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Hi Jim, all I'm glad to hear that all is well and it is working but I don't really understand what is UNEXPECTED about the way the PTT output is implemented. It's clear on the schematic that what is

Hi all, here are my test results and the pleasant final results from the working QMX (20 m - 10 m). I've made some steps. 1. Checking the uncertainty of measured values for L I have a set of filter

Bojan, Roy, and Chris - thanks for the replies and tips on how to test that the PTT is in fact working. And surely enough, IT IS!! I metered between Tip and Ring and also between Ring and shield -

Thanks Hans for the quick answer. No problem, the frequency is really accurate. I was fiddling with the QLG2 and found nothing for calibration. But it's not important. 73, Ludwig

Evan, I think your analysis is spot-on correct. The TX pin of the MCU is directly in the line of fire for an overvoltage fault starting at the BS170s. JZ

James and John, I have seen this on a damaged Rev 1 QDX that I bought from a Ham that did not want to try to repair it.? At first, the QDX would power up and connect to the PC using PuTTy.? After

I can confirm this observation.?However, this does not seem to apply to the interference that occurs when nearby stations are transmitting at the same time. 73! Simon

Have a look at the output of the supply as you plug and un-plug it. DC couple and trigger off of the output and you are looking for spikes and excursions during turn on and off. Repeat by connecting

I ran into the same problem with a MIL SATCOM terminal I was working on.? Since blue-yellow is 1/10th or less common than red-green, which I also have, we ended up using blue-yellow LEDs and

James, That is a sad and surprising result. At least you have an answer now. JZ

Thank you for your help. I removed the TCXO and L15 and still found 7 ohms to ground on 3v3. I never actually thought to put my finger on the MCU as I didn't consider that as a possibility, but

Removing L15 will disconnect the clock generator from 3v3. That might be a good test. I hope it is not the MCU. I have never seen a QDX MCU fail. JZ

Thanks, John. I did just remove IC1 and here are my results: IC1 output pad to ground = 6 ohms. IC1 isolated gives normal 3.3v output and minimal current draw. Board current with IC1 removed =

James, one more thing... The event that took out your BS170 may have reached all the way back into the clock generator chip. If you find that the fault is on the 3v3 rail, there is a good chance that

James, ouch!, that sounds pretty grim! Recall that the 3v3 regulator runs off of the 5v0 rail so in a sense everything runs off of 5 volts and the short could be anywhere. Removing IC1 may help the

I'd like to add a little more info from the troubleshooting I've just completed. IC5 is still removed. With IC2 removed, current draw = 0ma. -- I trust this means that my issue lies with something on

In my clock kit manual, Hans says to use a clean well regulated power source. I grabbed a 5v switcher from the collection and since it was running 5v with or without the load I went with it. Sense I

I have a project at work where I needed to simply convey a bunch of machine states. I was amazed at how much information I can share with a 3 color LED. With color and solid and blink I can easily do

As you say it is a BIG change. Requiring new PCB to take the extra components and processor connections. Maybe a LED to show it has activated. The QMX is slowly progressing, then the QSX... 73 Alan

Kjell, I would try using a lower voltage, maybe a QCX would work as low as 7.5 volts. Separating the PA power feed would enable lower voltage, lower power out. 73 Alan G4ZFQ