If you’ve been following along on my YouTube Channel, you’ll find that I’ve been having issues getting any sideband cancellation with my QCX Mini. I’ve been troubleshooting it. See the video below for some information about the troubleshooting. But first, remember C38?
C38 Woes: Root cause found!
On a few QCX Mini’s, C38 blew, causing the 5V regulator to short, which rendered some brand new radios inoperable. Some were quick to blame the switch to SMD parts or to go a bit overboard with their accusations. But Hans did some forensic work, and found the cause, mentioned in This Thread on the QRP Labs groups.io page.
The cause? The factory used a part rated for 10V, not the 25V part that Hans specified in the Bill of Materials! With higher voltage, capacitance goes down, and failure ensued. Hans has made it good and anyone who lost a QCX Mini is being taken care of. All kits are being shipped with the requisite 10uf capacitor so that this doesn’t affect others. The next batch of boards will use a through-hole part.
Here’s the video I mentioned at the outset. Please have a look and let me know: What do you think might be the cause? The more brains the better. Comment here or on YouTube. Thanks and 73!
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