headphone jack not muting speakers reliably

[HFat]

My problem T61 (see my other thread) has developped yet another issue: more often than not, plugging headphones doens't mute the speakers. Sometimes the speakers will cut in and out on the slightest movement, indicating a mechanical issue with the jack (IMO).
At first I thought I was hearing things and then I used a headphone that's not sensitive and the problem became clear as day: both headphones and speakers were playing at the same time.

Does anyone know a fix for this short of changing the motherboard?
Perhaps someone knows about a mechanical trick such as using a particular adapter that's slightly larger than the norm.
Failing that, is there a way to manually mute the speakers in software or, even better, to turn their volume down a bit relative to the headphone voltage? I guess my only other alternatives would be to use an external souncard for headphones or to stick with very sensitive closed headphones in public.

[wap32]

Can you not disable the speakers in the bios?

I also know there is a way to mute the speakers via software, I have this in linux, I'm not sure how to do it on windows though.

You could also try to fix the jack yourself.

[HFat]

I don't know if the speakers can be disabled in the BIOS but I don't want to: I want to be able to use them when no headphones are plugged in!

How do you disable the speakers in Linux?

How would you go about fixing the headphone jack without voiding the warranty?

[dr_st]

How would you go about fixing the headphone jack without voiding the warranty?

If you have warranty, why would you bother yourself with it? Have them fix it.

[yak]

If it's a mechanical issue, you would have to take out the motherboard and either replace the headphones/microphone jacks or resolder them. Either way, if you still have warranty, the best option is to send it in.

[EAkamai]

Aloha! Sorry to state the obvious (perhaps you've already tried) but make sure that you can duplicate with another headphone set before making any more serious moves. I've even had some really high end headphones give me problems. If you find that is the case, many times a simple adapter fixes it.

[HFat]

You're right: it is obvious. I've tried a number of headphones and adapters from three different brands but maybe they were too "high-end".

The thing is, it's fairly random. Sometimes the speakers are muted and sometimes not, which would make a warranty repair dicey: they might claim nothing is wrong.