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Re: QMX won't power off and odd voltages on Q103

 

I am unable to see the QMX on my computer.?


Changing USB port on QMX

 

I've just inadvertently? connected my QMX to a different USB port on my W11 laptop and it failed to connect the WSJT-X.? What happens is that the different port means that a different COM port is assigned and different USB audio ports.

Is there a way for an individual QMX to retain it's serial and audio port designations if it's moved to a different USB port on the same PC?

What I've found is that a FTDI serial port will do this but most others won't.? It makes things far easier - for the user at least.
And the developer, they stop getting "I can't find my QMX" messages.

Chris G5CTH


Re: QRP antenna tuner?

 

Anyone tried this 4sqrp tuner above 10w spec.


For Sale: Mini-OCX 40m

 

Purchased and assembled by Hans 2021. Worked flawlessly for a few months and then the tuning encoder started locking up Have replace the encoder three times and once again the new encoder will not even change frequencies.

All other functions work.

The towel is flying through the air

$75.00, includes shipping within continental U.S.

Tony


Re: CAT port returns ` ` ` on QCXmini

 

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Thanks everyone for your help. ?I now have CAT control of the QCX mini so I can continue to troubleshoot until I have an LCD display again. ?What I didn’t understand initially was that it wasn’t just about RS232 voltage levels that were preventing CAT access it was also that TTL does not swing to a negative voltage like RS 232 does. ?I inserted a TTL to RS232 converter that I previously purchased for another project and now I have CAT access using FLrig software.

Thanks and 73,
Jerry AC5JM?


On Aug 30, 2023, at 11:51 AM, Jerry Moyer via groups.io <ac5jm@...> wrote:

?
Thanks, I'll try that as well.

-Jerry AC5JM

On Wednesday, August 30, 2023 at 09:16:16 AM CDT, Chuck - K3FLN via groups.io <chuck.salmon@...> wrote:


Putty can be configured to wait for carriage return to send message.? Just set "local line editing" and "local echo" to "force on"?in the terminal options.

<dummyfile.0.part>

--
Cheers,
Chuck
<dummyfile.0.part>


Re: QMX won't power off and odd voltages on Q103

 

Did you load firmware? --n1bs


On Wed, Aug 30, 2023, 2:32 PM PHILIP GRAITCER via <pgraitc=[email protected]> wrote:
We are in a hurricane watch and tropical storm ?watch and tornado watch, so to take my mind off the weather, I am trying to get my QMX, Rev 1 going.

I have set my power supply at 7volts and limited current to 200ma. The unit powers on and the LCD turns on but is blank.Brightness does not change when variable resistor adjusted.

I am unable to turn the unit off with a long press on left encoder. I have to turn off bench supply.

I measured voltage on Q103 with encoder off
Gate 6.93
Source 6.68?

With unit on, the bench power supply drops to 5.2v and 198ma (But I can't turn unit off)
Gate 0.00
Source 4.96

Realizing my first problem is not being able to turn the unit off, I checked and touched up connections on encoder (as usual, the tabs broke off during installation and I used component leads to connect broken tab to appropriate hole).? During assembly I had to remove the 2x4 female header on the main board because it wasn't straight. One pin of the female header remained in the hole. I removed that by hand and slipped it back into the header. I checked for continuity between the top pins on control board and the solder pins of the female header on bottom of main PC board so I assume that the female header is ok.

On the 5V power supply board, I touched up the tabs on the 8 pin female header and checked for any possible shorts between those pins and the source and gate of Q103. I had previously clipped these pins slightly shorter.

With bench supply at 8volts (used a higher voltage to see if that might wake up the board), I measured voltage of the pins on top of the female header of ?5V board. Unable to access four pins underneath the board.? Designating the pin closest to the 1/8" jacks as pin 1, here is what I got:
Pin 1 encoder off 7.92 ?on 5
Pin 2 encoder off 0 ?on 1
Pin 3 encoder off 8.0 ?on 5
Pin 4 encoder off 0 ?on 2.16

At this point I am stumped. There is a short somewhere and/or open connection.?I have little electronics theory knowledge, does anyone have any ideas what I should do or would you like to take a look at my unit? (This is about my 6th QRP-Labs kit.)

Thanks in advance.

Phil, K3UT


Re: QMX won't power off and odd voltages on Q103

 

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One thing, you can't turn the QMX off until you have turned it on.

