|Step-down converter based on LM2596. Note the damaged chip|
I happened to make a new cable for 12 Volts which had the polarities inverted - and puff - there was a noise and absolutely no response from the U3S. I feared that I had blown the entire circuit. As my power amplifier was turned off, only the 5 Volts supply was affected and upon inspection I found that the voltage converter had a destroyed chip.
Since since these step-down converter modules are so cheap on EBay, I had a spare. Luckily for me, the U3S worked as it should after the replacement. So the LM2596 can take a reversed polarity and sacrifices itself in order to protect the rest of the electronics. Nice!
This post first appeared on the LA3ZA Radio & Electronics blog.