Date   

Re: QCX-mini batch 2 update

Alan G4ZFQ
 

Perhaps we should ask all those who have successfully built these kits to let this forum know, we would then get things in some sort of
Howard,

The problem there is that they do not read about the ones who do have trouble.
They are too busy using the gear:-)

73 Alan G4ZFQ


QCX + 40 HAVING FUN

Stephen Sherer
 

I just wanted to let Hans and the group know how much fun I have been having with the QCX+. I have learned a great deal and am currently building an antenna tuner for 50 watts with a built in SWR meter from an old CB..... and a GTU, ground tuning unit with RF ammeter to maximize RF current through the counterpoise. New antenna build is a12 meter Spyderbeam pole for a quarter wave verticle antenna and a 40m EFHW. The 50 watt amplifier is mostly constructed,  but still working out the details for installing the amp inside the QCX+ enclosure with QRO/QRP menue control .

Does anyone have experience with using the menue for the 50w amp control with relay switches for controlling QRO/QRP power levels?

Would like to hear your ideas...
?



--
KE4LJH
Steve, 
Florida


Re: QCX-mini batch 2 update

howard winwood G4GPF
 

As Hans has already stated, when he designed the original, he had NO problems when he came to testing same.
Perhaps we should ask all those who have successfully built these kits to let this forum know, we would then get things in some sort of perspective.
Now it has become something of a sticking point that some people are using this as a means of covering their own inadequacies.
Hans has taken the probability of failure seriously and has come up with a solution for future kits.
When you are designing something like this, and trying to get a price point where people will buy, and maintain a modest profit. Then picking components ultimately comes down to price as it has to.
Yes! you could make every bit of electronics bullet proof, but it would be so expensive, only the military would be able to afford it.Yes! there appears to be a possible problem with one component, but Hans is doing all he can to react.
Give the guy a break, if you do not like his kits you do not have to buy them.

On 27 Jan 2021, at 17:45, Mont Pierce KM6WT <de.km6wt@...> wrote:

On Tue, Jan 26, 2021 at 09:51 AM, Fred Spinner wrote:
You don't use a 15V absolute max regulator at 13.8V.  You don't need a production test engineer like me to tell you that.  There I said it! 
 
In an actual commercial product those first boards would have been recalled and scrapped. 
Fred, I agree, to a point.

As I've stated some time ago, I would have been scared to death to do 1000 boards on first run, with new design.

I think Hans just got overly anxious to please everyone by shipping before Christmas...
Perhaps an initial run of a few hundred for PCB version 1.0 would have flushed out the issues before going all out.

Anyways, just an opinion, not really knowing/understanding all the ins and outs, in QL's business.

I think a lot of people really had fun, regardless...


What do they say about hindsight?


73
km6wt


Re: Smokey

Mike Besemer - WM4B
 

That's  correct Dan.  If you beat me to it, post some  pictures.

Mike
WM4B


Today, not in the news... an estimated 35 million Pitbulls did nothing but love their families. 

On Jan 27, 2021, at 1:38 PM, Daniel Conklin <danconklin2@...> wrote:
Mike, That's the 78M05 in TO-252, right? I have some of those. I wasn't planning on swapping out, but maybe I'll give it a try. The Zener diode orientation is different on the new board to make a better fit, and I'm not sure if we still need the 10uf electrolytic on the input.


Re: Smokey

Daniel Conklin
 

Mike, That's the 78M05 in TO-252, right? I have some of those. I wasn't planning on swapping out, but maybe I'll give it a try. The Zener diode orientation is different on the new board to make a better fit, and I'm not sure if we still need the 10uf electrolytic on the input.
--
73, Dan - W2DLC


Re: QCX Mini WSPR beacon hangs

KEN G4APB
 

Hi Richard,
this is the effect of loosing the 1PPS calibration timing pulse from the gps module.

73 ken g4apb 


Re: QCX-mini batch 2 update

ohwenzelph
 

I was thrilled to get mine before christmas


Re: Smokey

Mike Besemer - WM4B
 

ALC jack, tuner control, amplifier keying... ad nauseum.

