Date   

Re: Help needed diagnosing newbuild QCX+

N3MNT
 


Check to make sure the connections between the front panel and the main board are correct  Looks like the connector may be misaligned.  Also check IC4 orientation.
Photos  may help.


Re: Letter 'G" next to frequency

Kyle Krafka
 

I also had this problem recently with a homemade key and a likely-mismatched antenna. I'm still experimenting, but it doesn't happen with a dummy load.


Re: QCX mini died

Dave VE3GSO
 

Perhaps a solution to using a low ESR LiPo battery is to place a low value resistance in series.  Yes, the energy loss goes against everything I believe in my bones, but it might prevent the sudden inrush currents.

Dave

On Jan 23, 2021, at 11:46, Chuck - K3FLN via groups.io <chuck.salmon@...> wrote:

Hi Fredi,
Just in case you didn't know, a fully charged 4S lipo is about 16.8 volts.  A QCX(+) would usually survive it, but not the mini.  I'm sure you will get some good help on how to proceed.
--
Cheers,
Chuck


Re: A word of advice

nz0tham@...
 

I agree and it's not elitist at all IMO.  I have built a lot of kits over the years including an Elecraft K2/100 ad I would not call the QCX series a beginners kit at all.  It's a great design and Hans has done a wonderful job of creating detailed and easy to read instruction manuals but some proven experience in building simpler kits goes a long ways when it comes to building the QCX.   I say this coming from a very non technical education (degrees in Psychology and Business) and career background.  All my electronic knowledge is solely from being a ham for 39 years.

73, Bill NZ0T


Re: Help needed diagnosing newbuild QCX+

Alan G4ZFQ
 

Naturally I have read the troubleshooting sections including the page you linked,
Leo,

OK but you did not say you looked there.
It is essential that that stage is reached. Nothing will work until you have the correct display. There must be something wrong in that little section.
Have you checked the 20MHz crystal?

I do not know how good you are but check the solder joints, one of the most frequent causes of problems.

73 Alan G4ZFQ


which is why I included a reasonably exhaustive list of
actions and measurements taken. Unfortunately the remedial actions had no effect which is why I am asking here.


Re: A word of advice

howard winwood G4GPF
 

I do hope I did not come across as elitist, it certainly was not my intension, mearly to offer some advice to newbies, to avoid too much disappointment when things don’t work.
Whilst there are lots of people who have successfully built their own equipment, I CAN assure you NOT everything works first time.
We are all fallible and can make mistakes, sometimes really stupid ones, it is just that we have built up experience in troubleshooting that allows us to dig ourselves out of the deep hole we have got ourselves in.
That is what differentiates the experts from the beginners.
Please don’t be put off, just have your eyes wide open.
best wishes to everyone

On 23 Jan 2021, at 16:06, R. Tyson via groups.io <tysons2@...> wrote:

Excellent comments. It is obvious that some people are building these kits and have poor soldering abilities, we have seen some of the photos, or little or no experience of construction. The instructions are excellent and the products are excellent. It would be better for someone with no experience to start with some simpler projects. I begin to wonder when I see questions on where to obtain components, that does not indicate any previous experience of constructing. Everyone has to start somewhere but diving straight into a complex project is not necessarily a good idea. Gaining experience on soldering and easier projects would improve the prospects of having a working radio transceiver after assembling one of these kits. Work they do when assembled correctly, are value for money and great fun to use. An experienced constructor will usually have them working first time but that comes from experience.

Reg            G4NFR


Re: QCX mini died

Chuck - K3FLN
 

Hi Fredi,
Just in case you didn't know, a fully charged 4S lipo is about 16.8 volts.  A QCX(+) would usually survive it, but not the mini.  I'm sure you will get some good help on how to proceed.
--
Cheers,
Chuck


Re: QCX mini died

howard winwood G4GPF
 

this is one problem that anyone using a lipo to power ANYTHING, is there ability to supply ridiculous amounts of energy in a very short time.
LiPo’s do not take prisoners.
Dig out the old soldering iron I guess LOL.
you have my sympathy.

