Static Shock killed my Sound Card?

[nestlewater]

No he didn't throw a manhole cover at it!

So this winter, air has been very dry. And static is everywhere with carpet. Each time I flip a light switch in the house I'd get shocked by the screws that attaches the cover.
Throughout the winter if I shuffle my feet accidental or habitual while wearing ear-buds, I'd notice a small shock from my ear-buds to my ear. It wasn't terribly painful, So I just let it go.
Recently My soundcard just pooped out.
If I turn the sound volume down to very low, it comes out ok.. but still with much"" higher noise floor than before. When I adjust the volume higher, it just completely distorts.
Now, Since all the channels are still outputing, I'm guessing it's probably just the oamps or a few of the main caps.
What do ya'll college degree EEs think?

TIA

 

[Harvey]

It could be an amp, or a single transistor or one or more of the FET switches in the digital volume control. If you have schematics and you know something about tech servicing circuits, you may be able to find the problem, but unless the manufacturer has a very friendly service policy, or you've got good eyes, better hands and some knowledge of reworking surface mounted parts, you're pretty much SOL. Unless it's a very expensive sound card, the cost of paying competent service tech to repair it could be more than it cost.

Good luck.

 

[nestlewater]

Hmmm. I did check the surface of it VERY carefully, and there isn't anything apparently wrong. So guess I'm SOL then. It's an old audigy 2zs. Hope to get one on ebay, fingers crossed.

 

[esun]

When we say "check" as electrical engineers it usually involves use of a power supply and a multimeter at the very least. Visually you'd never know something was damaged unless it was pretty catastrophic.

The damaged component was likely the last one along the chain to the output (probably a buffer or something for an amplified output). It might be fun to try to repair it just as an exercise, but if you're not a EE (or don't have at least some knowledge of electronics) and don't have access to lab equipment, then it would be unfeasible.

 

[mindless1]

When you observed static, you had generated a charge through friction, then dissipating it on something grounded. With your sound card it is not likely you caused such a situation except a discharge to the case ground which shouldn't be a problem. You would need a piece of metal protruding out side of your system, without any ground near it, and then dissipate the charge through that cable connected to a non-ground trace on the card.

The most likely thing that happened is a driver or windows bug that messed up the audio signal levels, put them beyond the capability of the components and/or their supply voltage(s). Therefore, the best thing to do now is try the card in another system, or do a reinstall of the driver, check windows mixer settings, all cabling, and lastly a clean reinstall of the OS (to a different partition or drive if you don't want to disturb the existing installation just yet). With the former attempt you might also need to manually clear out any remaining registry settings after having uninstalled the driver. I'm not sure if DirectX problems would surface like this, but to be thorough I'd also install the latest DX.

Think through any system changes that might've occurred just prior to the onset of the problem. I could be leading you astray, it is possible the card itself is damaged but unless you had been manipulating the parts or cables to cause it, merely having static electricity generation within that environment is not likely to damage a card within a large grounded computer case, having a grounded slot bracket, and having cables that contain a ground lead. If the card was being handled outside the system without the handler wearing an ESD strap that would be a different matter.

Otherwise an AC power surge seems just as likely to do damage, but before I forget, are you certain it is not the speaker amp causing the problem instead of the sound card? Integrated speaker amps sometimes have a tendency to pop their capacitors which would correspond to increasing distortion at increasing output levels, increased current requirements from the PSU.

As for damaging something in the output signal path, each channel has it's own transistors after opamps (that are probably handling 2 channels each). If a static charge came in on one line it could damage that channel but would not effect all the other channels too (or at least be extremely unlikey to be enough to do this but have them output sound at all after such an event). The capacitors are not going to be a factor, if one of those was damaged to an extent that could cause such distortion, it would have blown up or vented already.

 

[Gunbuster]

Are you sure this is not just a coincidence? Could be the classic creative labs PCI latency crackle.

 

[nestlewater]

Originally posted by: Gunbuster
Are you sure this is not just a coincidence? Could be the classic creative labs PCI latency crackle.

Noooo, the sound is completely distorted at high volume.

 

[mindless1]

I think Gunbuster meant, coincidence that the sound is distorted at high volume and you noticed other static discharge events. One does not suggest the other.

 

[nestlewater]

Originally posted by: mindless1
I think Gunbuster meant, coincidence that the sound is distorted at high volume and you noticed other static discharge events. One does not suggest the other.

Umm.. Front left channel is very mute, while right is working fine, when I crank up the volume both channels distort. Significantly more noise than prior to the "final event". every channel basically sounds terrible. At higher than 1/4 volume The output is completely distorted and indistinguishable.

 

[mindless1]

Ok, but did you do any of the things I'd suggested already? If it is a hardware defect, unless you can source discrete parts and solder them on, it doesn't really even matter what caused the fault, only that you find which part is the fault and drivers plus OS are still possible problems. If the input level is too high it is expected you could have distortion, and that it could vary a bit from channel to channel based on the design and exact levels input to any stage.

To reasonably expect static discharge to have caused damage, there would need be a specific event shunting high voltage through the card to ground. Every winter, this one included, plenty of us have lots of static electricity in our environments but few and far inbetween have parts inside a grounded computer case damaged by it. Without a specific strange event.

If you're dead set on finding the answer you can put a board out on a desk, mount the card and start taking AC voltage measurements at various points along the analog path, that will tell you about the output stage between the DAC and everything analog that comes thereafter meaning opamp and transistor pairs, but it won't tell you much if you have high digital bit values already before the DAC.

 

[blahblah99]

Originally posted by: nestlewater

Originally posted by: Gunbuster
Are you sure this is not just a coincidence? Could be the classic creative labs PCI latency crackle.

Noooo, the sound is completely distorted at high volume.

My guess is the opamp inputs got screwed and its input bias is out of spec, hence the additional noise.

 

[nestlewater]

Originally posted by: blahblah99

Originally posted by: nestlewater

Originally posted by: Gunbuster
Are you sure this is not just a coincidence? Could be the classic creative labs PCI latency crackle.

Noooo, the sound is completely distorted at high volume.

My guess is the opamp inputs got screwed and its input bias is out of spec, hence the additional noise.

I just ordered lm4652ma from national, Hope you're right. fingers crossed

 

[mindless1]

The DAC right before the opamp should be good for a few mA, you could've tack-down soldered a pair of leads at the opamp input pin solder pad & ground, then put a connector on the other end to see how that sounds through amplified speakers or not-terribly-low Z headphones. To reduce the chance the leads tear off the solder pad from their weight or being pulled upon, it would be good to tape them down or put a temporary bead of hot glue down to secure them.

If it's not distorted then it seems a part after the DAC is bad. If it is distorted, the DAC or something before it is the problem. Same applies to tacking the leads down at the opamp output pin, if you desolder the transistor following it in the output stage.