Date   

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:

I have lowered the price of my Beginning C for Microcontrollers book on Amazon (search: B08GFDGN7P). Also, the small font size issue has been corrected and the book no longer tosses in a few blank pages for no reason. (The narrative was always all there; it just inserted blank pages.)

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


Help needed diagnosing newbuild QCX+

Leo
 

Visible symptom: line of black characters at top of display. 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. Coils are good. Checked all ground solder joints with respect to JP6 ground (and others where convenient.
Voltages (where they differ significantly from expected I have coloured them red):

+ve supply terminal: 11.26 (11.98) (my battery needs charging)
Clk0: 0.9 (~1.7)
Clk1: 0.9 (~1.7)
lhs C2: 3.40 (3.40)
rhs D2: 4.94 (4.96)
T1 pins 1,2,3 & 4: 0 (0)
T1 pins 5,6,7 & 8: 2.47 (2.36)
C43: 2.47 (2.28)
C44: 2.47 (2.44)
C45 1.3 (2.42)
C46: 0.87 (2.30)

IC5 pin 1: 2.47 (2.64)
IC5 pin 2: 2.47 (2.46)
IC5 pin 3: 2.47 (2.26)
IC5 pin 4: 0 (0)
IC5 pin 5: 0.89 (2.28)
IC5 pin 6: 1.33 (2.46)
IC5 pin 7: 1.38 (2.44)
IC5 pin 8: 11.23 (11.67)

I haven't recorded the voltages for the subsequent opamps as the discrepancies carry through.

It seems that the output of the FST3253 is throwing the voltages out in the receiver section.

IC2 appears to be non-functional and this may be why the SI351A is not outputting the correct Clk on 0 & 1.

I measured the voltages on each of the IC2 pins without and with the chip in place and they would seem to indicate something is going on, but it is not communicating with the display.:
pin 1:   0        4.6
pin 2:   4.93   4.92
pin 3:   4.93   4.92 
pin 4:   4.93   4.92
pin 5:   4.93   4.92
pin 6:   0        0
pin 7:   4.94   4.93
pin 8:   0        0
pin 9:   0        2.42
pin 10: 0        2.45
pin 11: 1.08   1.08 
pin 12: 0        0
pin 13: 0        0
pin 14: 4.94   4.94
pin 15: 1.93   1.93
pin 16: 0.01   0.02
pin 17: 0        0
pin 18: 0        0
pin 19: 0        0
pin 20: 0        4.15
pin 21: 0.1     0.01
pin 22: 0        0
pin 23: 2.45   2.45
pin 24: 1.93   1.93
pin 25: 0        0
pin 26: 0        0
pin 27: 3.47   3.47
pin 28: 3.40   3.40

The display voltages are:

LCD pin 1:   0      (0)
LCD pin 2:   4.93 (4.94)
LCD pin 3:   0.87 (0.57)
LCD pin 4:   3.48 (4.92)
LCD pin 5:   0      (0)
LCD pin 6:   0.04 (0)
LCD pin 7:   4.92 (1.08)
LCD pin 8:   4.92 (1.08) 
LCD pin 9:   4.92 (1.06) 
LCD pin 10: 4.92 (1.04) 
LCD pin 11: 4.92 (0.00) 
LCD pin 12: 4.92 (4.94) 
LCD pin 13: 4.92 (4.92) 
LCD pin 14: 4.92 (0.00) 
LCD pin 15: 4.92 (4.41) 
LCD pin 16: 0      (0) 

There's a conclusion to be reached here but it is eluding me.
I'm about to embark on another component by component check of value, orientation and solder joint. It's probably worth saying that I measured every single resistor before I placed it.
I haven't had the scope out yet as there are clearly at least a couple of fundamental issues to chase.

Hopefully this will all ring a bell with somebody and it will boil down to a bad joint or misplaced component or another face-palm moment. That's okay - I'm a programmer so debugging has taught me that no matter how many times you look at something, you still miss the obvious. 

