Where are these on Sale?

Hi Steve,
Forgive me for making absolutely no assumptions - I mean no offense, I just want to know how to respond:
Here are four fundamental questions that I would ask you and all people asking for help to answer on their first post. Answer to these questions are extremely helpful in defining the possible scope of our diagnostic efforts...

1. Is this a factory build or a kit build?
2. What test equipment do you have available to you ? Do you have a DVM? An oscilloscope? A dummy load?
3. Can you read electronic circuit diagrams and identify components?
4. Do you have sufficient technical skills to accurately diagnose and replace components on the unit with support form this group?
 
This unit works on a single power supply, and the receiver is predominantly a DC-coupled chain of operational amplifiers. This means that a lot of information can be gained by simply measuring DC voltages along the signal path. If either of the output pins (pins 1 and 7) of any of the operational amplifiers (IC5 to IC10) are at zero volts or at or above half your supply voltage, then you have a clear indication of the proximity of the fault.

My first guess for the problem would be a leaky capacitor along the audio chain, so the voltage measurements suggested above would get us a quick read on unit health.
--
Julian, N4JO.

5 sold in the last 24 hours lol

Mike (WA4MP), thanks for posting the link to the QRPometer kits for sale! Just clicked through and bought mine. :)

I'll add my voice to this. I have built two QCX originals, and two minis. Both of my originals worked perfectly the first time. The first mini had an issue with a capacitor that I may have caused by misreading the instructions and it took me several weeks to sort out, but was a success with the help of this group. The second one was a damaged one sent to me from another ham to repair, and I repaired it with Hans' help. I've made contacts with all of them. I got my 1000 miles per watt award with the first one. These kits are relatively low component count kits, and Hans has provided good trouble shooting videos, so most issues can be solved quickly with due diligence, a good soldering iron, and a multimeter. 
--
73, Dan - W2DLC

Great question!  I've wondered the same thing.

I've built 2 QCX Classics.  Both worked right away.
I've built 2 QCX Minis - Both worked right away.
I've also had the same results from my multi-band Ultimate 3S.
Hans is the new Mr. Heathkit to me even if he doesn't design projects with tubes and big power transformers.  (SMILE)
IMHO, his assembly instructions are second-to-none.
I think most of us would agree that Hans has brought new joy to our hobby/passion with his products as we wait eagerly at the computer screen awaiting his next release.  
Thank you, Hans.

https://www.youtube.com/watch?v=jFAB2a31yrA&t=130s

This is the result of my QCX-Mini build for the 15 meter band (5W at 11V) using a wire dipole antenna, having 100% of SOTA confirmations done.
https://www.sotadata.org.uk/en/log/activator/show/580000

73 de PY1ZB
Roney

Chris
Try going into WSJT setup and changing the playback source to another source then changing it back.  That has worked for me and may provide a clue.

I was "lucky" and captured two log files from subsequent sessions, one successful and the other not.

The attached file "Sucess" was first: Powered the QDX up, entered terminal (PUTTY), cleared log, set log to "ALL", exited terminal, started WSJT-X, closed WSJT-X, entered terminal
Just two minutes later, I restarted the QDX by unplugging power and than followed the same procedure as above. This time the WSJT-X showed the failure. The respective log file is "No success".

Note: Both sessions were done with "Kenwood TS-440S". Very first tests with "Kenwood TS-480" showed no difference, but will try more.
All other setup details, see my earlier post in this thread. 

73 Chris OE1CGS

On Tue, Nov 23, 2021, at 05:28 AM, Curt M. (WU3U) wrote:

The thing about Hans kits is that the success rate is solely based upon the skills of the builder. By the time the board itself hits the street there are at least no major errors on it. Yes there have been some component changes and minor mods from time to time but no bad circuit boards. As long as you take your time and do everything carefully (including checking the integrity of the components shipped with the kit) you will have a successful build. 

Curt,

Just a minor correction.  In the first release of the QCX-Mini, there were reports of damaged surface mount components from the original SMD board supplier to Hans.  This was one of the first kits that had a significant amount of surface-mounted devices (SMD), at least as far as I know.  Hans took care of it right away and now does a 100% inspection of all boards coming in with a test jig that he designed and built.

I would like to add that the QRP-Labs instructions are by far the best that I have seen.  This greatly improves the success rate for builders.  For our club of builders, I do not know of a kit that we have not been able to make work.  The success of first power on I do not know other than personal experience and that is 100%.  My current issues with the last kit I built (a QDX) are related to a new device and Hans is working on the root causes.  Still, it worked out of the box it was later failures that brought out the issues.

73
Evan
AC9TU

Hi Evan, thanks for your comments.

I wrote my message a few days ago and I suppose it took time to get approved because it was my first post.