On 23 Jan 2021, at 16:18, Fredi HB9BHU <hb9bhu@...> wrote:

Hi
 
I have build my QCX min 20 m Version straight foreward. Super design, super assemlby manual! It was a lot of fun to biuld it - thank you Hans!
I could carry out the alignement exactly as described in the Manual. Ecerything worked fine on my workbench an the laboratory PS; 5W out @ 13,8 V  and very sensitive RX.
But ready for the first SOTAactivation, I plugged in my Lipo 4S battery ... and bang! After first inspection I found a damaged L6 and the LM1117-5.0 has shortet the input to the output :-(!
Despite I followed the instruction to an dditional 100uF capacitor at the 12V input, I it looks like there this is not enough protection if one use a very low impedance voltage source like a LiPo battery! 
Now I afraid, I am ahead of a lot of SMD repair work. Therefore I have two questions:
1.) Has anybody experience with the repair of a dead QCX mini caused by a faild LM1117-5.0, where 13,8 V got fed into the 5 V rail? Is it a better advice to build strsight away a new kit instead of dealing with all those faied comopnents?
2.) Aside from a better regulator like 78M05, is there anything one shoud do externally to avoid high current peaks during power-up, like a coil in series?
 
73 de Fredi, HB9BHU


Re: Help needed diagnosing newbuild QCX+

Leo
 

Thanks.
Naturally I have read the troubleshooting sections including the page you linked, which is why I included a reasonably exhaustive list of actions and measurements taken. Unfortunately the remedial actions had no effect which is why I am asking here.


Re: Puff of smoke, what now?

howard winwood G4GPF
 

Ah! Puff the magic dragon, I think most of us have been there at some point.
My last one was on a self build Quadcopter, a very small ball of solder got flicked off the end of the soldering iron and landed 
on the only place on the main circuit board where it could do any damage, and it did!
The main controller + 4 esc’s all on one board, dead before I could blink.
Sometimes the gods have it in for you, bite the bullet and move on.
Hope you have not done too much damage.

On 23 Jan 2021, at 13:51, N0IIV - Rob Sullivan <rbsllvn@...> wrote:

I'm still not sure what I did wrong but I was trying to test voltage on one of the transistors. Possibly had meter in ohms, not sure. Doesn't matter. Time to move on. I haven't messed with it since the show, but I guess I'll see what I can salvage and order the rest. What is a good source for parts? 


Re: Puff of smoke, what now?

Daniel Conklin
 

Don't give up! You can get it working with a little persistence!
--
73, Dan - W2DLC


Re: Help needed diagnosing newbuild QCX+

Alan G4ZFQ
 

Leo,
Visible symptom: line of black characters at top of display.
Unfortunately you start here. http://qrp-labs.com/qcxmini/trouble.html#blank Most of the rest of your tests need to be done when the LCD is reading correctly.

73 Alan G4ZFQ


There is
the expected seashell whisper in earphones.
Checks performed: ATmega seated okay. Solder joints checked visually and by continuity from lead to pad and pad to next circuit point.


Re: QCX mini died

Fredi HB9BHU
 

Hi
 
I have build my QCX min 20 m Version straight foreward. Super design, super assemlby manual! It was a lot of fun to biuld it - thank you Hans!
I could carry out the alignement exactly as described in the Manual. Ecerything worked fine on my workbench an the laboratory PS; 5W out @ 13,8 V  and very sensitive RX.
But ready for the first SOTAactivation, I plugged in my Lipo 4S battery ... and bang! After first inspection I found a damaged L6 and the LM1117-5.0 has shortet the input to the output :-(!
Despite I followed the instruction to an dditional 100uF capacitor at the 12V input, I it looks like there this is not enough protection if one use a very low impedance voltage source like a LiPo battery! 
Now I afraid, I am ahead of a lot of SMD repair work. Therefore I have two questions:
1.) Has anybody experience with the repair of a dead QCX mini caused by a faild LM1117-5.0, where 13,8 V got fed into the 5 V rail? Is it a better advice to build strsight away a new kit instead of dealing with all those faied comopnents?
2.) Aside from a better regulator like 78M05, is there anything one shoud do externally to avoid high current peaks during power-up, like a coil in series?
 
