Asus A7V8X-X sound problem

My Asus A7V8X-X has an on-board ADI AD1980 AC'97 sound system. It uses jack sharing with SoundMAX. I use it to drive an Altec-Lansing computer 4.1 sound system in quadraphonic mode.

Everything was fine until I moved the computer system into another case to get better cooling. (The old one had lousy airflow.) I also installed a DVD burner (and kept my existing CD-ROM drive) when I swapped cases.

Line input is now completely inoperative; playing a CD on the CD-ROM drive produces a rear-channel output at the pink jack in 4-channel mode. The lime jack remains dead in all modes. There is no output at any jack in stereo mode. I assume that the DVD drive will do the same -- I haven't checked.

Has anyone run across anything similar? Got any fixes?

 

Seems that one stumped everybody. Major Geeks wasn't the only place I posted my question. Even Asus' discussion forum wasn't any more helpful.

I stumbled across the fix when I was browsing PC Mechanic's site following up a completely-unrelated Google link: see <http://www.pcmech.com/show/troubleshoot/743/>.

The clue was having switched to another case. The old case had a front-panel audio jack, but the new one didn't -- so nothing got connected to the FP-AUDIO header in the new setup.

Asus' manual for the A7V8X-X shows the FP-AUDIO header with two pairs of pins greyed over -- but doesn't say why. What's missing in the manual is an explanation that pins 5-6 and 9-10 need to be jumpered if there is no front-panel audio connection. The result looks like this: ::|.|

Jumpering those pins restored the on-board sound system to full functionality.

Google searches for corroborating information wasn't conclusive, but did suggest that this fix may apply to any on-board sound system using the AC'97 codec and a 10-pin FP-AUDIO header. But don't take my word for it -- do your own checking. I'm not going to replace your mobo for you if shorting those pins blows it up for you.