Hi all,
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I was trouble shooting a problem with my QCX mini for 20m Rev. 3 board T1.09a
?
When I would push down on the tune rate knob or even? touch the knob to adjust the volume the volume would drop off.?
So, I thought being inexperienced, I had probably made a cold or ineffective solder joint.
I went in and examined the solder joints closely. As I went along I touched them up.
I plugged it in and things seemed much better, however, after? short time I was unable to access the menu. I could pull the power and then re-plug it in and have a short time to access the menu, then it would fail again.
This seemed like a problem that Lidiette, was experiencing. I connected it to a dummy load, but the same thing occurred. I unplugged it.
I took it out of the metal enclosure plugged it in again and suddenly I had access to the menu, no problem for as long as I wanted and the volume problem didn't come back.
So, I thought that perhaps something was touching the metal case.
I had added a jumper wire to gain the battery icon on screen. It was loose.
?
From the construction manual-
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"For normal operation of the radio, if you wish to see a
battery voltage icon on screen, then connect pin 1 to pin 3
of the 4-pin header. This connects the voltmeter input to the
12V supply of the radio."
In trying to repair it I slipped with a small scrapper I was using and took R41 smd off the board. Ouch!
It's 150 ohms, on the top of whats left it says 151.
I've added some attachments I hope they are viewable.? Are either of the check marked resistors an acceptable replacement for R41?
?
Thanks,
?
Rick
KC6UXI
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Michigan QRP Club Zoom meeting invite and report
We had eleven folks at the 26 December Michigan QRP Club weekly Zoom chat. Please join us Thursday January 2nd (and every Thursday) at 4PM Eastern for the Michigan QRP Club weekly QRP Chat where the main topics will be QRP and other ham interests. New hams are encouraged to participate and ask questions. It's fun, it's easy, and it's free. You only need a computer, a smart phone, or a tablet that can connect to the Internet. OR if you can't be close to any of those you can join by audio with any standard phone. Just follow the directions below. No software needs be loaded or installed. Anyone can join and non members are welcome. Details are here: Thursdays topic will be a review of 2025 contests for QRPers and the Michigan Mighty Mite transmitter.
Pete WK8S Ed AB8DF Tom WW8LA Tony W8CDC Bill KU8H Stan WB8QJZ Rick K8BMA Neil N9NL Ernie W3ETE Jim K8JK Casey KC9IH
It was Tom’s first time in the chat. He lives in a condo and uses a QMX rig and a G90 for POTA hunting. He tried to use powered speaker with his QMX but he gets FT8 RF feed back. No feedback with earphones. Why? He has done all the normal stuff chokes, swap cables and power sources.
Tony is looking for parts to fix his TS570 and is negotiating? for a non working working for the parts.Santa got him a new Red Miata . Rick asked if any other Kenwood uses the same part. Tony already looked into that option and no. The part he needs is unique to the TS570.
Jim moved to Florida? from Michigan about 3 years ago. He has built many QMXs for others.
Bill has some snow. He is experimenting with Mag loop antennas. He measures things with a Nano VNA and a Tiny SA. He can not get the impedance low enough.
Ernie too busy doing holiday stuff to doing any hamming or playing with his new KH1.
Casey finally got his new antenna after it was shipped all over the country. HighGain Vertical. 12AVQ
The 160 meters Stew Perry Contest is this weekend.
Pete is workin on his Open QRP rig. Seems like 40 is not working. He did fix the side tone level by changing the resistor value in the audio chain. He just received a couple of Old friend K1SWL arp transceivers. The RES vertical antenna he used last week in a POTA activation had the tripod stainless steel legs sized into the hub housing. The company is replacing them.
Rick has a LDG remote tuner to a vertical. It allows him to krrp the HOA happy and still have a decent outdoor antenna.
Next week MMM and?
The topic for January 2nd will be 2025 contests for qrpers and the Michigan Mighty Mite updates. Anyone can take the floor and ask questions. We will go one by one until all have had a chance to have the floor. Files, pictures and presentations can be shared if you have any. There will be time for comments and questions. Please try to stay muted when someone has the floor.
Thanks Ed AB8DF
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Stan, Guess I won the dummy award of the year on the 1st?day.? The QMX+ was in Digital mode.? Set it to CW and all is well!
