Some time ago, I ordered and received the RPi 2,. ordered and imaged a new SD card and found the board not booting.
Having been using a RPi 1 with power supply, monitor, mouse and keyboard and never seen any problems starting,. I expected
the new board also to boot with the new SD card and the rest of the hardware.
After spending quite some time with changing to another RPi 2 board ( exchange ) different SD cards, I had the conclude that
my problem most likely had to do with the the power supply.
All the used SD cards and hardware did work with The RPi 1.
Up to this point both boards did not work while the RP1 1 never failed to boot.
The power supply I was using provided about 5.4 V measured on the miniature USB connector on the board. Changing start sequence
had no effect, 110 Volt first, USB switching with Power Supply already powered up. No variations in the board voltage were noticed.
during the start-up.
The power supply ( Chinese switching ) had a relative thin output power cord ( by closer inspection )
Finally, by using an home built power supply with adjustable output voltage and the heavier gauge output power cord, I got both computer
board to work with all the SD cards I had required in the previous process.
Not having an oscilloscope available, I was not able to look for any non wanted effects at the time of switching on the RPi 2.
My final conclusion is that the RP1 2 is much more sensitive to possible voltage changes than the RPi 1 during start-up and booting
With the adjustable 5 V power, I experienced no problems running between 4.5 and 5.5 V input to the board.
Wished I had known this a little earlier....!
Rein Smit
