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QMX SMD assembly defect

 

Hi,
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I successfully built and revived QMX. It was a fun to build it and I really like the radio. Unfortunately, my PCB board came with an assembly defect. It had a solder bridge on the CPU at at least two pins and one of the pins seemed slightly bent. I guess it's VDD/VSS pins and maybe also tiny bridge to VCAP2. I microscoped the board before powering it up (as also recommended in the assembly guide), so I spotted and fixed the problem early (sorry for the low photo quality, I didn't have SD card handy, so I just photographed the scope display :)
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Fixed board:
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I think the QA process could be improved, such defects can be easily missed by builders.
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Nice catch! Nice job!
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73
Karl
KI4ZUQ
 

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I had bad soldering in 3.3 SMPS modul. There was a connection between the diode and the transistor.
 

Curious, had the same solder bridge on the chip also. Good job, wouldn't have a guess what would have made smoke if not corrected.
 

Finished my QMX+ today and is was not powering up.
The diode on the backside of the 3.3V module had one pad ripped away and was 90¡ã rotated.
As it looks to me, the pin is not bend enough to allow the 90¡ã rotation. Seems to me that this already happended during the soldering process. Luckily I had spare boards ordered with the kit, just in case...
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So, did you install the spare and is the unit OK?

GREG KI4NVX?



On Thu, Oct 3, 2024 at 11:13 AM, Dirk
<marvin@...> wrote:
Finished my QMX+ today and is was not powering up.
The diode on the backside of the 3.3V module had one pad ripped away and was 90¡ã rotated.
As it looks to me, the pin is not bend enough to allow the 90¡ã rotation. Seems to me that this already happended during the soldering process. Luckily I had spare boards ordered with the kit, just in case...
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Yes. Works fine with the spare, I'm already on-air with FT-8 :-)
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73
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Dirk? - DK7CVD
 

Excellent.
I'd personally not try to repair that SMPS for possible use except for rework practice and then run the standalone tests to see if I succeeded.

Greg


On Thu, Oct 3, 2024 at 11:25 AM, Dirk
<marvin@...> wrote:
Yes. Works fine with the spare, I'm already on-air with FT-8 :-)
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73
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Dirk? - DK7CVD

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