Tnx,
Tom KT4XN
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First checks:
1) do you have the QMX+ in CW mode?? It will not react to the key in Digi mode
2) does a 'P' or an 'S' appear on the display after the frequency?? If so, you are in Practice mode or the SWR protect has triggered, and in either of those cases transmit is disabled.? Practice mode can be disabled via the menus, and if SWR protect is
triggering, you have a connection problem with your dummy load.
3) what kind of a 9V battery are you using?? The QMX+ will draw about 1A on transmit, and if you are using a standard 9V alkaline battery, it may be dropping the input voltage very low while trying to transmit, giving a very low output power.? You can
see what voltage the QMX+ sees if you set the display option to show the battery voltage.? Then monitor it during TX to see what is happening.
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If none of these quick-checks is the problem, we have to dig deeper.
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Stan KC7XE
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Re: QMX+ No transmit or receive
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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Many thanks Stan, I will have a carefull check.
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Show quoted text
On 1 Jan 2025, at 21:36, Stan Dye via groups.io <standye@...> wrote:
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The power pins of the QMX+ USB connector are not connected to anything in the QMX+ design, so they should not be pulling any power at all from your Mac mini, so you may have a short somewhere in your assembly, or perhaps a bad USB cable.
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I recommend that you check carefully for accidental solder splashes or bridges near the USB connector on the QMX+, or anywhere in that vicinity.
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First checks:
1) do you have the QMX+ in CW mode?? It will not react to the key in Digi mode
2) does a 'P' or an 'S' appear on the display after the frequency?? If so, you are in Practice mode or the SWR protect has triggered, and in either of those cases transmit is disabled.? Practice mode can be disabled via the menus, and if SWR protect is triggering, you have a connection problem with your dummy load.
3) what kind of a 9V battery are you using?? The QMX+ will draw about 1A on transmit, and if you are using a standard 9V alkaline battery, it may be dropping the input voltage very low while trying to transmit, giving a very low output power.? You can see what voltage the QMX+ sees if you set the display option to show the battery voltage.? Then monitor it during TX to see what is happening.
?
If none of these quick-checks is the problem, we have to dig deeper.
?
Stan KC7XE
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Received a new factory assembled QMX+. Testing with a 9 volt battery.? This is a 12 volt QMX+. The receive is excellent. However, there is no transmit on any band.? Tested into a dummy load with a scope attached.? when operating the key there is nothing.? The
factory Doc indicates all bands transmitted well.? Any thoughts on where to start?
Tnx,
Tom KT4XN
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Re: Release of version 1.2 of ABS solution for QMX+ (Automatic internal antenna tuner, internal battery and internal speaker with audio amp)
#ABS
#ATU
#PSU
#QMXplus
I would also like to be included in a group buy if it happens for 1 unit.? Thanks for your work on this gentlemen!
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Martin, K0MJ
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Re: Release of version 1.2 of ABS solution for QMX+ (Automatic internal antenna tuner, internal battery and internal speaker with audio amp)
#ABS
#ATU
#PSU
#QMXplus
Nico, the final price per unit would be determined by the number of participants, and the related quantity discounts we can get.? But for a ballpark estimate, for the first buy with 35 circuit card participants, and 25 component kit participants, the prices were: Circuit cards from Cal: $38 + $11 postage (to US addresses) = $49 Components from Stan: $40 + $6.50 postage (to US addresses) = $46.50 for a total of $95.50.
With 10 participants, the prices would be a few dollars more for each.? You obviously can choose to get the components on your own (as several did the first time) if you have many of them already and can get the rest at a cheaper price.
But keep in mind Cal and I have not yet committed to another group buy, we will be making that decision over the next several days.? It does consume a significant amount of time on our part to make this happen.
Stan KC7XE
On Wed, Jan 1, 2025 at 6:54?AM Nico Smith via <nicosmith873= [email protected]> wrote: Sorry if it has been said but how much is it per person?
I would like to be included as well.
Rhett -KB4HG I would like to be added to the group buy list for one of the ABS kits.
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Thanks,
Howard Cripe - N0AZ
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Re: QMX+ No transmit or receive
On Wed, Jan 1, 2025 at 09:42 AM, Joel Macneill wrote:
IC402 pin#9 is 0v,?
IC403 pin#7 is? 0v, pin#9 is 0v
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All these pins should be supplied with 2.5V from the R401/R402 potential divider through T401.? There could be several open circuits around T401.
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The power pins of the QMX+ USB connector are not connected to anything in the QMX+ design, so they should not be pulling any power at all from your Mac mini, so you may have a short somewhere in your assembly, or perhaps a bad USB cable.
