So after a month using my QMX with great success. However, it's now broken ;-( ... likely due to this current discussion. It was powered up, not transmitting, and the power cord going to a 12V trigger USB-C device got bumped when I turned my PC a bit. So I suspect it took a 5v to 12v power hit.

I've not opened it up yet, but the QMX powers up, menu works, hardware diagnostics on the terminal all look good including showing power from the 3.5v and 5V supplies in the hardware diagnostics as expected. But I just get static noise on the audio output, and all the RF filters sweeps which used to look great, are all garbage. Paddle input does not work in Practice Mode like it used to.

Would these symptoms point to that D108 Zener, or do I have something else gone wrong?

I'll be digging into it later this week to see what I can see.

Thanks!

Loved this little QMX while it worked, so am anxious to get her back on the air!

73 de Roy - KI0ER