How can I tell if an audio card is fried (and how to fix it)?

[agregate]

I have a T400 that I bought last year and I've never been able to get the speakers to work. If I plug in headphones, then the sound is perfectly fine without any crackling or noise.

When I purchased it, it had Windows 7 and now runs the latest version of Linux. I've tried spamming keys at the BIOS to get the speaker to beep, I ran `beep` in FreeDOS, I've tried using it like normal with PulseAudio/ALSA and I still can't get any audio.

The thing is, the PCI slot is being detected fine and it says its for Intel Audio. `alsamixer` also shows me audio card information so it looks like it should be working?

I thought maybe the old speakers were blown so I bought new ones and nothing has changed. It may sound stupid, but I also took a AA battery to the old speakers and flicked a wire across the terminals and the speakers indeed made a noise so it surely must be the card and not the speakers?

Is there any way to diagnose the problem in hardware and not just software? How do I know for certain that my card is fried? Can I pull the chip off and solder on a new one? Which chip is it on a T400? Where is it? These are all questions that I have in mind...

[ajkula66]

Is there any way to diagnose the problem in hardware and not just software?

You've pretty much done everything that I would've at this point.

How do I know for certain that my card is fried?

It sounds to me like it is, at least the side that outputs to the speakers.

Can I pull the chip off and solder on a new one? Which chip is it on a T400? Where is it?

No. You'd need to replace the motherboard.

Good luck.

[dr_st]

Since the sound through the headphone jack is fine, this suggest that the audio producing portion of the chip is intact. Given that two sets of speakers experienced the same issue, I would say the problem is somewhere in the circuit that detects something being plugged into the headphone jack. It seems to think there is always something there, even if there isn't, and mutes the speakers accordingly.

[agregate]

You've pretty much done everything that I would've at this point.

No. You'd need to replace the motherboard.

Good luck.

At least I know I'm not going crazy or doing something wrong. It is a shame, but I may just have to live without sound. Thank you for the response.

[agregate]

Since the sound through the headphone jack is fine, this suggest that the audio producing portion of the chip is intact. Given that two sets of speakers experienced the same issue, I would say the problem is somewhere in the circuit that detects something being plugged into the headphone jack. It seems to think there is always something there, even if there isn't, and mutes the speakers accordingly.

Hmm... Sometimes (I'm talking like 1/10 times) when I plug the headphones in, ALSA doesn't switch over from the (dead) speakers to headphone mode, and I have to unplug and replug them. This is probably a configuration issue, but could this also be a symptom of what you are describing?

[kfzhu1229]

I would say the problem is somewhere in the circuit that detects something being plugged into the headphone jack. It seems to think there is always something there, even if there isn't, and mutes the speakers accordingly.

From my experience I totally agree with you.
My friend came to me a few weeks ago saying his laptop speakers are not working and nor is the mic (because on newer laptops the mic is on the same headphone jack)
And yes sure enough he has the extreme luck of a piece of drying crystal stuck right inside the headphone jack! He's extremely fortunate that headphone jack has holes on the back so I just pushed a tiny screwdriver through the back and it came right out!

[rkawakami]

Hmm... Sometimes (I'm talking like 1/10 times) when I plug the headphones in, ALSA doesn't switch over from the (dead) speakers to headphone mode, and I have to unplug and replug them. This is probably a configuration issue, but could this also be a symptom of what you are describing?

Your description of the audio problem and the steps you have taken so far points to several possibilities: a defective headphone jack or a couple of components associated with it, a bad switching transistor or a short in the docking port. Inside the headphone jack assembly there are 2 "switches" that detect when a plug is inserted. Only one of them is actually used to inform the audio circuitry that headphones are plugged in. This switch controls a transistor which in turn tells the audio IC to mute the speakers. Any one of those components could be bad and that might prevent the speakers from activating.

From what I can tell, there is also a connection to the docking port that if shorted to ground, will prevent the speakers from operating. I don't know if that would also affect the laptop in BIOS mode (your thrashing of the keys to get a beep). In any event, this would be the easiest thing to check first. You'll probably have to push the plastic piece that hides the contacts down into the docking port but you should be able to see the gold traces. Make sure that they are all uniform and there's nothing in between adjacent contacts.

The other things that might be a problem will require a disassembly of the system in order to get down to the motherboard. Depending upon where the components are, you might have to actually remove the motherboard from the base. If inspection of the docking port doesn't reveal any problems and you feel comfortable with the teardown, grab a copy of the Hardware Maintenance Manual from the link at the top of the page and start reading.

[Sweater Fish Deluxe]

If a short made the headphone jack always seem to be plugged in, that would show up in PulseAudio Control. Headphone output would always show as plugged and the speaker as disabled. The speaker would also appear in ALSAmixer as hardware muted (MM). I assume OP would have noticed this.

My guess would be a dead surface-mount component in the speaker circuit. If that's what it is, it might be fairly easy to track down if you have experience with a multimeter. Start at the speaker connection and work back.