The turning off process is controlled by the MCU, it sees the long press and does a load of close down housekeeping, saving parameters, closing down things, putting the cat out, then finally turns it's own power supply off.? It's not death, just sleeping.

But from what you are saying the MCU hasn't fully started.? You mention that the power goes to your limit and the voltage drops.? It's less than 5V and too low to get the 5V supply fully active. This means that the MCU may be in the start up sequence waiting forever for 5V on the 5V rail.? It hasn't fully started.

Try increasing the current limit a little, I wouldn't go over 250mA.? See if that helps.? If it doesn't then there's something taking too much current from the 5V supply.? That needs to be found and fixed.? If you can try checking the 5V PSU board separately, maybe something on that has shorted.

HTH

Chris, G5CTH

On 30/08/2023 19:32, PHILIP GRAITCER via groups.io wrote:

We are in a hurricane watch and tropical storm ?watch and tornado watch, so to take my mind off the weather, I am trying to get my QMX, Rev 1 going.

I have set my power supply at 7volts and limited current to 200ma. The unit powers on and the LCD turns on but is blank.Brightness does not change when variable resistor adjusted.

I am unable to turn the unit off with a long press on left encoder. I have to turn off bench supply.

I measured voltage on Q103 with encoder off
Gate 6.93
Source 6.68?

With unit on, the bench power supply drops to 5.2v and 198ma (But I can't turn unit off)
Gate 0.00
Source 4.96

Realizing my first problem is not being able to turn the unit off, I checked and touched up connections on encoder (as usual, the tabs broke off during installation and I used component leads to connect broken tab to appropriate hole). ?During assembly I had to remove the 2x4 female header on the main board because it wasn't straight. One pin of the female header remained in the hole. I removed that by hand and slipped it back into the header. I checked for continuity between the top pins on control board and the solder pins of the female header on bottom of main PC board so I assume that the female header is ok.

On the 5V power supply board, I touched up the tabs on the 8 pin female header and checked for any possible shorts between those pins and the source and gate of Q103. I had previously clipped these pins slightly shorter.

With bench supply at 8volts (used a higher voltage to see if that might wake up the board), I measured voltage of the pins on top of the female header of ?5V board. Unable to access four pins underneath the board. ?Designating the pin closest to the 1/8" jacks as pin 1, here is what I got:
Pin 1 encoder off 7.92 ?on 5
Pin 2 encoder off 0 ?on 1
Pin 3 encoder off 8.0 ?on 5
Pin 4 encoder off 0 ?on 2.16

At this point I am stumped. There is a short somewhere and/or open connection.?I have little electronics theory knowledge, does anyone have any ideas what I should do or would you like to take a look at my unit? (This is about my 6th QRP-Labs kit.)

Thanks in advance.

Phil, K3UT



Fw: [QRPLabs] QMX - sockets for BS170s #qmx

 

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Hans,

For Reference as suggested: From Billy (N5SE), My QMX is still in Turkey!

Graham Whaley wrote on Wednesday 08/30/2023 at 06:32 CSDT titled Re: [QRPLabs] QMX - sockets for BS170s

??????|check out the heatsinking on message /g/QRPLabs/message/108109 |

Looks great to me. Any chance of getting something like this as an add-on to the QMX. Could be worth it.

Thanks, Billy (N5SE}


From: [email protected] <[email protected]> on behalf of Graham Whaley via groups.io <graham.whaley@...>
Sent: Wednesday, August 30, 2023 05:54
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] QMX - sockets for BS170s
?
Aha, I knew I'd seen a photo with pin headers under the BS170's recently - check out the picture of the heatsinking on message /g/QRPLabs/message/108109
Might want to ask Cliff, AE5ZA how that is working out ;-)

Graham, M7GRW

On Wed, 30 Aug 2023 at 11:40, Jerry <Jerryh47@...> wrote:
After repairs done multiple times replacing FET Q9 in my QDX transceivers the pads are getting “tired.” ?I used some small brass tube stock (~1 mm outer diameter) to make eyelets or grommets to reinforce the pads. A short length of the tubing goes through the pad and is swaged with a center punch on both sides of the PCB. They are not sockets but do strengthen the pads so the pads don’t lift off the board so easily after several soldering cycles.?


