jack detection signal?

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There's a front panel audio header on my Intel system, and it seems like whatever signal tells the mobo a mike or headset is connected is not getting through. When I plug in the headset, the rear-connected speakers do not mute. When I plug in a mike, I get nothing. Everything works fine through the rear panel connectors.

The cable connecting the front panel audio header to the mobo has a pinout diagram showing "sense1" and "sense2" conductors that somehow let the mobo know when a mike or headset jack is plugged in.

Question: How can I test if sense1 and sense2 are working properly? I would assume they just go to ground when a jack is inserted. That would help me eliminate the possibility of a software issue. But when I perform that test, I get no continuity to ground. Am I testing this correctly?
 

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Which MB do you have exactly? Jack sense in Intel HDA is not mechanical, but codecs measure impedance of the input/output pins and make conclusion about the connected device (line-in, microphone, headphones, etc.). Codec datasheet specifies respective impedance ranges.
 
The mobo is an Intel DP35DP, and it does indeed use HDA. What I plugged into the front panel audio header jacks was a "dummy" 3.5 mm stereo minijack with bare wires attached. I wanted to test L/R channel continuity from those jacks through the cable to the mobo. That continuity was fine.

As per your suggestion, I went to the Intel site and searched their tech documents. It seems you're correct about the mobo looking for an impendance range, rather than a simple open/closed to ground like I assumed, but could not find any range values.

Given the symptoms described in my first post, I'm now starting to suspect it could be either a bad audio chip or a faulty front panel audio header. The headset and mike work fine on other machines, and in the rear panel jacks of the Intel machine.

I'm running out of things to test. I did a fresh install of XP and eliminated other peripherals. I doubt this is a software issue. And the machine is less than a year old. Any suggestions would be most appreciated. Thanks.
 
The Intel HDA controller is a part of the southern bridge ICH9. You need to consult datasheet of the HDA codec STAC9271D, which communicates with the controller using the HDA protocol. See page 21 of

http://pdf1.alldatasheet.com/datasheet-pdf/view/199334/IDT/STAC9271D5TAEyyX/datasheet.pdf

I would check for correct connection, e.g. http://forums.techguy.org/hardware/399052-solved-front-panel-audio-problem.html , including the front-panel end of the cable. Also audio drivers could be the culprit, all these functions must be activated/configured by the driver.
 
Thanks for the tips. You were correct about the audio drivers. I may have just solved the problem. The original drivers (v1.0)were from SigmaTel. I linked to the IDT website through Intel and got new drivers (v1.22) from IDT. Everything now works as it should.

Now I can move on to phase 2 of this troubleshoot. When I originally lost my front panel header connectivity, I had installed a Creative X-Fi HD audio card. Working my way backwards to eliminate possible conflicts, I first had to establish that this header worked with the onboard audio. It does now.

So that seems to point to the X-Fi as the source of the problem, but I won't know for sure until I reistall it. And update its drivers.

Question: Will the sound card totally take over the processing of the audio stream, and use its own codecs? Or will it still rely on this new IDT codec that was needed for the onboard sound?
 
Well, you were right about that. With the sound card installed, I lose functionality in that front panel audio header again. If you read this whole thread, you'll see where I started.

At this point, I'm forced to conclude there is a fundamental incompatibility between that X-Fi Extreme model and the front panel header (which is Intel). I've read about this happening on other forums, but never with respect to this specific card.

What's weird is that header is just jacks ... no other circuit components. There must be an industry standard there somewhere. ANY sound card should work.

That's why I spent the time to try new drivers for the card. Still won't work with the header. Rear panel works fine.

What I'm considering now is just blowing off the whole sound card. The mobo has an HDA system on it, and I know it works with the front panel header.

What do you think about that idea? I'm not a musician, and the only sound processing I do on that machine is basic audio and video editing, and I'm fine with 2-channel stereo. I don't really need to create or mix music. Would you not agree that the onboard sound systems these days are good enough to obviate the need for a sound card, at least for people like me?
 
Did you check http://www.tomshardware.co.uk/forum/page-252993_10_0.html ?

IIRC X-Fi supports HDA compatibility mode. In linux the Intel HDA driver used to be the only way to run the card before native X-Fi drivers appeared. However, the mode must be properly switched via drivers. I doubt the windows X-Fi drivers from Creatïve do that, the native mode supports a lot more functions. It would not be surprising if the native mode did not support automatic headphone detection on the front HDA header (which is a typical HDA functionality). That would correspond with the suggestion to switch the headphones manually in the driver.

Just my 2cents, I have never played with X-Fi.
 
That link pretty much confirms what I was suspecting. I'll mention it to Velocity Micro when I talk to their tech support tomorrow. My system is still under warranty. Maybe they can just send me the properly pinned connection cable to attach that front panel audio header to my X-Fi.
 
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