Problem with HDMI

So I'm building my first computer and everything was okay until I tried to plug the PC into my TV with a HDMI cable. Everything seems to be working but I can't get a picture to show up on my TV. Could someone give me a idea of what might be wrong?

Parts in PC

CPU: Amd FX 4200

Motherboard: Gigabyte GA-78 LMT

RAM: ADATA XPG V1

GPU: MSI R9 270

PSU: EVGA 500w

You have it plugged into the HDMI port on the GPU right? Not the motherboard? 

Have you any other device you can try to test display output and the HDMi cable?

Yes I have it plugged into the GPU. I have another TV I can plug it into and try but not a monitor. I've tried using several different HDMI cables I have just in case.