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I recommend that you check carefully for accidental solder splashes or bridges near the USB connector on the QMX+, or anywhere in that vicinity.
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Re: QMX, one of op-amps self-oscillates at 25 MHz (or picks up the system clock?)
Shirley Dulcey KE1L <mark@...> wrote: (The version without the C has different logic for the enable pins;
don't buy those.) Does it really matter in this particular case, when both enable pins are always enabled (tied to ground)? After asking on a ham Discord I found someone locally who has 74CBTLV3253D118 from Mouser, hopefully it will be OK (and hopefully he gives me a normal price)...
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
> I understood that; you are handling it before >? it hits customers for everything except the? > QMX, however even you having to deal with > a 15% failure rate on a component is nuts > (for you to have to deal with).
Nuts, yes! Welcome to my life.? QMX is the outstanding problem. We will find a solution to that too.?
The QMX boards could be tested with some sort of bed of nails test fixture that provided the appropriate test signals for IC403 couldn't they? Use the CLK2 signal attenuated by R513 with a suitable level and phase shift, then the Rx Audio and Image tests should work.? That's enough to test most of the Rx side on an unpopulated board.
Yeah like my QCX-mini test fixture:
It took me 3 R&D-Weeks to build that. I shudder to think how many actual elapsed weeks it would take me to do that now. Arrrgghhhh. But yes it's an option I'm considering... The complexity and number of test pins could be greatly reduced if looking for one specific fault rather than trying to test every aspect of the entire radio.?
I guess you don't see the PCM1804s until they arrive on boards.? Has your trusted supplier been caught by someone flogging clone ICs?
Nope. That would be too easy... Anyway I have never seen anything other than absolute loyalty in the last 11 years working with my colleague in Shenzhen and I'm sure he would never cheat me. He knows what side his bread is buttered on. Issues further along the supply chain (in other words him being cheated, or suppliers of his suppliers) are harder to be so sure of. A messed up world.?
73 Hans G0UPL 73 Hans G0UPL
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Re: Hans Summers/Brian Churchwell
Sorry to do it this way...
--
73
Karl
KI4ZUQ
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
On Wed, Jan 1, 2025 at 08:52 AM, Hans Summers wrote:
?
QMX is the outstanding problem. We will find a solution to that too.?
?
The QMX boards could be tested with some sort of bed of nails test fixture that provided the appropriate test signals for IC403 couldn't they?
Use the CLK2 signal attenuated by R513 with a suitable level and phase shift, then the Rx Audio and Image tests should work.? That's enough to test most of the Rx side on an unpopulated board.
?
I guess you don't see the PCM1804s until they arrive on boards.? Has your trusted supplier been caught by someone flogging clone ICs?
?
Chris, G5CTH
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Re: QMX+ No transmit or receive
Those connections, (pin 9 ic 402 and pin 7/9 ic 403) are for the trifilar toroid. Supplied voltage is from the VCC. I get 5v at R401 with 2.6v drop across the resistor?and approx 2.3 v (the remainder), left at the capacitor C406. 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? I will have to investigate that. Another typo for you, lol, I pinned out ic402 incorrectly in the last email. Pin #10 (Y0) was .79v, (Y1) 2.3v, (Y2) .71v and lastly (Y3)? .7v. Sorry, too many numbers for my comprehension. lol.?
meant to say pin#5 on IC408
I made some checks of the following as instructed:
IC408 pin# only has 2.5v.? (idle receive) IC402 pin#9 is 0v,? IC403 pin#7 is? 0v, pin#9 is 0v C402 pin#1 0v and pin#3 0v.?
I may have a problem here. I confirmed already this morning that the different LPF fets were turning on. I may have to review my IC spec sheets again but i am pretty sure i selected all the right pins. When i get more time tonight or tomorrow, i am going to confirm. Thanks.
73s? VY2KW
sorry, line 1) has a few words that were supposed to?go to line 2).
Thank you Ludwig!! And a happy new year to you and your family. I actually just saw this now. Lol, I got some time this morning. I tried again to track down a problem in the receive path. This is what i have found so far this morning:
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.?
2) I have good continuity across each LPF to my capacitors (3) in each filter with isolation from the other half to ground for each.
3) I have good continuity from the C509 capacitor to the anode of each 1N4007 diode facing toward front of radio.?
4) When I select different bands, I?can see the source of each FET in each LPF turn on and then off when selecting all the different bands from 160 -? 6m.?
