New QMX Rev 3 / High Band - Holiday Project failed after FW Install
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Above may help diagnose the issue
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73
Evan
AC9TU
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New QMX Rev 3 / High Band - Holiday Project failed after FW Install
Hi Folks,
finally I used holidays to build a QMX Rev 3 High Band (Q202 swapped by QRP Labs) - Order (82020).
With some minor issues all looked good. Inspection OK. Applied 7v with 250mA current limitation some juice, and could see QMX coming up in PC, I installed latest FW 1_00_27.
All looked good, but now when I start and press left rotary encoder qmx is pulling into current limitation.
I checked resistance and 5v and 12 rail looks ok (as far as I can judge). But 3.3V has resistance of only 300 Ohm.
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I pulled the 3.3V module out of circuit:
- Mainboard has resistance of some kilo Ohm (VDD to GND), could be OK
- 3.3V module has 300 Ohm --> not OK.
Checked zener diode? D109 in circuit and it had about 300 Ohms (both way).
So it could be a failure here or other parts failed, what is more unlikely as I assume D109 is a over voltage protection diode?
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Now I don't know how to continue: bricked forever?
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Many questions:
- Have read some people have desoldered D109. I personally would believe I get it out, BUT? I can't get this diode (or replacement) in again (I'm not a SMD wizard).
My problem is: this Diode has a reason to protect and removing it without being able to restore it is not a clever?
For some reasons D109 failed??
- How to diagnose possible reasons for 3.3V module failure??
? ?- Can I check if the CPU is ok?
? ?- Other important parts?
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- Have a Rev 1 QMX, should I try to swap in the 3.3V module? What are chance this fails too? So I don't have any SMPS modules?
- Have a QMX+ Rev1 (not yet build), is QMX+ Rev1 SMPS board compatible with QMX (without plus)? The schematics seem same, but at least some resister?
Should I better complete give up on QMX Rev 3 and restart QMX+ Rev1 instead (but damn they still have same power SMPS modules)?
- Should I order in QRP Labs shop replacements SMPS modules? ... just notice Hans only sends via DHL Express that is about 18 USD and almost twice as expensive than the 10 USD SMPS modules. Adding Tax this is easy 40 USD for boards that might burn our again if I don't find the root cause of failure.
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VY 73 DE - Thomas - DJ1TF
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Re: May the Morse Be With You
We're working on a successor. There is a bunch of prototypes already both for heltec esp32 v3 modules (as the v2 isn't available anymore), esp32 devkit boards, and modern boards with larger TFT displays. The prototypes also use DAC (resp. codecs to combine ADC/DAC) for clean audio.
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73 OE6HKE
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Hi Stan,
The trigger cable was exactly the same: I changed the power bank only. Thank you for the link - I should use this device in the future.
Cheers and 73!
Ivan SA7MAX
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Thank you Ludwig! I agree with you: a high 400 mA current and an elevated temperature of the rig indicate that something g is wrong with the PA part.?
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73 Ivan SA7MAX
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60-15m QMX Kit build - No RX on 60 through 20
My QMX kit arrived and I built it this weekend.? I must say that this is challenging kit mechanical/tolerances.? Not sure I have the correct stack up on control and display CCAs but the kit went to together and generally functions:
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A couple of notes with regard to build:?
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Electret Microphone lead spacing does not match circuit board holes and bending with great concern of breaking, barely got it soldered in the holes. Encoder leads are fragile and short, especially the ones on the side with two leads is short and fragile.? I broke two of them but was able to solder a wire remnant on and make it work.??
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At any rate the unit powered right up, (set up for 9 VDC) the display, controls, and USB interface worked right off.? ?I am able to receive well on 15 and and I think 17 meters but 60 - 20 meters is not working.? ?When I say not working I get noise and birdies but no reception of actual communication signals when hooked to an antenna. ? This is confirmed by the RF filter plots using the Terminal App.? The RF filter plots show signal levels of -30dB and lower, except they look reasonable on 15 and 17 meters.? ?BPF plots look good on all bands.? I have not yet attempted to measure RF power on transmit as I want to go one step at a time.? I have double checked solder connections and continuity tests and verified as much as possible T401 and L401 (which is two tapped inductors on this version).
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Screen shots attached.? Any recommendations would be appreciated.
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Brien - KE7WB
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RF Filter sweeps
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BPF plots
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Re: Computer not connecting to newly built QDX
USB Cable Tester
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this is the one that I use (simple Go/No Go) but plenty of other options on Amazon or Aliexpress
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https://www.amazon.com/Tester-Fixture-Precise-Charging-Micro-USB/dp/B09322XTB7/ref=sr_1_40?crid=3KLY0N7VN700Z&dib=eyJ2IjoiMSJ9.ysqooUra6eP2d0x7Mpp1fPVuYfOxHokSnjP9bUKVP_OWcY1bfFXtSrhHyEmpB1WaGy3KV0qf6DTDM8cCFb-MEetWU4zaeRm4H2zHcUT6TNBtsYghG2gaiPATtiv00XOpGf6omrOumxM2iGzDS4TMvqqMZIh9LCx5KsEUZpt5QlF15DTE-Izn8nRWzkR2UpUdAshA67uaOfO6ymQnjoWzEcwuiITuT8tXJ9Bx4ECDhclnOjOr3yzez_Kpo4_DtmSzrCQMmG836iyclCg9eWByt4Tef6hHBWJ58217BrdBxEEe4bf9ZRgWSZ0rlxmr-B2zPgkqIF64JRfh5iqAB6FBnCuNq1nK_CektDLVk9APLDv4r_r8k7dKaEuP6h5-IuTQFsibNsXiOQmhUcGS_-JZ_DlCNu2ihGwgpRXKxkCETb0YzmFWic6bfzHaC3cW6itD.80QfBct-_ft3BABQt1kvQ7AJYFw9FLJ6aRVS-H64LZs&dib_tag=se&keywords=usb+cable+tester&qid=1736052745&sprefix=usb+cable+tester%2Caps%2C296&sr=8-40
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Ivan SA7MAX
Brien - KE7WB