--
N5SE
Billy Wayne Moore
7066 Shady Knoll Ln
Willis, TX 77318-6324
Phone: 936-537-2975???


QMX won't power off and odd voltages on Q103

 

We are in a hurricane watch and tropical storm ?watch and tornado watch, so to take my mind off the weather, I am trying to get my QMX, Rev 1 going.

I have set my power supply at 7volts and limited current to 200ma. The unit powers on and the LCD turns on but is blank.Brightness does not change when variable resistor adjusted.

I am unable to turn the unit off with a long press on left encoder. I have to turn off bench supply.

I measured voltage on Q103 with encoder off
Gate 6.93
Source 6.68?

With unit on, the bench power supply drops to 5.2v and 198ma (But I can't turn unit off)
Gate 0.00
Source 4.96

Realizing my first problem is not being able to turn the unit off, I checked and touched up connections on encoder (as usual, the tabs broke off during installation and I used component leads to connect broken tab to appropriate hole). ?During assembly I had to remove the 2x4 female header on the main board because it wasn't straight. One pin of the female header remained in the hole. I removed that by hand and slipped it back into the header. I checked for continuity between the top pins on control board and the solder pins of the female header on bottom of main PC board so I assume that the female header is ok.

On the 5V power supply board, I touched up the tabs on the 8 pin female header and checked for any possible shorts between those pins and the source and gate of Q103. I had previously clipped these pins slightly shorter.

With bench supply at 8volts (used a higher voltage to see if that might wake up the board), I measured voltage of the pins on top of the female header of ?5V board. Unable to access four pins underneath the board. ?Designating the pin closest to the 1/8" jacks as pin 1, here is what I got:
Pin 1 encoder off 7.92 ?on 5
Pin 2 encoder off 0 ?on 1
Pin 3 encoder off 8.0 ?on 5
Pin 4 encoder off 0 ?on 2.16

At this point I am stumped. There is a short somewhere and/or open connection.?I have little electronics theory knowledge, does anyone have any ideas what I should do or would you like to take a look at my unit? (This is about my 6th QRP-Labs kit.)

Thanks in advance.

Phil, K3UT


Re: 2nd QMX Build and it wont power on and an update on my old unit...

 

I’ll have to find someone willing to do that, I have the right tools to do it I’m sure including a scope, but I’m just really not that great with a o-scope.?


QMX Menu Suggestions

 

Hans, here are a couple of minor suggestions from the Operations Manual.

4.6 - Frequency Presets - Why not have CANCEL be the EXIT button (rather than the right rotary button) and LOAD be the right rotary button? That would make it more intuitive with the usual function of the EXIT button?and consistent with the Messages selection buttons. I realize that this is currently consistent with the QCX, but I never liked it there either as I usually ended up cancelling rather than loading! I just didn't say anything.

5.14 - Clock Setting - Is there any way to set the clock manually? Might be nice to do, so I don't have to use another device to log QSOs? I normally log on paper and don't drag a GPS unit along for SOTA.

? ? ? ? - Backlight setting - Should be a way to turn the backlight on temporarily for 5 seconds or so, by single button pushes. Along the same lines, it would be nice to have a third setting that normally has the backlight off, but automatically turns the backlight on for 5 seconds or so whenever a button is pressed or an encoder turned (but not when paddles or key are pressed). Don't know that you need both of these things - the latter would work just fine.

5.17 - Factory Reset - Suggest putting the 'Enter 17' system (from QCX) back in place. Although I haven't done it, it would just be too easy to accidentally press the encoder button when you meant to turn it.

--
73, Dan? NM3A


Re: 2nd QMX Build and it wont power on and an update on my old unit...

 

Hello Devan

A technique I suggested for QCX troubleshooting was to bypass the signal generator resistor (120K in QCX, 100K R518 in QMX) with a much smaller resistor, say 330-ohms. Then the signals are enough amplitude that you can trace them through the LPF, BPF and trifilar transformer, with an oscilloscope. Signal tracing, oldest techniques, still valid. I don't think there's a problem in your PCM1804 or digital Signal processing. I'd guess it's in the filters or mixer.

