Bad output waveform. Any ideas?

Using Arduino General Electronics
1

Hello everyone,
I am having an issue with this arduino mega 2560. The output is not square. I was originally connected to Pin26 but after difficulty decided to try Pin13. Both outputs are identical. I have attached a photograph of the waveform. Any ideas would be appreciated.

Imgur

Photo is on-delay 500ms, off-delay 750ms using the "blink" sketch.

No other connections are made to the arduino except for the oscilloscope.

2

Is your scope set for AC Coupling instead of DC Coupling?
That's what a signal going thru a capacitor looks like.

3

WOW do I feel like a dummy!

Thanks man!

Prime example why the "auto" button should never be used...

4

Yep, sometimes it can getcha!