Since then I have tried every combination on startup of antenna on or off, the way the power is connected and battery versus power supply. The only thing that seems to work with my QDX is to rapidly cycle the power using the switch on the power supply and even that doesn't work all the time.

For the startup frequency I have done the factory reset quite a few times which always results in a startup frequency of 0.707405 as I mentioned. I did figure out how to edit the startup frequency in the configuration - only PuTTY works properly, minicom and screen don't. I think it is probably the way that the backspace character is handled by the QDX that is the issue but I haven't explored it further. In any case when I use PuTTY and edit the frequency it still is wrong on startup.

In answer to your question about which radio, I am using the TS440S setting and CAT seems to work perfectly.

For now I have put the QDX aside without torturing it anymore as I'm thinking there will be a firmware change coming soon :-)

Rick

The thing about Hans kits is that the success rate is solely based upon the skills of the builder. By the time the board itself hits the street there are at least no major errors on it. Yes there have been some component changes and minor mods from time to time but no bad circuit boards. As long as you take your time and do everything carefully (including checking the integrity of the components shipped with the kit) you will have a successful build. 

Curt

It may not be related, but since I grounded my case I have not had any unexplained 'suddenly stops working' issues.

Hi,

Evan, in WSJT-X v2.4.0 there is no "Kenwood TS-440" available, I am using "Kenwood TS-440S". I will check into the "Kenwood TS-480" as suggested by you.

Alan, the period covered by the log is several days and a couple of sessions. No wonder, some errors are shown on several occasions. I cleared the log this morning and will set to "ALL" for the next session(s).

73 Chris OE1CGS

Rick,

One other question I forgot to ask was which radio do you have selected in the WSJT-X settings?

Evan

Hi Chris,

In addition to Alan's suggestion and question, I would add the radio that you have selected in the WSJT-X settings file.  I noted that the QDX reports a Kenwood TS-480 but the manual says to use the 440 first.  Have you tried the alternate radio?

73
Evan
AC9TU

On Tue, Nov 23, 2021, at 01:29 AM, Rick MacDonald / VA1UAV wrote:

Everything is working fine with mine except I have the same startup noise issue that Evan and Gregg have described. In my case turning the power off and then back on quickly seems to consistently fix the problem.

Here is the result of the audio filter sweep when the startup noise problem occurs:

Another issue is that the QDX never initializes to the default frequency of 7.074000 it is always 0.707405 even when it starts up without the noise problem. If I try to edit the startup frequency in the configuration utility I can only seem to add a number to the end of the string. For example 7074000 becomes 70740008 when hitting the 8 key and then that can't be changed or deleted. After that the frequency is 70.74008 on startup. Very strange.

I've been using a Raspberry Pi 4 running Buster and QDX firmware 1.01c and my QDX was built for 9V operation. To communicate with the terminal applications I'm using minicom. I've also tried the QDX with a Mac running MacOS Catalina and get exactly the same startup issues.

For power I'm using a current limited switching supply but I've also tried using a 8.4V LIPO battery with no difference in behavior.

Hi Rick,

For the startup audio issue have you tried starting with the antenna disconnected from the QDX?  That seems to help me at times.

For boot-up frequency, did you try doing a reset to factory defaults?   The other thing that I noticed is pressing the left or right arrow keys while the cursor is on the startup frequency then pressing the backspace key deletes the frequency. 

For my setup, I run a Raspberry Pi 4 or a Windows10 laptop.  Both on WSJT-X 2.5.2

Most of the time My QDX Info:

1. What PC software you are using: Windows10 Home with all updates using WSJT-X 2.5.2
2. QDX firmware version you are running: 1_01c
3. Whether you built the QDX for 12V operation (output transformer 3:2) or for 9V operation (output transformer 3:3).  Built for 12 volts
4. What power supply you are using: voltage, current capability, and whether it is a Linear or Switched Mode type.  12.2 volt Battery
5. Now everyone has Rev 1 PCBs, but in the future when Rev 2 comes along, please also state what PCB revision you have.  Rev 1
6. Also, state any deviations you intentionally made from the manual. We may need to know about your deviations  :-/  The only deviation was to remove the SMD inductors before starting the rest of the build.

73
Evan
AC9TU

There are two indications that something is wrong and they *always* come together: A *red signal strenght* indicator (79 dB) and an indicated *frequency of 0,707405*.
Both occur right when starting up WSJT-X. But not always. I'd roughly

For what it is worth I attach my log file. It was aquired with the "Errors only" setting.

Chris,

Hans is looking into this problem, hopefully he will come up with an answer.

I do not know if the log will help but I suggest you log ALL for a short period until a fault occurs. Then save it. Clear for the next check.
Your log shows a lot of errors but what period does it cover? From where did the unknown commands come? One fault or many faults?

73 Alan G4ZFQ