Mike
WM4B


On Wed, Jan 27, 2021 at 01:17 PM, Daniel Conklin wrote:
My point was just to give one example of an audio connector carrying DC. There are other examples, and it is not uncommon to use stereo connectors for things other than audio. The key jack is another example...


Re: Smokey

Daniel Conklin
 

My point was just to give one example of an audio connector carrying DC. There are other examples, and it is not uncommon to use stereo connectors for things other than audio. The key jack is another example...
--
73, Dan - W2DLC


Re: Smokey

Mike Besemer - WM4B
 

LOL Steve... you were probably right the first time!

I've already removed the 1117 and the board is sitting on the bench waiting for Mouser to show up tomorrow.

I planned on trying to document the process... should be fairly simple (he said sheepishly).  I'll know more once I get the new part in my grubby hands and can test-fit it. I'll probably bend the input lead (gently, I hope) of the 78M05 so it floats off the board a small amount.  I may put a bit of Kapton tape on the board where the lead is floating, just to be safe, but the solder-mask is quite good in that area - at least on my board - so I'm not too worried about shorts.  

Fingers crossed!

Mike
WM4B


On Wed, Jan 27, 2021 at 12:57 PM, Steve Z wrote:
I like your idea of shifting the 78m05 one pin to the left to match the ground and output pads of the AMS1117, while tying the input pin to the output of the D3 diode. Once you get this done, please post a description of the process and a photo. We want to learn from your mistakes--  I mean success. :-)


Re: Smokey

kf4pv@...
 

Hans,

While changing the regulator is likely the best solution in this case, I hadn't mentioned that because it seemed to me that it would be more expensive than changing connector. I hope it works out well and that the mini gets past its teething problems. I've thoroughly enjoyed my QCX+ gear (my wife got me a 20m in addition to the 40m I had previously bought for myself) and would love to see the mini be just as successful.

73
Laszlo


Re: QCX Mini WSPR beacon hangs

Richard - N1RBD
 

4.2w with an attenuator on the BNC to bring it down to about 1w to the antenna.


Re: Smokey

Hans Summers
 

Hello Laszlo

Engineering is also about compromises to meet certain targets. In the case of QCX, the targets are high performance and low cost. For QCX-minj, small size also. 

It was an acceptable design compromise to deliver power to the GPS using the 3.5mm stereo jack on the QCX+. With limited rear panel real estate these kinds of compromises were essential. The stereo jack sockets are convenient, commonplace, low cost and PCB mounted. 

It was indeed an error to put +5V on the ring not tip, on the QCX+, because it inevitably shorts the 5V rail to ground when plugged in. +5V should always have been on the tip and this was always my intention; the PTT signal is on the ring on the 50W PA kit, and should have been on the QCX+ also. Then standard stereo cables can be used without needing to cross the wires (swap tip/ring). It was more of a PCB layout error than a design error. The manual describes how to correct this easily with a couple of cut traces and it is also corrected in subsequent PCB revisions although this does create the potential for mix-ups now if people have multiple QCX+ of different revisions. 

I won't be changing the connectors in QCX-mini, I cannot do that and maintain the small size and low price. I have already changed the regulator to 78M05, if is a lot harder to kill a 78M05,  it doesn't fail during intermittent brief current spikes of this nature. So the problem goes away anyway, without needing a change of connector. 

73 Hans G0UPL 


On Wed, Jan 27, 2021, 16:04 <kf4pv@...> wrote:
At the risk of offending someone (which I'm really not trying to do) this is a design error on multiple levels. Stereo plugs are not designed to be power connectors and it was misguided to use them as such. There is also an accepted standard for hot plugging stereo connectors that doing so will not destroy the equipment. This design violates both standards.

Power connectors are designed to prevent short circuits. They are polarized and use separate pins for each voltage and ground. The stereo plug does not fit this requirement. The assembly manual even alludes to it by mentioning the change from the QCX+ boards to try and avoid this problem. In reality, it can never be avoided with a single pin design (and now there is the problem of incompatible connections to the PA kits).