73 de Fredi, HB9BHU


Re: Cat control query. Qcx mini

morseoneuk
 

Thanks for your comments ,Ian and Wolfgang, I  just don't want to destroy anything...    I will give it a go.    see you all on 60m
Scotty Gi0bey


WARNING: Promotional material

jjpurdum
 

All:

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Jack, W8TEE


Re: A word of advice

R. Tyson
 

Excellent comments. It is obvious that some people are building these kits and have poor soldering abilities, we have seen some of the photos, or little or no experience of construction. The instructions are excellent and the products are excellent. It would be better for someone with no experience to start with some simpler projects. I begin to wonder when I see questions on where to obtain components, that does not indicate any previous experience of constructing. Everyone has to start somewhere but diving straight into a complex project is not necessarily a good idea. Gaining experience on soldering and easier projects would improve the prospects of having a working radio transceiver after assembling one of these kits. Work they do when assembled correctly, are value for money and great fun to use. An experienced constructor will usually have them working first time but that comes from experience.

Reg            G4NFR


Re: A word of advice

geoff M0ORE
 

I have to agree 100%. I have had one kit where there was a problem with the board and I contacted Hans direct on that.

There is no point having a bench full of test equipment if you don't know how to use the results that it gives. No scope will tell you that the fault is due to C???, you have to be able to diagnose the symptoms and test results.

A lot of practice on equipment that is working will build up confidence in the testing, no point learning on a kit that has never worked.

We were all beginners once and have built up our skills over many years. I was fortunate to work in an environment where I had to repair faults ( sometimes after being called out in the early hours ) with the clock ticking and the customer  or control centre breathing down my neck to get the systems back.

Start on the easier kits to build up the confidence and skills.

On 23/01/2021 12:05, howard winwood G4GPF wrote:
Groups like this  tend to be a gathering point for those building and troubleshooting kits offered (in this case) by QRPLabs.
One thing I have noticed, and this applies to a lot off other similar groups, is that there appears to be very little advice on who should/should not be building these kits.
I say this because of the obvious lack of knowledge/skills in even basic electronics that some builder seem to have.
Now, that is not to belittle anyone, we all have to start somewhere, BUT these kits are not really aimed at the beginner for a variety of reasons.
1/ Basic electronic knowledge of components, Ohms law.
2/ Basic soldering skills
3/ Basic set of tools
4/ Basic test gear
5/ Ability to read a simple schematic circuit diagram.
I have noticed on this group and on the microBitx group, that some people (usually with less than even basic knowledge) think these kits (I use the term kit loosely for the microbitx kits) should work with very little effort.
Sadly, as most experienced builders know from experience, this is not the case.
I am going to offer those who may be tempted to get into kit building, some advice based on 50+ years of tinkering with all sorts of electronics, not just in Ham radio.
How do you judge the quality of a kit?
This one is quite simple, look at the documentation.
I will say at this point QRPLabs have some of the best and most comprehensive documentation out there, and would recommend their kits to anyone who has reasonable skills in electronics.
The standard by which kits are judged goes back to the days of Heathkit, superb kits with superb step by step instructions, but certainly not cheap.
So! what level of competence should a prospective kit builder have?
To start with, a basic knowledge of components, resistors, capacitors, semiconductors, inductors.
I would have thought that most radio hams would have this knowledge but it seems I am wrong.
To be able to identify and test resistors and capacitors is a start and to have a basic understanding of their function.
Basic soldering skills are essential, you should not be practising your skills on an advanced kit like the QCX.
After 50+ years of radio building I can still get a bad solder joint, because my eyes don't always pick it up straight away, but I always go over my soldering with a magnifier and ANYTHING that looks suspicious gets a second go.
Basic tools are essential, go for the best quality you can afford, they will last you a lifetime.
a small selection of screwdrivers, side cutters, long nosed pliers to start with.
Some basic test gear such as a Digital Multimeter, and it does NOT have to be expensive. You do NOT have to know the voltage down to the 3rd,4th or 5th decimal place.
Forget things like Oscilloscopes, signal generators, Spectrum Analysers and other fancy test gear for now, they can come later when you know what they can be used for (AND how to use them).
The ability to make some basic sense of a circuit (schematic) diagram, otherwise you are on to a hiding to nothing.
This is where the likes of QRPLabs show their mettle, by not only providing very detailed construction  notes, but also detailed set up instructions with a lot of the hard work taken care of by being in the software
and accessed through the display.
Unfortunately, by making it relatively easy for Joe Bloggs to successfully build and get working, these kits, it will attract those with lesser skills to attempt something that MAY be beyond there current capabilities.
I would not dissuade anyone from having a go, but would advise to start on a few much simple projects, there are plenty of cheap soldering skill kits on Ebay that will get you going and get you skills (soldering especially) up to scratch
before you tackle something more adventurous.
Unfortunately groups like QRPLabs will by definition attract those who have had problems, and where would we be without such groups to help iron out such problems?
It is where the problems are caused, not because of the quality of the kits, but caused by the lack of skill/knowledge/understanding of the constructor.
Because it is the problems that get highlighted, that the casual observer can get the impression that these kits are not always up to scratch.
When, in fact it is the constructor that is not up to scratch.
I am not trying to put anyone off building their own gear, it is massively rewarding to operate something you have put together yourself, and would encourage anyone to have a go.
BUT, be prepared for disappointment, there are no guarantees in this game.
The BEST piece of advice I can give if you are starting out in the world of radio construction is to mate up with someone who has been doing it for a while and and can offer advice and possibly test gear you may not yet need/have.
Groups like this really are helpful but unfortunately remote, so is much harder to diagnose and get information across.
I am not trying to put anyone off, just offering some advice on being realistic when you tackle kits like these.
Just remember, there are times you just have to put things down to experience and move on to the next project.
You can always come back to the projects in the "to finish one day" bin. ( I have lots! LOL)


