Genuino UNO 5V pin is reading 0.3V So I was trying to set up the LCD screen that came with my Genuino starter kit when I noticed that the board screen did not power on at all, unlike a few days ago when it worked.

In order to verify that the UNO was delivering power I simply connected an LED in series with a 220&#x2126; resistor, between the 5V and ground pins. The LED did not power on.

I then, with the UNO still connected over USB, measured the voltage between across the resistor and LED and found it to be around 0.2-0.3V. Going further, reading the voltage between the 5V and ground solder connections on the back of the board and the reading is about the same.

I can power the LED from a digital pin that I set to HIGH, the issue seems to just be with the 5V pin.

Is there anything simple that I am missing (I hope there is) or is there likely a problem with my board? If there is a problem, could I use a digital pin to power a larger circuit such as that with an LCD or would the current supplied be too low?
There are a couple more places you can sample the 5V signal, see the photo here:



On the right, on the ICSP header, the pin marked VCC is also connected to the 5V signal. Try testing that.

(The other one is pin 2 of the ICSP interface for the USB chip, but the one on the right should be adequate for testing).

I don't know why you are mucking around with LEDs and resistors, just put your meter between Gnd and 5V.

I find sometimes that the hookup cable has failed, try testing that (or try with a different cable).