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Well, I bit the bullet and installed the 003 FW. Update of FW went all fine, no issue there. I wired up a electret mic I found in my junk box. Tested the mic on pc and sounded fine. I made an adapter using the electret mic and a foot switch for ptt. The Mic and ppt switch works. But... Testing SSB TX with QMX on dummy load and listening on my ICOM 7300, the audio is badly distorted before calibration and even worse post calibration. So much so that the speech is unintelligible. The audio sounds like the QMX is only picking up the peak signals from my voice. Most of the calibration plots look nothing like the example ones from the release notes. And only a few mildly resemble the examples. Adjusting mic gain to about 70 seems to improve the audio. However, every time I key up, there is now an awful lot of noise before I even start speaking. Once I start speaking the audio is ok'ish with a load of background noise. I tried messing about with other SSB settings with no improvements. I did find a second electret mic that gave me similar results. I have now set it back to factory default and seeking advice. Any suggestions? Mel. M0KMD.

Hey all! Got my QMX+ rev 3 last week and have had a blast assembling it over the past few days. Finished it last night, booted just fine, and was able to tune some CW on 10m with a big grin on my face ? The thing of it is - after a few minutes, it froze. The LCD contrast went a bit darker, audio output stopped, and all front panel controls had no effect. Unable to power off by holding the VOL encoder, I had to cut power at the source. A short time later I was able to boot back up, browse some bands, tune some CW, and then it freezes again. Same symptoms: LCD goes higher contrast, audio stops, all controls stop, have to cut power. I'm pretty new to debugging PCBs but figured I'd dive in as best I could to gather some info, and here's what I've been able to piece together: I wired it for 12V, and based on measurements my battery was delivering consistent 12.13V Contemporaneous with each instance of the board freezing was a drop from 12.13V down to 12.0V I checked a number of the components around the PWR_ON and PWR_HOLD circuits, and no blown components However, the measured voltage across R105 went from ~3V (normal operation) to ~4V (frozen) No smells or popping sounds like components faulting/failing No changes to the LCD indicating on-board protections or anything like that Tried running 9V in case there were unobserved fluctuations in my power source, but it was the same behavior - a few minutes of normal operation, and then freezing measured voltage during operation was around 7-8V I've tried connecting to the serial terminal to check the on-board diagnostics, and that seems to be the most consistent way to trigger a freeze. Without trying to connect a terminal, I can usually get about 2-5 minutes of normal operation between power cycles, but as soon as I attempt to connect the terminal, it freezes. Like I said, I'm new to a lot of this but eager to learn so forgive me if there's obvious debugging steps I've missed ? ??. But yeah, not quite sure where to go from here! Would greatly appreciate any help or pointers!

Hello, I recently just fished putting my QMX Rev 4 kit together with the windings necessary for 12v input. As I was going along I verified I all continuity checks as instructed and verified no pads were bridged. Upon attempting to power on the device, I connected my 12v power supply to the barrel connector. The screen immediately lit up and I had black rectangles across the top half of the screen. A second or two later I started seeing smoke, heard a pop, and the screen went dark. Upon further inspection, I was able to discern that the Q108 MOSFET on Plug-in PCB #1 blistered and exploded. The L101 inductor nearby also looks a little singed but the enamel coating does not appear to be compromised. I do not see any other areas of the device that appear to have been compromised or damaged. I was wondering if anyone may be able to assist with what actually went wrong here. I have ordered a new power supply board as well as a replacement MOSFET to try my hand and replacing the bad component. My current theories on what went wrong are: I am missing a bad solder joint somewhere that caused the issue, still attempting to find one if so. It's still unclear why the MOSFET would blow in this case as it's rated for 20V and my power supply used is only capable of 12V out. MOSFET AO0415A Data Sheet There is a step in the instructions that says to bend a tab of the LCD screen at about 45 degrees to clear the L101 inductor. I noticed that this appears to have been discolored possibly due to heat. There's a good chance that this tab was not bent quite enough and made contact with the top face of the L101 inductor, though I don't think the top face is conductive. This could have resulted in a short to ground? My winding on the RWTST Transformer is somehow incorrect. Image upon powering up. Seconds before smoke and pop. Note: I did not press the left dial in, the screen lit up as soon as power was supplied to the barrel connector.

Hello, I bought a QDX used and never got around to using it. What is the best way to tell what voltage it requires and if it is high or low band? I believe it is 12v and low band, but not 100% sure. It power on ok with different voltages, and wsjtx allows me to select any band. I didn't want to try txing since I might be using the wrong voltage. Thanks!