Basically, you are bottoming out the long male pins into the installed female socket. Hans shows a picture of the long male pins bottomed out in an uninstalled female socket, and mentions this on Step#1 of page 50. Your socket will have already been installed. Then the plastic former gets pushed down until it contacts the top of the female socket. The point of this is two-fold: to get an exact fit of those male pins into the female socket, no more and no less, and to properly position the former to act as one-half of the spacer underneath the control board. The little green PCB is the second half of the overall spacer underneath the control board. Everything is fit together in place, and soldered. Yes there is an excess length of pins that need to be trimmed. Step 3 and Step 4 show this. Everything seems clear to me, and made sense as I was assembling. I am not sure what you missed, other than maybe the "why" the pins are fit, spaced, soldered, and trimmed in this manner.

On Sat, Aug 19, 2023 at 03:23 PM, Mike wrote:

when set at
exactly 10Mhz the frequency was a few hz off. Probably something to do with
the SI5351 maths

This got me thinking.? Does the VFO/Signal Generator display...?
1) The frequency requested by the user
2) The actual frequency selected by the VFO/Signal generator internal algorithm and based on the SI5351 maths
The latter would be more useful as long as the user realised why it wasn't exactly what was requested
If it is the former, could this be a firmware update, either fixed or as an option?

Nic, to clarify, I imagine that when you're testing for continuity between Bl and Br, you are shifting the probes around until you hear the continuity buzzer. At this point, you have mutual contact with exposed portions of the copper wire. The wire is continuous, unbroken, so you have achieved continuity that is not dependent upon good electrical connection to the circuit board pads. The electricity is flowing through the wire, and not the board traces. The solder blob of Bl probably has electrical connection with the pad, but not the wire. The solder blob on Br may or may not have electrical connection with the pad and it may or may not have electrical connection with the wire. In any event, you are able to shift the probes around and either manage to test the path from the Bl pad through Ar, Al, and then pin 7. You have also been able to shift the probes around to test the ends of the B wire. Your goal is get the connection solid enough between wire ends and pads, that you can touch the probe tip anywhere on the Br solder blob, and get easy continuity with pin 7. Then you at least know you have a good connection with everything in between that solder blob and pin 7. I don't know that you need to desolder the wire B pins, because they use the thinner wire with the far easier to burn off enamel. Just try to reflow the joint, after 10 seconds or so, circle the iron tip around the circumference of the wire and maybe give it another 5 to 10 seconds whilst doing so. Just be mindful of nearby components. If you have extra flux, add a generous amount around the joint, before doing this. That will help prevent solder bridging and keep the solder where it belongs. If no extra flux, just be careful. I was too lazy to grab my tacky flux, so when reflowing joints, I just added extra solder, relying on its flux. That meant more solder bridges and more work for me. I had the tacky flux and should have used it, but in the end I got it done, albeit with more work. Important, be sure to reflow both Bl and Br. At this point, where things stand, you have no guarantees that you have good solid connections between bare wire, solder blob, and pad, on either of those joints.? ? Sorry for the long-winded captain obvious book.

Hi,

I've been using the QDX transceiver for a while, mostly in portable operations,, and very satisfied with it's performance.

In one of the usages a bad connection of the antenna ended with no power output since it, naturally I thought immediately on finals being blown up, I replace all 4 transistors.

After that the power yield is extremely low, unusably low, and I suspect the problem might be with the failure afecting the driver stage as well.

But when testing I noticed the driver signal is ok (see figure QDX_PA_Gate.png).

With a dummy load and enabling the tone transmission of WSJT-X I measured the tension at the drain of the finals and to my surprise the signals were there and they were remarkably not similar. You can see the signals on Q1,Q2,Q3,Q4 (not in the schematic but looking counterclockwise at the board from the USB and balum side). The tension seems to be similar by pairs.

Any suggestion of fixing strategy based on experience with similar behaviours you might want to share?

73 de Pedro, LU7DZ

During assembly I struggled with page 50 of the manual which has conflicting photos and instructions that
appear to be not valid. I found the male pin plug pins were too long and needed to be trimmed by about 3 mm or so.
Also the board shown? appears to be an older REV. How did other successful builders navigate this page?. Am I missing something?

Paul DJ0CU G4ADF

Hi Joan,
In Germany I use a "ESD-Matte" and "ESD-Pinzetten" by Pollin Elektronik (Germany). I don't know the english word for it. You can search by Google by using this both words. So I think, that the building up the QMX-Kit is much better than the building the QDX-Kit without the ESD-Matte and ESD-Pinzetten. ?.
Vy 73 de Dc4kjs?

On Sun, Aug 20, 2023 at 09:36 AM, Nic Heath wrote:

It's just blowing my mind I can see continuity between Bl and Br but the other tests fail.

Are you checking continuity between the cut ends of the wires or (correctly) between the PCB pads?? You can also probe between wire and its pad to further isolate an open joint.??
I haven't found anything better than ordinary sewing needles for this task; use the "sharps" kind not blunt embroidery needles.
73, Don N2VGU

If your probes make good contact with conductive regions of the Bl and Br wire ends, you will see continuity. One of those ends does not have a good electrical connection to the board.

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Frank, the Mouser website is in error with the 350mW power dissipation rating on the BS170-D75Z part. 300mW PD applies to the MMBF170, which is the SOT-23 packaging. The BS170-D75Z is TO-92 packaging, with spread legs. It has the same 830mW PD as the plain BS170, which is also TO-92 packaging. The plain BS170 differs in that the legs are straight, with 1.27mm (0.05") spacing. TheBS170-D75Z's spread legs have 2.54mm (0.10") spacing, which I believe will fit the board even better, because straight legs would need to be spread apart. Don't worry about Mouser's error, other than maybe report it with the "See an Error?" link near the top of the page.

Hi there,

I was about to start building a QDX low band kit, but I saw that I needed to take EDS measures and I was a bit put off. What precautions am I suppose to take or situations to avoid?
Thanks for your comments!
73
Joan

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Ah, OK, then maybe you have a USB-c charge-only cable? ?Since everyone’s standardizing on USB-c for charging things, and they don’t care about data(*) there are a lot of charge-only cables out there.

Hello Willie

Thanks for the gen.

I am not using a C to C, it is a C to A.

Albeit, I tried the pair of 5.1k'as anyhow.

But made no difference.

Cheers

Ian G4GIR

There are some issues with USB-c to USB-c cables if your computer also has USB-c, which can be solved bby adding some 5.1K resistors to the QMX, or by using USB-A on one end (and if nessesary converting that to USB-c with an adapter, as Mitch discovered).

73, Willie N1JBJ

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