On 12/3/2020, Hans Summers of QRP Labs released the QCX Mini- a truly miniature 5W CW transceiver. By the December 7, all 997 units were sold! It was definitely exciting to see the response to this new product, and after having built most of my own QCX Mini, I can confirm- it’s an incredible little radio! I’ve got some QCX Mini construction tips to share with you. But before we get to that:
Critical QCX Mini Modification Advisory
On 12/14/20, Hans posted on the QRP Labs Groups.io page a post with the following subject:
QCX-mini critical modification advisory
Four QCX Mini builders had their QCX Mini’s go up in smoke upon power up after having rapidly cycled the power, causing Magic Smoke to be released and leaving them with non-functioning QCX Mini’s. The problem was found to be that the SMD capacitor C38 was insufficient. You see, during testing, Hans did not rapidly power cycle the radio, as that’s not a typical mode of operation. But, he has since decided to add rapid power cycles to his litany of tests that he runs on new products.
The fix is very very simple: Solder in a 10uf capacitor between a leg on the voltage regulator and to a leg of diode D33. The manual outlines the fix and future QCX Mini’s will include the fix on the PCB.
What you Need to do
Perhaps nothing! If your QCX Mini hasn’t shipped yet, then you’ll be getting a 10uf capacitor with your kit, and you’ll just install it as part of the construction.
If you have already received your QCX Mini, do not fret! You need to add any capacitor greater than 10uf and rated for at least 16V as shown on Page 68 of the updated manual. As you can see below, it goes behind the power connector. If you don’t have a such a capacitor, then ask around. These are very easy to come by and can even be salvaged from old portable radios, TV’s, and other analog electronics. And, some hams have even offered to ship the needed capacitors to those in need. Check out the QRP Labs Groups.io page to find such posts. Kudos to them for stepping up!
If it’s not possible for you to source one yourself, contact QRP Labs and Hans will make sure you get one. HOWEVER before you do that, Read This Post and consider ordering a capacitor on Mouser or Arrow.com. You got a world class radio quite inexpensively, after all.
QCX Mini “Mini Tips” on YouTube
While constructing my own QCX Mini, I decided to take a few minutes and share some of my own consstruction tips, shortcuts, and general ideas. Each video is only 2-4 minutes long, and the hope is that you will be able to have an easier time in building your own QCX Mini. Be sure to subscribe to the YouTube channel if you haven’t already. Here’s the first video, and each video has a link to the next at the end:
If you have any of your own tips, please leave them in the comments either below or on YouTube. Thanks!