|
Re: Gibberish characters appended onto end of Message 1
On Fri, Apr 4, 2025 at 05:53 AM, Braden Glett wrote:
Do you happen to know if there's a list of recognized bugs to be fixed,Hans regularly reads messages posted here, and puts the bugs on his list.? As far as I know such a list is not published.? |
|
QMX quit working
#qmx
#troubleshooting
I have a QMX (80-20) for 12 V that I built last year. It worked fine on FD, and was used occasionally since. A few weeks ago I was running it into a dummy load. Controlled by fldigi. Power was a LiFePO? through a regulator at 12 V with a 1.5 A current limit.
?
After messing around with the fldigi settings until I got it to "transmit" into the dummy load. Output power and input current looked good.? Then I got distracted doing something else. After some time I looked at the regulator and it was showing 6.1 V at 1.5 A out. The radio is on, and the display works, but obviously something is seriously wrong.
?
WSJT-X communicates with it. I can change frequencies and modes.
?
I looked at the back of the main board with my IR camera.? The hot spots appear to be associated with Q507 and Q504.
?
So I've blown it up, but I don't know what I did. Is there a troubleshooting guide? I've opened it up and there's nothing visually apparent.
?
In talking this out I've sort of convinced myself that I have a shorted Q504, drawing too much current and heating up Q507. Does anyone have any better ideas? Is there any way to test this hypothesis other than cutting Q504 out of the circuit and seeing if the excess power draw goes away? |
|
Re: Wiki Page: QMX External Microphone Options
#wiki-notice
Take this one, it's the same.
?
?
73, Rajko DC0IT |
|
Re: ProgRock2 programming??
?Hi Alan,
toggle quoted message
Show quoted text
I measured the voltage on the HC6 socket and found negative .1 volts on one side and zero on the other. All the sockets measure the same negative voltage in the instrument. This obviously isn’t an over voltage issue for the PR2 and maybe the negative voltage killed the one I configured for the frequency I needed. Like I said, it appeared to work for a minute or so, then stopped. I’m not sure what I can do here other than pull filament voltage (tube equipment) rectify it and then put a 5 volt regulator on the rectified voltage. I would do that only on the three crystals I planned to use the PR2. I’ve got plenty of room under the chassis for the extra components but the time needed to get the 5v regulator (I don’t know if I have one handy) just adds time to my solution and in hindsight I may have been better off just ordering the crystals. Thanks, Tom N5AMA On Apr 2, 2025, at 7:12?PM, Tom Smith <n5ama@...> wrote: |
|
Re: ProgRock2 programming??
?Hi Alan,
toggle quoted message
Show quoted text
I measured the voltage on the HC6 socket and found negative .1 volts on one side and zero on the other. All the sockets measure the same negative voltage in the instrument. This obviously isn’t an over voltage issue for the PR2 and maybe the negative voltage killed the one I configured for the frequency I needed. Like I said, it appeared to work for a minute or so, then stopped. I’m not sure what I can do here other than pull filament voltage (tube equipment) rectify it and then put a 5 volt regulator on the rectified voltage. I would do that only on the three crystals I planned to use the PR2. I’ve got plenty of room under the chassis for the extra components but the time needed to get the 5v regulator (I don’t know if I have one handy) just adds time to my solution and in hindsight I may have been better off just ordering the crystals. Thanks, Tom N5AMA On Apr 2, 2025, at 7:12?PM, Tom Smith <n5ama@...> wrote: |
|
Re: RTC battery mistake
Hi Chris,
?
Stan had mentioned about Vbat but I didn’t know where to look. The QMX+ was assembled and the GPS module came already installed. Vdd is linked to VBat which I assume is the pre-assembled default. ?With the rig powered off a probe on Batt and the other on the Gnd (on top of the GPS module) there is no voltage - the battery is installed and shows 3.17V (via the battery connections to the pcb). With power VBat shows 3.27V.
Paul, G8MAD |
|
QMX output is always 2W on all bands
Hi everyone, I built the QMX kit configured for 12V operation (the kit was ordered on 13/04/2024), and while everything appears to be functioning correctly, I'm only seeing about 2W of output power across all bands. Here are some data points and measurements I’ve taken:
I’m not sure where to start troubleshooting this issue. What would be the best way to begin isolating the cause? For context, I have the following test equipment available: oscilloscope, multimeter, bench power supply and another working QRP radio for reference/testing. Please let me know if there’s any other information I can provide to help identify the problem. I’d be very grateful for any suggestions or guidance you can offer. ? Thanks in advance for your help! ? Best regards, 73 |
|
Re: Qmx plus rev 2 not powering up
The controller was not powering up from the beginning only when I bypassed the q102 it started. Than my idea was (thanks Stan :)) to trace why I need to do it and found the the micro was probably pulling down the signal probably from the beguining. Probably There was never a blown q102 and sure not a via or track issue. For me was just disappointing because it never worked properly from the first moment because a controller issue.?
I wanted to know why, other wise would be cheaper just order other board, I just spent time, plus parts, shipments, etc. at the end I still don’t know why this pin 88 on the controller was defect, specifically when the power is supplied the rest of the controller seams to work, this puzzles me. Anyway I live in Germany (Nuernberg) so probably should get a chip from turkey.
73 Azgael
? |
|
Re: Wiki Page: QMX External Microphone Options
#wiki-notice
Alas, the Radtel Speaker-Mic does not appear to be available in the USA from Amazon.
?
73, Dave K3DX |
|
Re: shorted PA on TX, dead SMPSU?
On Fri, Apr 4, 2025 at 09:49 PM, Damon wrote:
with IC204 CLK2 into IC501 is 100% @ 3.3V on pin 4. Not sure yet if IC204 or the main mCPU are faulted,Damon, I wouldn't enjoy the RX. I wouldn't switch on the QMX in this state. Maybe voltage at IC204 is wrong because of IC503 died together with the PA. Best way is to remove IC503 and check output of IC501 and IC502. ?
And if the main mCPU would be faulted you couldn't switch on the QMX.
?
73 Ludwig |
|
Re: shorted PA on TX, dead SMPSU?
Dan, its a bit risky but I did it with success. You may do it on your own risk!!!
Set the supply to 3.0 V and current limit to 200 mA. Remove all subboards and connect the bench power supply direct to Vdd and GND. I guess the voltage will drop. Check all IC connected to Vdd for temperature. If you find one hot or significant warm, his should be the culprit. If no IC is hot increase the current to 300 mA, maybe later 400 mA but not more. But be sure while increasing the current the voltage is not going over 3.0 V.
?
2 Ohm and 0.4 A will produce 320 mW heat, enough to feel it.
?
73 Ludwig |
|
Re: Qmx plus rev 2 not powering up
On Fri, Apr 4, 2025 at 06:33 PM, Azgael wrote:
SO.... now the hard part... disconnect the SPM32 Pin 88 from the LIN_REG_EN! Done.Good job but bad outcome. ?
To replace the STM32 you need one prepared by QRP Labs. If you are located in W you may contact Jeff Moore or else QRP Labs direct.
?
73 Ludwig |
|
Re: shorted PA on TX, dead SMPSU?
My QMX+ died the same way on first start-up smoke test. Perhaps what I have found below may help. You might also want to kill the PA voltage by lifting a wire on L502. ?I did find the known, early manufacturing solder fault on the 5V board. My PA is now crowbarred with IC204 CLK2 into IC501 is 100% @ 3.3V on pin 4. Not sure yet if IC204 or the main mCPU are faulted, more investigation in a couple days. For now, I have the 12v bias on TX turned off in the advanced settings and enjoying the RX. |
Igor
Dick Hanson