Problem getting sound through Yamaha RXV1500

On many AVRs you need to "assign" the various digital inputs. This is usually described in the AVR's operating manual. What this means is that the AVR needs to know which digital input you "assign" to which input you choose - like VCR2. You need to go into the AVR's setup menu to do this.

In some cases some of the digital inputs are "pre-assigned". If you have one of those available, you can try that or simply as a test use one of the known working inputs to make sure that you can hear the sound from the STB - say the CD input which you have working?

You may also need to go into the settings for the STB and tell it to use "Dolby digital" and not HDMI or Other for the audio - press the settings button twice and go to the audio settings. What's the make/model of the STB?

it's the Cisco 4642

I changed the output to Dolby Digital and no change. I looked at the inputs, my Marantz has Digital 1, Digital 2, etc. and I have set those up before but on the Yammy, the seem to be pre-assigned. I'll recheck.

I am thinking it's still the cabling. Is the input to DVR/VCR2 via the digital audio cable (#9 on image, bottom left) the right input?

You should be able to get the audio from input 9 by switching to input "DVR". This assumes you don't have anything else also connected to that input name. I thought the 4642 had an optical output also. If that doesn't work, try the known working CD input to see if you get sound from the STB if you switch to "CD" - make sure the STB is on and tuned to a channel with audio.

looks like it does have the optical out but I don't have the cable. regardless the coaxial digital audio should work.

http://www.cisco.com/en/US/prod/collateral/video/ps8611/ps8612/ps8620/7016860.pdf

nothing else should be assigned to it but i'll recheck them.

I'll try the CD option as well.

My CD is connected via the RCA in's, not via digital coaxial. It's almost 20 years old and still works great and only has RCA out's. So I don't know that I can test it using that method.

I am stumped, I have tried putting it in the DVD digital in and assigning that but it doesn't do anything.

Is there a way that I can test to see if any sound is coming out of the STB via the digital audio out?

Plug the STB coaxial audio cable into the CD input, unplug the CD analogue cables, just in case, switch the AVR to CD. Do a reboot of the STB and make sure it's set to Dolby Digital, not HDMI or other. If still no sound, switch to Other, then back to DD. Try a different coaxial cable in case it's bad (any RCA cable will work).

If you get that working, then try the DVR input.

Make sure that the AVR has the audio option set to "auto" which means it'll take the "highest value" signal (digital over analogue). Make sure it's not set to "analogue". I can't be sure but I believe this is done through repeated presses of a button like "audio" or in the audio setup menu.

Well nothing like a bad cable to think you are losing your mind. Is there any downside to just running the RCA instead of the coaxial?

Nope, an RCA cable is basically a coaxial audio cable with minor differences, that are usually inaudible. Try to find a half-decent one, or if you have a composite (yellow) or single component cable lying around use that. See:

http://www.digitalhome.ca/forum/showthread.php?t=76085 Cables & Connections

Great, thanks and thanks for all the help.