Thanks Rick.

I set the supply to 25mA wholly expecting it would immediately trip at the excess current demand of the QMX. BUT the power supply did not trip nor did the meters move off of the peg. So that indicates that no electrons are flowing from the 9VDC supply into the QMX.
--
73, Rick
VE7TK

Website:

?It counted up to a 100 , then I just got a blank screen and the QMX crashed

Taking my own advice I just swapped the CPU that had been involved in the problem back into the set.? ? ?After set-up It all works fine so probably only the 5351 was damaged.

I have used the EFuse products in MIL SATCOM power supply boards and they work great.? Depending upon the model they have under/overvoltage lockout, latching or retry on fault and inrush current control; many even have a fault bit output.
73, Don N2VGU

Well Charles, I thought I wrote a reply, but I can't find it. I did follow your instructions and found I can adjust the output audio. What I find, though, is I can adjust it to get a full bar graph, but then it dros to about 50% over a few seconds. What might that mean?

Wayne

Thanks all. I did look at the schematic when I found continuity all the way around and thought it was all connected, but I needed to make sure. I'm tracking back an issue with my QDX now and am just trying to eliminate potential problems.

Wayne

Hi,
if you measure it outside the board it is fault. If you measure it on-board there should be connection between oll three. Please, see the schematics.

73 Bojan S53DZ

Yes, normal. Look at the schematic. They are all connected.

-mike/w1mt

I do apologize for all of the questions I am asking today. I do have another, though. I ran a continuity check on each of the legs of the trifiliar transformer and they all test good. However, I get continuity between all of the legs. In other words, there is continuity all the way around the transformer. Is that normal?

Thanks,
Wayne

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Wayne,

I have a different radio set up with Windows 10, but I know that the OS sound settings can be very squirrelly.? Look for "Sound" app.? When you plug in your QDX you should be able to see the sound card appear and disappear when you plug in and unplug the QDX.? I would not use any external sound card since the QDX has a built-in sound card. To open the Sound app is slightly obscure.? Search "Control Panel" in the search box.? Go to "Hardware and Sound", then click on "Sound".? This should then have a list of sound devices on the computer. You should see the sound card appear in both "Playback" and "Recording".? The "Recording" side shows your receive audio and there is a bar graph on the right of the app that shows the level.? For my FDM-DUO, this level shows at about 50% to get a good level on WSJTX.? Transmit is shown under the "Playback" tab.? Under "Properties" in the lower right it opens a new pane that has "levels" if you need to adjust output.? When the radio is transmitting, you should see the bar graph under Playback and the appropriate device showing a level.?? I make my radio device "Default" for Playback and Recording, and I generally disable the other stuff, such as built-in mics and speakers, for testing purposes.? Windows is very finicky with sound configuration in my experience.?? Seeing the level on "Playback" doesn't necessarily mean the radio is putting anything out.? It just means Windows is creating a sound to send to the radio.? Personally, I would go to the Windows level setting mentioned above, and see if you can get the radio to come to life by slowly adjust the slider from nil upward.? There's no harm in leaving the radio in transmit if it's not putting anything out.

Computer audio systems were (in my humble opinion) easier to deal with on Windows XP or even Windows 3.11.? Since Windows 7, things have become much more obscure.? Not that other OS settings make it easy either.

73

Charles - NK8O

In order to make room for L508, D508 is installed with the body on the left side, with the stripe facing down, which is different than any of the other diodes.

There is a blurb in the text that discusses D508 and D511, but it doesn't mention this--you sort of have to infer it from the photograph of the board.

Hope that helps,
Jonathan KN6LFB

I had a similar (maybe lightning) problem with a QCX+5W.? ?In that case I replaced the Si 5351 A-B-G? several times as well as the QCX demodulator chip (you don't have)? without getting it going.? ?

I wondered if the first 2 5351A B GT 's? were miss sold pre-programmed ones so tried one from another source.? I used my spare CPU chip too the third time of praying and it all worked again.? I've not swapped the CPU back yet but suppose I ought to get round to it.??

?

The chip that definitely did work was?

On 24/08/2023 17:41, Wayne Greene wrote:

I ran RF filter sweeps on all of the bands to see if maybe something was wrong with my LPFs (assuming that's what this tests).

Wayne.

It tests the BPFs. Unless your LPFs are very bad they will make no noticeable difference.

73 Alan G4ZFQ

Looking at the photo on page 24 of QMX manual h, I think maybe diode D508 may be pictured in the wrong orientation.

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My main ham system is a Pi-400. Works great and no funny issues like Windows.

Thanks. I'm sure there is one, as well. I'd say this is causing me to pull my hair out, but I'm already bald...HIHI. I may try running this on a pi to see if I get better results.

Wayne

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I've been following the thread on your audio issue. Very strange as obviously the sound card is working and Windows sees it. I'm not a Windows guy, just have a test setup with Win10. Anyway I'm waiting to see what the solution is. I'm sure there is one.