User interfaces have standards, both implied and explicit. This design violates the implicit standard for stereo phone plugs. All our electronic lives we plug and unplug stereo jacks with impunity. Stereos, phones, TVs, etc.  never blow up when you plug in/out headphones or speakers. At worst, they make a loud annoying click. So we are quite thoroughly trained that stereo plugs are safe to plug/unplug under power. Even with a warning label, it's still a problem because that poor label is trying to fight years of training and reinforcement of the user/operator.

The real answer is to fix the design by changing to another connector type. The change can be retro-fitted to some extent by kit builders, though at the cost of some convenience. For example, cutting the +5v trace to the PTT jack combined with Gregg's move to supply GPS power from an external power supply will totally fix the issue. Or, the power trace can be cut and another connector with 2 pins that don't short each other when plugged/unplugged (preferably polarized)  can be used to carry the power separately from the signals.

I realize that QRP Labs is not  a huge consumer products manufacturer and that its target audience is people with a certain level of technical skill so many design processes and methodologies that the big companies use don't apply, but in this case connector selection standards should have been followed. With any luck, the next PCB rev will fix this.

73,
Laszlo



Re: Smokey

Steve Z
 

Mike WM4B:

I like your idea of shifting the 78m05 one pin to the left to match the ground and output pads of the AMS1117, while tying the input pin to the output of the D3 diode. Once you get this done, please post a description of the process and a photo. We want to learn from your mistakes--  I mean success. :-)

Steve N9SZ


Re: QCX-mini batch 2 update

Mont Pierce KM6WT
 

On Tue, Jan 26, 2021 at 09:51 AM, Fred Spinner wrote:
You don't use a 15V absolute max regulator at 13.8V.  You don't need a production test engineer like me to tell you that.  There I said it! 
 
In an actual commercial product those first boards would have been recalled and scrapped. 
Fred, I agree, to a point.

As I've stated some time ago, I would have been scared to death to do 1000 boards on first run, with new design.

I think Hans just got overly anxious to please everyone by shipping before Christmas...
Perhaps an initial run of a few hundred for PCB version 1.0 would have flushed out the issues before going all out.

Anyways, just an opinion, not really knowing/understanding all the ins and outs, in QL's business.

I think a lot of people really had fun, regardless...


What do they say about hindsight?


73
km6wt


Re: U3S fw 3.12 no heartbeat no cal

jakob@...
 

Check if the 1PPS 2ignal gets through the MCU at pin 28. Maybe it is just a wiring issue between the GPS module and the main board assembly.
A oscilloscope or even a simple analog voltmeter can be used for this.
73 de Jakob, AA0JR


Re: QCX-mini batch 2 update

ohwenzelph
 

Checking the 3rd line on the opa2277’s on my uSDX, the ones that I can still see, none of them match any of the others. So 8 out of 8 the code on the 3rd line is unique


Re: QCX Mini 40 Issues

Alan G4ZFQ
 

i checked the 20 meter crystal with scope and show 20 mhz.  I also listened for it on my shack rig with no luck.
Gary,

To hear it on a receiver you would most likely need a short wire antenna put close to the crystal.

I checked solder connections around it.  Swapping displays with my 20 mini I get the same results, only top row of squares.
This is putting the good mini display in the defective mini?

If so then check all connections between the display and IC2 for continuity. Apparently you have done that. Are the voltages the same at the LCD and the corresponding pin of IC2? Are all solder joints good including plug and socket? No shorts? Look again, resolder.

There is very little it can be, you only need to look at this small part of the circuitry.
There is always the chance of a defective LCD.

73 Alan G4ZFQ


Re: Smokey

Mike Besemer - WM4B
 

LOL!

On Jan 27, 2021, at 11:26 AM, "Daniel Walter via groups.io" <yahoo.com@groups.io target=_blank>nm3a=yahoo.com@groups.io> wrote:
Mike, I was thinking about having a 7805 and a limiting resistor. (I'm a 'belt and suspenders' kind of guy!)
--
73, Dan  NM3A


Re: Smokey

Daniel Walter
 

Mike, I was thinking about having a 7805 and a limiting resistor. (I'm a 'belt and suspenders' kind of guy!)
--
73, Dan  NM3A