Lower voltage on Nano Output pins

Hello,

For my project I wanted to control some LEDs with the digital IO Pins of an arduino nano v3 but I got the folllowing problem:
I connected a LED to a IO pin and another identical LED to the 5V PIN. Each is connected to the ground with a individual 330 Ohm resistor.
The LED connected to the 5V is always on. When I set the IO Pin to high the other LED is on but its light is very weak. The voltage between the PIN and ground is 1.5V only.

What did i something wrong? Or is the "chineese Arduino compatible board from ebay" crap?

Luke

Problem solved.

I forgot to Set the Pin mode. So the arduino thought it is an PWM.