Hardware Reference
In-Depth Information
until you can isolate where the problem is. You'll see the same principles apply to inding
faults in your programs later in the topic. It's a good idea to simplify to the simplest possible
coniguration irst - unplug the keyboard, mouse and/or display to see if the Pi shows signs
of life - and then add things one by one. When you are suspicious of what might be at fault,
try borrowing a known working replacement from a friend or try the suspected faulty part in
theirs. his way, you can eliminate parts until the fault is found.
Common Problems
he majority of problems in getting the Raspberry Pi to work are easy to ix. he following
subsections describe some of the issues that you might encounter with the Raspberry Pi and
how to troubleshoot them.
No Lights Come On
If none of the lights come on when you power up your Raspberry Pi, the power supply may not
be providing the required 5V. If you have a meter, you can measure the output as detailed in
the subsection “Power Problems”; if not, try borrowing a friend's that you know works.
Only the Red Light Comes On
If just the red light comes on, then the Raspberry Pi is getting some power, but it isn't booting
the OS. Make sure that the SD card is correctly inserted, and then check that it is correctly
imaged. Even if the card is correctly imaged, it may be that the card isn't compatible with the
Raspberry Pi. If possible, try another card that is known to work, either from a friend or by buy-
ing a premade card. Also check that the power supply is providing enough power.
No Monitor Output
Check that the connector to the monitor hasn't come loose and that if your monitor has a
choice of inputs that the correct one is selected. Normally, there is a switch on the front that
cycles through the input sources. With some monitors it is necessary to have connected the
monitor to the Raspberry Pi before powering it up. If you are still having trouble, try a difer-
ent monitor and cable.
Intermittent Problems
If the Raspberry Pi freezes or resets, particularly when you do something that demands more
power (such as graphics-intensive work or adding a peripheral), then it's likely the power
supply isn't providing enough power.
Power Problems
he Raspberry Pi needs more power than some micro USB power adapters can provide. It is
certainly more than what's provided by the output of most computer USB ports. As the
