No sound with HDMI, sound with composite cable

Hi everyone,

I have a WD TV Live Hub, and an old LG HDTV. I have been using it for a while through HDMI, and suddenly a few weeks ago the sound stopped working (despite video being there).  I thought the HDMI cable might be problematic so I replaced that, but no luck. So I connected the Hub to the TV with a composite cable, and now on AV, I can watch movies with sound. Do you have an idea of what might be wrong? Is it possible to get the video through HDMI and audio through composite (I tried without luck)?

Thanks a lot in advance!

perhaps one of the pins on the tv hdmi input socket is dirty, got any servisol super 10 spray, or an ear bud with a little wd40 on it, you could give the tv input a little clean ans possibly the hdmi on the hub as well