R-Pi Troubleshooting

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Revision as of 08:23, 28 April 2012 by Linker3000 (Talk | contribs) (General / Formatting)

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Back to the Hub. 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 / Mouse / Input Devices

Keyboard randomly repeats key presses

This is caused by inadequate power. Use a good power supply and a good power cable. 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)).

Memory Cards

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.

  • 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.

Networking

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 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.

Sound

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 in some applications

Device drivers for sound are still being developed. Please wait for the community to improve the situation.

Display

Video does not play or plays very slowly

It must be H264 or XVID. Device drivers for video are still being developed. The XMBC distribution is the only distribution with good video support at the moment. Please wait for the community to improve the situation.

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. RPi HDMI interference.jpg

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

To be added.

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.

On the other hand, a multimeter displays the average voltage. If short power-burst-requirements on the 'pi are not adequately regulated by the power supply the Raspberry Pi might still have power problems even though the multimeter gives the OK.

RPI Test Points.JPG Voltmeter.JPG