Raspberry Pi User Guide, 3rd Edition

Chapter 4

Troubleshooting

SOMETIMES THINGS DON’T go entirely smoothly. The more complex the device, the more complex the problems that can occur—and the Pi is an extremely complex device indeed.

Thankfully, many of the most common problems are straightforward to diagnose and fix. In this chapter, you look at some of the most common reasons for the Pi to misbehave and how to fix them.

Keyboard and Mouse Diagnostics

Perhaps the most common problem that users experience with the Raspberry Pi is when the keyboard repeats certain characters. For example, if the command startx appears onscreen as sttttttttttartxxxxxxxxxxxx, it will, understandably, fail to work when the Enter key is pressed.

There are typically two reasons why a USB keyboard fails to operate correctly when connected to the Raspberry Pi: it’s drawing too much power, or its internal chipset is conflicting with the USB circuitry on the Pi.

Check the documentation for your keyboard or the label on its underside to see if it has a power rating given in milliamps (mA). This is how much power the keyboard attempts to draw from the USB port when it’s in use. The Pi’s USB ports are not able to provide as much power as those of a full-size laptop or desktop computer. This can be a problem for keyboards that have built-in LED lighting, which require far more power to operate than a standard keyboard.

If you find that your USB keyboard may be drawing too much power, try connecting it to a powered USB hub instead of directly to ...