Stand-by audio oscillation

merry · Jan 15, 2003, 06:55 AM

I use ABit's ST-6, onboard sound.

When I turn the rig off, after something like 15-30 minutes, there's a small 'thump' in the speakers and...

In the begining there was a continuous tone in the KHz range, not very loud. For a couple of days it has turned into a very low frequency oscillation, audible thumps 1s apart.

Anybody else experienced this?

DcibeL · Jan 17, 2003, 10:42 PM

Sounds to me like you have a bad capacitor on your motherboard that won't discharge. As long as it doesn't make any unwelcome sounds while the computer is on, and the computer is running reliably, I'd say there's not much you can do. If the capacitor is being used for voltage regulation, there is no problems with it not discharging, just as long as it doesn't short out, then your computer will crash.

Have a look at your motherboard and tell me if any of the caps have some brown goo on top of them. If there is, this is definately the case. However, if there isn't it doesn't necissarily mean that your caps are in good working condition, it just means they're not leaking dielectric fluid.

I could be completely wrong too, I'm just an electronics student, not a bloody rocket scientist.

merry · Jan 20, 2003, 10:22 AM

Thanks, I am an Electronics engineer - nice to meet someone in the business, too many damn poets (sw people) in these hw boards

Btw, you know the difference between s/w people and h/w people? Well, the latter wash their hands before they pee...

Yes, I also suspect a cap - I'm not a rocket scientist either, neither a computer expert, but it definitely looks like some cap discharging. Although 15-30' is a bit long. And the result is definitely some sort of instability (oscillation), which is weird, I had no idea the audio stages are powered during standby - I thought only the chipset was. Btw, lately the oscillation has turned into a high frequency, now what I hear is a hiss. No significant environment temp variation.

My strongest fear was of a PS related problem - there is something else... During a game of Age of Kings (my favourite) the PC sometimes shuts down unexpectedly, and I have to disconnect the PS (switch on the back of the PC) in order to be able to start it again. 3D games work, so I don't believe it's video related. I didn't mention it, as there was a thread a while ago discussing this problem - somebody else had that on two PCs, AMD based - and there was no solution.

Thanks for your input, and stay tuned

ToshiroOC · Jan 20, 2003, 10:28 AM

Quote:

Originally posted by merry
My strongest fear was of a PS related problem - there is something else... During a game of Age of Kings (my favourite) the PC sometimes shuts down unexpectedly, and I have to disconnect the PS (switch on the back of the PC) in order to be able to start it again. 3D games work, so I don't believe it's video related. I didn't mention it, as there was a thread a while ago discussing this problem - somebody else had that on two PCs, AMD based - and there was no solution.

Thanks for your input, and stay tuned

I had a friend with the exact same problem, and it turned out to be a faulty PSU - his kept rebooting spontaneously, and sometimes wouldn't cold boot - replacement of the PSU fixed 99% of his problems. Oh, and Merry, Mac Daddy mentioned that he knew you RL. Do you both work in the same place? I remember him saying that he was deeply involved with x86 asm, which could be related to whatever an EE does (I really want to be either an EE or CSEE... what do you recommend in terms of fun/$$?)...

ToshiroOC

merry · Jan 20, 2003, 11:46 AM

Quote:

Originally posted by ToshiroOC
Oh, and Merry, Mac Daddy mentioned that he knew you RL. Do you both work in the same place? I remember him saying that he was deeply involved with x86 asm, which could be related to whatever an EE does (I really want to be either an EE or CSEE... what do you recommend in terms of fun/$$?)...

ToshiroOC

MacDaddy and I have the same background - at least very similar - and almost the same age, but he's Canadian, I'm Romanian. Hurray for the Internet on this one.

CSEE sounds like Computer Science - hm - EE (?) to me... maybe you could be more specific?

Anyway, we live in such different parts of the world, that I couldn't dream to recommend anything. However, I think future programmers will be very hardware conscious.

As things go now, it's pretty easy to take some visual compiler and make some idea work - you don't need to care about the resources, there's plenty in every PC, and if they're not enough, they will be next year.

However, all resources are not infinite - remember coal, or gasoline? At some point there will be a serious slowdown in miniaturizing, and Moore's law will cease to function.

And they will buy s/w that goes easy on the resources, like they buy cars that don't use much gas, and there's a lot of research on the electric car going on, too.

My guess is asm will be the way to go - it's as close to the machine as you can get. And you don't have to be paranoid, C/C++ work pretty good (efficient appz) as I'm told. But...

A 6K notepad...

Anyway, this won't happen soon, and mind that I'm not a programmer... it's just a thought. And thanks for trusting me.

PS I don't think engineering as being fun, and it certainly doesn't bring a lot of money in - but there is a sense of acomplishment, you know, of doing 'real' things, that work - I'm affraid it's the only highlight to this proffession.

DcibeL · Jan 20, 2003, 10:10 PM

I was going to go into computer programming, but the people in that field are just too, ummm...Geeky! As much as I like programming, I would physically explode if I had to work with those kind of people all my life.

So my next desiscion was electronics. I'm not taking engineering, but a Technologist course at a trade school. We get to do a lot more building things, and less theory. Now that I've been in school taking this course for while I really think I made the right choice. I absolutely love building electronics, and I won't end up in a cubicle for the rest of my days

I've just started taking Digital. We haven't done any work with ASM, but we will in the fall. For now we are programming IC's with CUPL. Pretty fun stuff I'd say!

Did you have a look at your PSU Merry? Sounds like the only other thing to check.

merry · Jan 21, 2003, 11:22 AM

Yes, I thought bad thoughts of my PSU... it's still under warranty, so no opening. And I also don't have proper tools at home, to make any measyrements.

