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Check the screw that holds the BS170s, there is a 5 volt track under it.
Philip g7jur

Dear Philip,

thank you. I removed the screw. No change. Still a short. Annoying. I am now abroad for a week.

73, Holger DL9HDA.

Check for a short between the left encoder body and the back of the power socket. It's a very tight clearance. I had to move my power jack out as far as I could and also filed the encoder body for good measure.

Hello, I understand the problem. But in my case, the short circuit is present even though all four plug-in boards are removed.

73, Holger DL9HDA

I had the same problem. Tracked it down to the MCU by eventually lifting each VCC pin on that chip (very carefully-I had to fashion a tool and use the big microscope) until the short cleared. Measuring back into the chip I confirmed that it was definitely shorted. Check the VDD protection? zener (D109) for proper operation.
The only recourse is a new kit if your problem turns out to be to be the MCU.
GL,
Don

I need to clarify and apologize. Like many others, I often refer to VDD and VCC incorrectly even though I know the difference. I meant "VDD" pins on the MCU. There aren't any "VCC" pins (5 volts) there.
All the VDD pins except for VDDA (pin 22) had low resistance shorts to VSS.
My VCC supply bus (5 volts) was not affected.
Just to be clear. Sorry about that!
72, Don

Hi Ryuji,
My D109 was just "soft", having a high internal series resistance. It still began conducting at the proper voltage, it simply didn't conduct much current and allowed more than 5 volts to be applied while conducting less than 100 ma. I suspect that it was bad to begin with and not a result of failure in the circuit. It didn't over-heat. It just let the MCU get over-voltaged.
We'll never know for sure. A shorted zener would have been nice!
=Don=

Hi, D109 is on ps #2. It is not plugged in.

73, Holger DL9HDA

Hi, VDD has a short. Not VCC.

A new kit is on the way. Before any soldering I will check.

73, Holger DL9HDA

Holger, read this topic and later you will have the opportunity to replace the MCU.
--
Gyula HA3HZ

Hi Gyula, I'm following. It would be great to get a replacement.?

73, Holger DL9HDA

Hello,
My QMX also does not start.? When assembled, pressing S1 draws a high current and the external power supply immediately goes into current control.? I followed the suggestion and disconnected all boards (2x PS, 1x LCD and 1x Controls).? I also removed the screw holding down the transmit transistors.

With the boards and the screw removed, I measure about 12 ohms from VDD to ground.?

Could someone tell me what resistance is measured on a healthy board??

Thanks, Marshall? AE2J

I have 2? QMX's with a shorted MCU.?? Han's may have luck and sell us an programmed MCU soon.
But I have to verify there are absolutely no shorts on everything else prior to installing the new MCU.
One of my MCU's mostly works but no sound comes out of it or is detected when viewing on WSJT software.
So if I can get a new programmed MCU I will try it one last time, to save a radio.