Radeon HD 6670 can't use HDMI

Hi all, I am using Radeon HD 6670. Recently I bought Samsung UA28K4A5AJ, after plugged HDMI, no signal can be found by the TV. I plugged DVI to original monitor and I found that Samsung is detected by catalyst control center, only the TV can't find any signal.

 

I plugged the HDMI line to onboard display card (my MB: MSI H81I) and it works just fine, so I am pretty sure the HDMI line is okay.

 

Can anyone help me to solve this problem?