Onboard audio suddenly went south

[seaweedsl]

It appears that the onboard audio card on my T42p is going out.

I used it last night 'twas ok, then put on some music today and it sounded like a bad radio station. AM. Or shortwave. Very distorted signal and background noise is almost as loud as the signal. I checked it with headphones and it's the same. Serious noise.

The internal speakers make noise even when muted. And I live on the ocean and have a fan running. Not a quiet place! You can hear the mute button as a little spike in the noise, but otherwise, it doesn't affect or reduce it.

I tested it with some USB speakers and they sound fine. I checked that the mic is muted and all that. Un muting the mic or line in increases the noise slightly. I downloaded the latest Soundmax driver and installed it.

I tried to test it on my linux pendrive, but it had no sound whatsoever. The sound worked in linux last week.

For the time being, I suppose I'll get a USB sound adapter and pull the palm rest to disconnect the internal speakers.

I imagine that replacing the MB is the only fix, but I thought I'd ask first and see if anybody has a suggestion.

Thanks,
Steve

[Norway Pad]

I don't know what can actually happen to the Audio device itself, and it that is likely to fail like this. But a loose Southbridge can give these symptoms.

The Southbridge (IO Controller) has to do with the IO (Everything In and Out) so look out for things like USB that stops working, or becomes slow, laptop freezing (IDE communication to HDD fails) or other abnormalities. That can verify that it is the Southbridge.

[seaweedsl]

OK, thanks. I remember that the Southbridge is another weak point. So far, no other problems to indicate it's I/O though.

This motherboard was a late version of the T42P that I installed about 3 years ago after a coffee spill killed the first one. Very reliable so far. It's mostly sat on the desktop the whole time. The thing is, I live on the ocean so it's likely to be getting an abnormal amount of corrosion, especially near the fan vent and ports.

I wonder if anybody has an idea why the volume control (mute) would introduce a spike in the noise, an event, but not mute it in any way. Almost certainly hardware anyway.

Any of of our EE types here want to hazard a guess ? Ray ?

[RealBlackStuff]

If sea salt corrosion is the cause, try another keyboard.

[seaweedsl]

If sea salt corrosion is the cause, try another keyboard.

Ah...good one! Maybe it's not the MB, but the volume/mute switches ! Easy enough to test. Got spare KB right here.

[poshgeordie]

Southbridge is V common but also check the side headphone / audio Out connector pads. If they are open circuit either due to corrosion or dirt in the connections etc which leaves them open then you'll not hear anything from the speakers.

Get a pair of headphones with the right stereo mini jack and insert and remove the jack a few times.

However re-reading your post in detail you say you have noise from the speakers even when muted. I have heard similar random noises which were cured with a SB chip reflow.

[seaweedsl]

Thanks for your help guys. I just finally got some time and swapped out the keyboard. It starts up but won't boot now. The hard drive light won't come on. Nor will it boot from the same USB which worked before.

Pressing F12 causes it to get stuck loading the list of bootable devices and never does come up with a list.

So, I/O seems to be failed. I presume that whatever movement I did pulling the KB was enough to take the SB out completely.

Oh well, I've got a spare MB. I wonder if it's worth trying to have this one reballed or just buy another spare on ebay when it comes up for $50 or less...

I suppose I should give the SB the pressure test when I pull the palmrest... just to confirm.

Steve