Adjust the output with a multimeter before you connect the load. Modules often leave the factory set to a voltage that can damage a 3.3 V or 5 V board.
What the message means
The module has a trimmer that sets the output. The input must be higher than the output by a margin, and the current must stay within the rating.
Fix it in this order
- Connect the input supply only, with nothing on the output.
- Measure the output voltage and turn the trimmer until it reads exactly what you need, for example 5.0 V.
- Turn the power off, connect the load and power on again.
- Keep the input at least a couple of volts above the output.
- Check the module current rating and add a heat sink or reduce the load if it runs hot.
- Check again after the load connects, since the voltage may sag.
If you see this, do this
| You see | Do this |
|---|---|
| Output higher than expected | Trimmer not set before connecting. |
| Output drops under load | Input too low or load too high. |
Related
brownout, robot battery guide.
Last reviewed: November 2026. These are the usual causes and the order that finds them fastest. Test on your own board; clones and cables differ.