Arduino nano - different voltages from different pins

Hi,

I have just found that I am getting different voltages from different digital pins on an Arduino Nano. D13 gives 4.1V, D12, D11 and D10 gives 1.73V. (I haven't tried the other pins).

The Arduino is powered from the computers USB.

Is this correct?

Did you remember to set the pins to OUTPUT?

What are they connected to?

ugh, no.

Many thanks for the quick reply. Off to slap myself.