Help would be much appreciated.


Re: Need help with changing GPS Baudrate #gps

Frank - DB1FW
 

Well -   Checksum 30 would be valid for "$PMTK251,4800"
But the $ is not included in checksum calculation. 
So "$$PMTK251,4800" would result in checksum 30 
and "$PMTK251,4800" would result in checksum 14

But I'll just try it with checksum 30 as well....
--
Frank - DB1FW


Re: Need help with changing GPS Baudrate #gps

VE3KCL
 

The nema checksum may not have have been correct

https://nmeachecksum.eqth.net/

Dave


Re: Need help with changing GPS Baudrate #gps

VE3KCL
 

Hi Frank  try $PMTK251,4800*30


Re: Need help with changing GPS Baudrate #gps

Frank - DB1FW
 

Hi Dave,
thank you for your reply. 

Well - the QLG1 GPS Receiver comes with a backup battery so it should keep the settings. 
But, the problem is - it does not accept baud rate change. 

As far as I found out, the reply from the GPS "$PMTK001,251,2*37" is something like - "Valid command / packet, but action failed"

--
Frank - DB1FW


Re: A word of advice

Dave VE3GSO
 

I have to agree with everything said here.

The QRP-Labs kits are second to none.  Hans has even included excellent explanations of how the kits work, in the case of the QCX going through each stage, while also giving credit to where the circuit original design comes from.

The only time I have had a problem with one of these kits is when I assumed I knew what I was doing!  Of course Read the Manual set me straight!

I think the following tools essential:
Temperature regulated soldering iron with a fine chisel tip.  The cheap irons get too hot and burn out their tinning far too quickly.
Tweezers for picking up small parts.
Small needle nose pliers for bending leads. I tend to use my finger nail and finger pressure.
Small slot and Philips screwdrivers.
Flush wire cutters.
Solder wick, liquid flux, 63/37 flux core solder, Q-tips, Isopropyl alcohol for cleanup.
Illuminated magnifying glass to actually see what you are doing in good light.  I have used drugstore +2.5 reading glasses and a desk lamp, but modern LED magnifiers are pretty cheap online.

Practice on an old board.  Anybody interested in electronics must have old floppy drives, a dead printer, a motherboard, etc to practice on.

And of course, when help is truly needed, this list is here.

Dave

On Jan 23, 2021, at 09:23, N3MNT <bob@...> wrote:

Although experience may help in some of the issues we are seeing, I think that many of the issues people are having are caused by not carefully following the instructions.  Hans has done an excellent job of creating easy to follow assembly instructions including identifying potential pitfalls for specific steps.  Reading through the posts by those having issues, it is surprising how many are the result of missing parts, poor soldering, incorrectly placed parts etc.  There are many posts where the  builder says they have checked the solder connections several times and they are all good, only to see the resolution was to reheat one solder connection. 


Re: Need help with changing GPS Baudrate #gps

VE3KCL
 

Hi Frank

It is possible with a rom based gps, that the baud rate change does not survive a power recycle, and the baud rate change string has to be sent each time you want to use that new baud rate.... which would not be very convenient.
Dave VE3KCL


Re: Puff of smoke, what now?

N3MNT
 

Digi Key or Mouser.


Re: A word of advice

N3MNT
 

Although experience may help in some of the issues we are seeing, I think that many of the issues people are having are caused by not carefully following the instructions.  Hans has done an excellent job of creating easy to follow assembly instructions including identifying potential pitfalls for specific steps.  Reading through the posts by those having issues, it is surprising how many are the result of missing parts, poor soldering, incorrectly placed parts etc.  There are many posts where the  builder says they have checked the solder connections several times and they are all good, only to see the resolution was to reheat one solder connection. 


Re: No transmit

Roy WN3F
 

I got them from Mouser, my favorite source for parts.  They ship very quickly!