R-Pi Troubleshooting

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This page lists the most common problems and suggests some solutions.

Power / Start-up
A good power supply that will supply 5V is vital. There is more information about power supplies and troubleshooting.

Red power LED does not light, nothing on display
The power is not properly connected.

Red power LED is on, green LED does not flash, nothing on display
The Raspberry Pi cannot find a valid image on the SD card. Check that you have correctly written a Raspberry Pi image to the card. See also, Known SD Cards.

Raspberry Pi shuts down soon after booting up
This is caused by a power supply with too low voltage or too high voltage. Or it could be the cable. See: On_the_RPi_usb_power_cable

Keyboard randomly repeats key presses
This is caused by inadequate power. Use a good power supply and a good power cable. Some cheap cables that work with a cell phone, cannot fully power the R-Pi. Some USB devices require a lot of power: most will have a label showing the voltage and mA requirements. They should be 5v 100mA each max, any more than this they must be used with a powered USB hub. Try unplugging every USB device except the keyboard (you should also note that some keyboards have built in hubs and can try to draw 1500mA (Pi can only handle 100mA per USB slot without a hub)).

Keyboard / Mouse interferes with USB WiFi device
Connecting a keyboard and/or mouse while a USB WiFi device is connected, may cause one or both devices to malfunction. On April 30 2012, there was a bugfix relating to USB sharing between high-speed (eg. WiFi) and full/low-speed devices (eg. keyboard/mouse). This problem may be fixed in kernels compiled after that date.

General / Formatting
If you are having problems setting up your memory card you might want to try erasing it completely - especially if it has been used elsewhere and still contains data / partitions.
 * Windows and Mac users can download a formatting tool from the SD Association: https://www.sdcard.org/downloads/formatter_3/


 * If you are preparing your SD card on a Linux-based system using the dd command, this operation will completely erase any existing data and partitions. Make sure you put the source image on the whole card, e.g. /dev/sdd, NOT /dev/sdd1.

Ethernet connection is lost when a USB device is plugged in
This is caused by inadequate power. Use a good power supply and a good power cable. Some cheap cables that work with a cell phone, cannot fully power the R-Pi. Some USB devices require a lot of power, so they must be used with a powered USB hub. Some cheap USB hubs suck power from the Raspberry Pi even if a USB power supply is connected.

I do not know the password to login
Please check the page http://www.raspberrypi.org/downloads for the correct username and password for each image.

Some programs refuse to accept my password
While using Debian, some programs may ask for your password but refuse to accept a valid password.

This is a fault in some Debian images and will be fixed soon. If you are using an image with this fault, enter the following command on the command line. gconftool-2 -\-type bool  -\-set  /apps/gksu/sudo-mode  true Please enter this command carefully, the spaces are important. The command should be accepted without any response or errors.

Sound does not work with a HDMI monitor
This is caused by some computer monitors which select DVI mode even if a HDMI cable is connected.

Enter the command sudo nano /boot/config.txt

If this file is empty or does not contain the config_hdmi_boost parameter, add the following line hdmi_drive=2

If this file already contains the hdmi_drive parameter, use the editor to change the value.

Save the edited file Press Control-X Press y Press [enter]

After exiting the editor, restart using the command sudo reboot

Note that you must use the correct reboot command to force a write of the edited file to the SD card.

Sound does not work at all, or in some applications
The ALSA sound driver is "alpha" and has issues, but some applications do work. If you are running Debian, try

cd /opt/vc/src/hello_pi/hello_audio make ./hello_audio.bin

to test analogue output. And

./hello_audio.bin 1

to test HDMI.

To test other applications, before "startx" type

sudo modprobe snd_bcm2835 sudo aplay

By default output will be automatic (hdmi if hdmi supports audio, otherwise analogue). You can force it with:

sudo amixer cset numid=3 

where n is 0=auto, 1=headphones, 2=hdmi.

Video does not play or plays very slowly
The only hardware-accelerated video player is the XMBC distribution and its command line variant omxplayer. H264 is the only hardware-accelerated codec, for playback. No hardware encoding is supported. Additional codecs were not purchased as licensing fees would have increased the R-Pi's price.

Can only get 800x480 resolution in LXDE (Arch linux)
Known issue with distro package as of 17-Apri-2012 - there's some missing boot config info. Creating a suitable cmdline.txt fixes it - type the following at the Raspberry Pi command line:

sudo echo "dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 root=/dev/mmcblk0p2 rootfstype=ext3 rootwait" >/boot/cmdline.txt

Interference visible on a HDMI or DVI monitor
This may be caused by loss of signal on long video cables. The signal level may be increased by changing a configuration parameter.

Enter the command sudo nano /boot/config.txt

If this file is empty or does not contain the config_hdmi_boost parameter, add the following line config_hdmi_boost=4

If this file already contains the config_hdmi_boost parameter, use the editor to change the value.

Save the edited file Press Control-X Press y Press [enter]

After exiting the editor, restart using the command sudo reboot

You may experiment with different values of config_hdmi_boost. Value 1 is used for very short cables, value 7 is used for very long cables. Note that you must use the correct reboot command to force a write of the edited file to the SD card.

GPIO
Remember that the GPIO pins are 3.3V logic level only, and are NOT 5V tolerant.

If you momentarily shorted the two end GPIO pins together (+3.3V and +5V), or a supply pin to ground, and the Pi appears to be dead, don't panic. The input polyfuse may have tripped. It is self-resetting after it cools down. Disconnect power and wait for 30 minutes, then try to restart.

Troubleshooting power problems
If you think you have a problem with your power supply, it is a good idea to check the actual voltage on the Raspberry Pi circuit board. Two test points labelled TP1 and TP2 are provided on the circuit board to facilitate voltage measurements.

Use a multimeter which is set to the range 20 volts DC (or 20v =). You should see a voltage between 4.75 and 5.25 volts. Anything outside this range indicates that you have a problem with your power supply or your power cable.

If you have not used a multimeter before, see these [basic instructions]

Note: Even if the multimeter shows the correct voltage, you may have some power supply problems. A multimeter only displays the average voltage. If there are very short-lived dips or spikes in the voltage, these will not be shown by the multimeter.