When I connect my Humax to my Yamaha surround sound via a HDMI cable I have sound but the picture drops out after 5seconds.

[carriebondoux]

No picture when connecting a Humax to Yamaha surround sound. Sound but no picture

 

[americanaudiophile]

If you have a Yamaha AVR you might need to assign the HDMI as your video source for that input in the input set up menu.
Check the manual.