[spblat]

Can anyone offer any suggestions for troubleshooting my HTPC Audio problem? Here are some of the particulars of my situation.

• ThinkPad t60p; coax SPDIF port is on an Advanced Dock
• Windows Vista SP1 (but I had the same problem under XP; yesterday's upgrade to Vista was in hopes of solving this)
• Windows Media Center setup wizard recognizes the presence of the SPDIF output
• Windows audio setup recognizes the presence of the SPDIF output and claims it's working (screenshot below)
• Coax digital audio cable is good (tested this by using a SqueezeBox2 to pass audio through it into the receiver)
• Receiver is good and configured properly (tested this by using a SqueezeBox2 to drive the same input over coax SPDIF)
• Audio driver is SoundMAX Integrated Digital HD Audio 6.10.1.5500, dated 7/24/2007
• ThinkPad T60p BIOS is 2.22
• No sound comes out no matter what I do
• 1/8" analog input and output on the dock works fine

Here are a few screenshots.

http://spblat.googlepages.com/sound0.png
http://spblat.googlepages.com/sound1.png
http://spblat.googlepages.com/sound2.png
http://spblat.googlepages.com/sound3.png


There may be a clue in this last one. When I click "Test" my receiver "flaps" between displaying "Stereo" and "Dolby Digital" about twice per second, as though it's trying but failing to get a lock on the signal. Remember that the cable and receiver are tested good with another digital audio source.


Any suggestions? Thanks in advance, this is driving me nuts!

 

[cuti]

I ran into the same problem 2 months ago when I first time used the coax audio cable.

In your A/V receiver, you should force or change the audio channel from HDMI (if supports), AC3 5.1, fiber digital to COAX MODE

good lucks

 

[spblat]

Thanks for the suggestion. My receiver's about 4 years old. It has a control for auto-switching between a setting's analog and video input, auto or manual. I've hard-set it to digital. I wonder if the hardware is bad. This sucks!

 

[eminence55]

For testing purpose, if you have done this already, try find a DVD player with Coax and see if it plays through your amp.


if it does double check that the coax is in far enough on the terminal of the dock as some coax connectors don't have much room around them to put the cable on.


if still no go I would say there is a broken Coax jack on the dock as all settings in screen shot look fine ( although 48khz should be checked most likely)

 

[spblat]

Thanks eminence55. I had a Squeezebox laying around with a coax audio output, and it's working fine with the same amp and cable. I tried the "jiggle the cable" trick, actually with some high hopes, but to no avail.


I'm tempted to open the dock and resolder the connections on the coax port...the dock is out of warranty. Is there some other approach I can take to troubleshooting the hardware?

 

[spblat]

Last clue before I give up. I rewired the rat's nest and in the process tried another cable just to be sure. Out of nowhere, when I was done rewiring, I heard a 60Hz hum coming out of my home theater system. Since all my inputs are digital I found this weird and a little alarming. Investigation revealed the the hum was caused by having the coax cable connected from my laptop dock to the coax input of my amp. And get this, I was hearing the hum when the amp was set to other inputs, like my (toslink spdif) PS3 and my (coax spdif) Squeezebox. Disconnect the laptop coax, hum disappears. Weird. can't be good.


At this point any reasonable person would ask "are you sure it's not a composite video connector you're trying to use for digital audio?" But sure as anything the port is labeled "S/PDIF" and has an icon of a circle with an arrow pointing out of it.


Grunt! I think this is over, no solution.