QRP Labs QCX-mini

QRP-Labs QCX-mini

Assembled QRP-Labs QCX-mini with dummy load and replacement op-amps.

The QCX-mini is a continuous wave (CW), think Morse Code, ham radio kit that transmits and receives on one band only at around 5 watts. I had been waiting for the release of the QCX-mini kits for a while and was able to order one as soon as it was released. I also bought the aluminum case and the 50-ohm dummy load.

The kit was pretty straight-forward to assemble, I am very proud of my soldering on this kit, it is the best I have ever done, but…

When I was done and went through the alignment process it didn’t work. I went off to the QCX forums to see what I could do. Turns out there is an issue with the pre-installed surface mount op-amps used in some of the early kits. The solution is to check the voltages of each op-amp, there are quite a few of them, and then replace the ones that aren’t working as designed. Also using an oscilloscope is recommended to collect more troubleshooting information.

I bought a 10 pack of op-amps directly from China on eBay, they arrived a lot faster than I expected.

I bought an inexpensive scope for Ali Express, the DSO FNIRSI-150 Digital Oscilloscope full assembled with P6020 BNC standard probe, along with an extra probe. I’ve turned it on but haven’t learned how to use it yet. I am hesitant to use the scope as some members of the forums have shorted out their radios breaking a lot of components in the process, the surface mount components are so small I can see myself doing that.

This also led me to buy a hot air rework station. After a lot of research I bought the Sparkfun Hot-Air Rework Station – 303D. I chose this unit because I trust Sparkfun and they stock replacement heating elements for it.

But I have never soldered surface mount components or used a hot-air rework station so I bought a handful of SMD kits to practice on, there will be blog posts in the future about those.

As of right now I have a non-working QCX-mini which I am pretty bummed about. QRP-Labs is in the process of making some design changes to the radio and my plan is to buy one of the new kits when they are available instead of trying to fix the one I have. Even though the radio doesn’t work I am not upset about it, I believe they are pushing limits and doing their best to create a great kit experience and a great radio for us.

I look forward to getting my hands on the next version of the QCX-mini and using it to make a lot of contacts with it.

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