It's a cheap PSU, but 300W (maybe 350, don't remember). The thing is I should move my posterior and borrow a PSU from somebody, to see what happens - but it was much easier to ask, just in case somebody already knew about this. Btw, now the oscillation is in stereo... For the sudden shutdown, that should be more complicated, someone had that with two pc-s at the same time, and it didn't seem PSU related, anyway, I don't know how that ended.

***

I have a lot of close friends doing programming, some of them moved to Canada.

Electronics and programming go well together, the people that build processors, chipsets, boards, they're engineers... Anyway, microcontrollers is the field where the 'actual' side of engineering comes in touch with programming, I think you'll enjoy that.

Cheers,

merry

Jan 15, 2003, 06:55 AM	#1
merry gargouille Join Date: Jun 2002 Location: sector ZZ9 Plural Z Alpha Posts: 962 Rep Power: 0	Power-off audio oscillation I use ABit's ST-6, onboard sound. When I turn the rig off, after something like 15-30 minutes, there's a small 'thump' in the speakers and... In the begining there was a continuous tone in the KHz range, not very loud. For a couple of days it has turned into a very low frequency oscillation, audible thumps 1s apart. Anybody else experienced this? __________________ There is a war between the ones who say there is a war and the ones who say there isn't. ~~Leonard Cohen Last edited by merry; Jan 15, 2003 at 08:42 AM.

Jan 17, 2003, 10:42 PM	#2
DcibeL DriverHeaven Junior Member Join Date: Dec 2002 Location: Canada Posts: 43 Rep Power: 0	Sounds to me like you have a bad capacitor on your motherboard that won't discharge. As long as it doesn't make any unwelcome sounds while the computer is on, and the computer is running reliably, I'd say there's not much you can do. If the capacitor is being used for voltage regulation, there is no problems with it not discharging, just as long as it doesn't short out, then your computer will crash. Have a look at your motherboard and tell me if any of the caps have some brown goo on top of them. If there is, this is definately the case. However, if there isn't it doesn't necissarily mean that your caps are in good working condition, it just means they're not leaking dielectric fluid. I could be completely wrong too, I'm just an electronics student, not a bloody rocket scientist. __________________ [D-cibeL]

Jan 20, 2003, 10:22 AM	Thread Starter #3
merry gargouille Join Date: Jun 2002 Location: sector ZZ9 Plural Z Alpha Posts: 962 Rep Power: 0	Thanks, I am an Electronics engineer - nice to meet someone in the business, too many damn poets (sw people) in these hw boards Btw, you know the difference between s/w people and h/w people? Well, the latter wash their hands before they pee... Yes, I also suspect a cap - I'm not a rocket scientist either, neither a computer expert, but it definitely looks like some cap discharging. Although 15-30' is a bit long. And the result is definitely some sort of instability (oscillation), which is weird, I had no idea the audio stages are powered during standby - I thought only the chipset was. Btw, lately the oscillation has turned into a high frequency, now what I hear is a hiss. No significant environment temp variation. My strongest fear was of a PS related problem - there is something else... During a game of Age of Kings (my favourite) the PC sometimes shuts down unexpectedly, and I have to disconnect the PS (switch on the back of the PC) in order to be able to start it again. 3D games work, so I don't believe it's video related. I didn't mention it, as there was a thread a while ago discussing this problem - somebody else had that on two PCs, AMD based - and there was no solution. Thanks for your input, and stay tuned __________________ There is a war between the ones who say there is a war and the ones who say there isn't. ~~Leonard Cohen Last edited by merry; Jan 20, 2003 at 11:47 AM.

Jan 20, 2003, 10:10 PM	#6
DcibeL DriverHeaven Junior Member Join Date: Dec 2002 Location: Canada Posts: 43 Rep Power: 0	I was going to go into computer programming, but the people in that field are just too, ummm...Geeky! As much as I like programming, I would physically explode if I had to work with those kind of people all my life. So my next desiscion was electronics. I'm not taking engineering, but a Technologist course at a trade school. We get to do a lot more building things, and less theory. Now that I've been in school taking this course for while I really think I made the right choice. I absolutely love building electronics, and I won't end up in a cubicle for the rest of my days I've just started taking Digital. We haven't done any work with ASM, but we will in the fall. For now we are programming IC's with CUPL. Pretty fun stuff I'd say! Did you have a look at your PSU Merry? Sounds like the only other thing to check. __________________ [D-cibeL]

Jan 21, 2003, 11:22 AM	Thread Starter #7
merry gargouille Join Date: Jun 2002 Location: sector ZZ9 Plural Z Alpha Posts: 962 Rep Power: 0	Yes, I thought bad thoughts of my PSU... it's still under warranty, so no opening. And I also don't have proper tools at home, to make any measyrements. It's a cheap PSU, but 300W (maybe 350, don't remember). The thing is I should move my posterior and borrow a PSU from somebody, to see what happens - but it was much easier to ask, just in case somebody already knew about this. Btw, now the oscillation is in stereo... For the sudden shutdown, that should be more complicated, someone had that with two pc-s at the same time, and it didn't seem PSU related, anyway, I don't know how that ended. *** I have a lot of close friends doing programming, some of them moved to Canada. Electronics and programming go well together, the people that build processors, chipsets, boards, they're engineers... Anyway, microcontrollers is the field where the 'actual' side of engineering comes in touch with programming, I think you'll enjoy that. Cheers, merry __________________ There is a war between the ones who say there is a war and the ones who say there isn't. ~~Leonard Cohen