Yamaha HTR-5750 no sound when I turn to the DTV/Cable setting

If you are not getting sound on "Any" input except "multi channel" you have a bad DSP chip in the receiver.In short, you need a new receiver, it's a 500.00 repair. If you get sound on "All" inputs except "DTV/CBL" You need to get into the main menu of the Yamaha and select audio, toggle to input, then DTV/CBL and select "Auto". If you still do not get audio, it would be due to the version of HDMI software in your receiver. If it's under warranty, Yamaha will update hardware and software for you at N/C. If it's out of warranty, use digital coaxial or optical as your audio input for TV and run your HDMI directly to the TV. (The repair for this too would run 250-350) I hope I've covered all the possibilities. If you need further help, post a comment and I can help you more.