Green LED blinks in a specific pattern
A good power supply that will supply 5 volts and at least 1 amp (5V 1A) is vital. A 5 volt 2 amp power supply can help some wifi USB adapters run more stable.
Note that the Pi has no BIOS, so nothing will be displayed on screen unless the Pi successfully boots!
Normal LED status
There are 2 LEDs near the USB connector:
- ACT: green - card status- flashes during SD card activity
- PWR: red - power - a power good indicator that goes off when power drops below 4.65V
Common Problems
- Red power LED does not light, nothing on display: The power is not properly connected. Unplug and re-plug the cable from the power-bank, and check whether the power-bank has energy.
- Red power LED is blinking: A blinking red power LED indicates problems with the power supply.The red power LED is wired to a voltage supervisor which kicks in when the 5V power supply drops below 4.63V. If it does, the LED will blink. Check your connections, cable, and power supply.
- Pi shuts down (or restarts) soon after booting up: This is caused by a power supply producing too low voltage. Try swapping power cable and power bank.
Rare Problems
- Pi boots sometimes but not always: With a known good power supply and known good SD card, the R-Pi boots occasionally, but other times shows only a tiny green flicker from the "OK" LED and it fails to start, even with no USB devices and no Ethernet. Low voltage or an improper SD card can cause it. Some SD cards will work until they warm up slightly, and then fail. It may also be an issue related to the SD memory card not making proper contact. Try to work with another Pi and contact the MedEasy technical staff.
- Kernel Panic on boot: Text appears on screen, but then hangs with debug messages. This can be caused by USB devices such as keyboards. Try again with nothing in the USB.