5) I have continuity from C509 to the Drain of Q508 and good continuity from the source?of Q508 to the pin 5? of IC408.
I am definitely?going to check out those voltages you have graciously supplied for me. I greatly appreciate it?because for all I know, you may have taken your radio all apart and spent an hour or two getting me this valuable info. It is great to have top notch help like yours!!!!
73s VY2KW
Joel, sorry for coming back so late. Yesterday a strong cold hit me and gave me my first wish for the new year.
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Your next steps could be
- check some voltages at the output of IC408. One of the pins B1...B8 should have 5 V and all the other less voltage. Which Bx depends on the selected BPF.
- check voltage at pin 9 of IC402 and voltage at pin 9 and pin 7 of IC403. All should have 2.5 V.
- check voltage at pin Y0 ... Y3 of IC402. One of the pins should have 2.5 V and all the other less voltage. Which Yx depends on the selected BPF.
Probe at solder pads connected to these pins, e.g. solder pad to L401, L403, ..., T401 and so on.
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Wish you HNY.
73 Ludwig
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
I understood that; you are handling it before it hits customers for everything except the QMX, however even you having to deal with a 15% failure rate on a component is nuts (for you to have to deal with).
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Show quoted text
On Jan 1, 2025, at 8:52?AM, Hans Summers via groups.io <hans.summers@...> wrote:
To be clear again: I'm saying 15% of the batch of 1000 QMX+ Rev 2 PCBs was rejected during our testing here. The percentage of Rev 2 QMX+ with faulty PCM1804 that reach actual kit builders should be near zero.?
QDX is a similar story. We test for it here.?
QMX is the outstanding problem. We will find a solution to that too.?
So in other words, QDX and QMX+ are purely my own internal problem now. Issues for the kit constructor should be very rare. QMX is still an issue I'm working on and needs to join QDX and QMX+.?
73 Hans G0UPL
Yes, remarkable that the PCM1804 saga continues. I built 4 QMX and one QMX+. Only one had an 1804 failure. First Rev 1 and Rev 3 (mini) had/have no failures. Second Rev 1 had SMPS (5V), then Mplx chip failures. Both replaced and all well. Rev 4 had 1804 failure - replaced and all is well. In fact, that is my go-to mid-band rig for portable operations. QMX+ no problems. In addition, 2 QDXs before had no issues with the 1804s. Both QDXs sold since I have the QMXs.?
--
73, Dan? NM3A
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Re: Hans Summers/Brian Churchwell
Hi Karl
I'll investigate now and contact you off-list about this.?
73 Hans G0UPL
Just had some civilian drop off a large box destined to?
?
Brian Churchwell
350 N Main St Ste 7 Unit 856
Wharton, NJ 07885
United States/AMERIKA
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Tel 8584127789
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Mailed 04 June 2024? Customs Declaration CN22
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You paid $63.02 to ship this to New Jersey! Now it is in West Tennessee! No one else on this road or in towns nearby woul have any idea who Summers in Turkey was but a ham who had built some of your kits!
?
I await your direction as what to do with this. The box has been opened but the careful packing has not been disturbed. No one in this country can get that stuff back in the box neatly as your gang there!
--
73
Karl
KI4ZUQ
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dr operators,
Just finished the qmx plus.
Build for9 volts and try with 8 v initially.
When i connect the usb for fw i get the notice from my mac mini m2 that the usb port uses too much power and apple disconnects.
So i have my qmx device for abt 5 seconds in my finder window.
?
?
Any one has an idea what i can do.
I also tried AUX2 to ground , does not help.
?
?
I have a blank display also after pressing the rot switch long.
As i understand that is ok, first fw.
?
73 hanz YL3JD
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Hans Summers/Brian Churchwell
Just had some civilian drop off a large box destined to?
?
Brian Churchwell
350 N Main St Ste 7 Unit 856
Wharton, NJ 07885
United States/AMERIKA
?
Tel 8584127789
?
Mailed 04 June 2024? Customs Declaration CN22
?
You paid $63.02 to ship this to New Jersey! Now it is in West Tennessee! No one else on this road or in towns nearby woul have any idea who Summers in Turkey was but a ham who had built some of your kits!
?
I await your direction as what to do with this. The box has been opened but the careful packing has not been disturbed. No one in this country can get that stuff back in the box neatly as your gang there!
--
73
Karl
KI4ZUQ
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hanz YL3JD
Karl
Kaufman, Matt - N3AR