Re: A word of advice

Michael Greene
 

Mont,
My thoughts, exactly. I have learned so much and have never had so much fun and interesting experiences as I have building and using the QRP Labs kits!

Michael KN6IZE


Re: Need help with changing GPS Baudrate #gps

VE3KCL
 

I got that wrong  checksum 14 should be correct .... you may try other baud rates and checksums to see if any of them are accepted by the QLG.
If no changes are accepted then the MTK chipset in the QLG may not be suitable for your application.
Dave


Re: A word of advice

Mont Pierce KM6WT
 

Two additional(?) points I'd like to bring out (if they're already mentioned, sorry I must have missed them).

1) Anytime you order a 1.0 version of a product, one should be prepared and accept that you will likely see some issue(s) that have not fully been ironed out.  For some, this is part of the fun, for others, they should wait for the product to mature a little, at least version 1.1 And note: every revision (1.2, 1.3..) will have more of the initial issues ironed out.  So, if you are not prepared to accept a couple of initial wrinkles, be patient, and wait for a future revision.  You will be much happier.

2) The number of issues posted is not a valid measure of the quality of the kit.  Remember, builders with issues are many many many times more likely to create a post than the builders that had complete success.  This is only natural as those with issues pool together to help one another to solve issues.  While those with successful builds are busy on the air, making contacts, and having a blast !!  :) :)

Interestingly, point 2 above can be an indicator for point 1, and vice-versa.


I remember some time ago, seeing all the posts with issues on the QCX, and I did NOT order one.  It wasn't until sometime later I ventured in with an order for the QCX+.  A tried and true successful product, plus now with a well designed factory case, AND  a Development Board plug in which I really really admire !!!   :)  :)

One more point I'd like to make in regards to QRP-Labs' Kits: Their prices are so affordable, they are well worth their Educational Value Alone.  Just examine how many builders on this forum are learning new skills, venturing into SMT rework, expanding their knowledge of circuit designs, and more.  Not to mention the sense of comradery as they swap tips, stories, encouragement, tools recommendations, etc, etc, etc.

It seems like, QRP-Labs has produced more that just fun kits to build, but a culture of individuals that share Hans' enthusiasm for the Ham Radio Hobby.


73
km6wt