73 Hans G0UPL


On Wed, Aug 30, 2023, 7:17 PM Devan Phillis <devan@...> wrote:
Hans,

The trifiliar was one of the first things we did…. Also, I reflowed all the other places where enamel comes thru the board. I should mention that the 1804 gets warm… not hot but warm. I’ll look back try my emails with John and get an idea of where we were, it has been a while since I had the time to mess with it. I would really like to get the original going because it was one from Dayton and then the new one is obviously not. Also… I made a work around but a heads up, my 2X3 female socket connector was missing a pin. See attachment.


Re: CAT port returns ` ` ` on QCXmini

 

Thanks, I'll try that as well.

-Jerry AC5JM

On Wednesday, August 30, 2023 at 09:16:16 AM CDT, Chuck - K3FLN via groups.io <chuck.salmon@...> wrote:


Putty can be configured to wait for carriage return to send message.? Just set "local line editing" and "local echo" to "force on"?in the terminal options.


--
Cheers,
Chuck


Re: CAT port returns ` ` ` on QCXmini

 

I have a TTL to RS232 converter that was designed to interface directly with Raspberry Pie I/O pins that I will try and let you know.? It should also work in reverse to convert RS232 to TTL.??

Thanks!
Jerry AC5JM

On Wednesday, August 30, 2023 at 08:21:31 AM CDT, Rob Giuliano via groups.io <kb8rco@...> wrote:


On Tue, Aug 29, 2023 at 03:56 PM, David Markovitch wrote:
Besides having higher voltages, a USB to RS232 signal will be inverted compared with a RS232 TTL signal.
Not to mention that TRUE RS232 levels swing + and - at those higher voltages.? So your 6V RS232 logic is very likely switching between +6V and -6V.
There is a good explanation here:??of?

-------
Rob KB8RCO


Re: 2nd QMX Build and it wont power on and an update on my old unit...

 

Hans,

The trifiliar was one of the first things we did…. Also, I reflowed all the other places where enamel comes thru the board. I should mention that the 1804 gets warm… not hot but warm. I’ll look back try my emails with John and get an idea of where we were, it has been a while since I had the time to mess with it. I would really like to get the original going because it was one from Dayton and then the new one is obviously not. Also… I made a work around but a heads up, my 2X3 female socket connector was missing a pin. See attachment.


Re: #qmx QMX and waste heat from the finals #qmx

 

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Wayne,

I had it lying around from a Raspberry Pi 3B that I had put in a different enclosure with different cooling so the heat sink wasn't needed anymore. Wish I had more of them.

73,
Cliff, AE5ZA



On Aug 30, 2023, at 10:55, Wayne Greene <wayne.greene489@...> wrote:

Thanks, Cliff. You've been a tremendous help on this. Where did you find the heat sink you have on top of the finals?

Wayne KB4DSF

On Wed, Aug 30, 2023 at 11:41?AM Cliff <ae5zaham@...> wrote:
Wayne,

There is just a hole through the plate to hold it in place and a foot that you can't see almost at the left hand edge under the plate the same as the one that is visible on the right hand side. It was made from a piece of aluminum molding that happened to have those two feet in the right place. I may try to put a piece of it under the finals on the QMX, but without the feet, as I'm sure there isn't enough room for the extra height of the feet.

I also added the diode across L14 so hopefully it will be as bullet proof as I can make it and baring operator "destructive" testing should last a long time.

Here's the reference from John Z to the diode "fix" in case you are interested.

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

73,
Cliff, AE5ZA



On Aug 30, 2023, at 09:35, Wayne Greene <wayne.greene489@...> wrote:

Hey, Cliff. How did you mount the plate under your finals?

Wayne KB4DSF





--?
Wayne Greene


Re: 2nd QMX Build and it wont power on and an update on my old unit...

 

Hello Devan

The fact that it has noise along there, not flat-lined, indicates to me that the PCM1804 is probably OK. You probably have an issue upstream of that. Could even be toroid enamel... or mixed up windings on the trifilar transformer. But my apologies if you have considered this already.?

73 Hans G0UPL



On Wed, Aug 30, 2023 at 6:57?PM Devan Phillis <devan@...> wrote:
Audio Filter Sweeps



Re: 2nd QMX Build and it wont power on and an update on my old unit...

 


RF Filter Sweeps




Re: 2nd QMX Build and it wont power on and an update on my old unit...

 


Image Sweeps




Re: 2nd QMX Build and it wont power on and an update on my old unit...

 

Audio Filter Sweeps