Failure modes in sound cards

I've had a couple older pc's that I used for music servers. They were both hooked up to an 80's-vintage Onkyo amp.

In both cases, the onboard sound cards worked for a long time, but then just stopped working. The pc's still work, just not the sound function.

Since I'm getting tired of configuring new old pc's for the task, I'm wondering if there's a common failure issue I can look for.

Any suggestions?

Reply to
Randy Day
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[snip]

Just a couple of boat-anchor win98 boxes. Load them up with Winamp, a bunch of mp3s and internet radio links, and voila - music to get you through the day.

And, in case I gave the wrong impression, they didn't get hooked up and blow immediately; they both worked for months on end, and then ... didn't.

So either lightning got them, or there's a mismatch that's slowly cooking something inside. I guess my question boils down to: Do soundcard outputs have a blocking capacitor? the schematic of the Onkyo has them on the inputs, but if they're leaky, that's a problem.

As a general rule, are soundcard outputs dc-blocked, or direct-drive?

Reply to
Randy Day

There are coupling capacitors on the inputs and outputs. Are these computers online, or dedicate with no outside connections?

--
Anyone wanting to run for any political office in the US should have to 
have a DD214, and a honorable discharge.
Reply to
Michael A. Terrell
[snip]

Online, for internet radio.

Reply to
Randy Day

Are you sure the receiver is not at fault? Onkyo's aren't the most reliable things, now or back then either.

I'm assuming you are using an analog output from the sound card - do the other analog inputs work OK? Regular stereo or using surround sound fields?

Mark Z.

Reply to
Mark Zacharias

Does it have antivirus, a firewall and malware protection?

--
Anyone wanting to run for any political office in the US should have to 
have a DD214, and a honorable discharge.
Reply to
Michael A. Terrell
[snip]

I hadn't considered malware, but I suppose it's possible. Is there malware that turns off the sound card?

Reply to
Randy Day

It can mess up almost anything. The sound may not work, simply because the malware is using too many resources.

--
Anyone wanting to run for any political office in the US should have to 
have a DD214, and a honorable discharge.
Reply to
Michael A. Terrell

Most audio and TV devices are not grounded so a dangerous voltage develops in their grounds. Now consider what happens if the ground in your audio cab le fails open, a dangerous voltage will be applied.to the audio inputs. It is common for audio jacks to make unreliable contacts, so this could be the cause of your problem. To.stop this I would wire a reliable connection bet ween PC and amplifier grounds.

Reply to
Jeroni Paul
*Most audio and TV devices are not grounded so a dangerous voltage develops in their *grounds. Now consider what happens if the ground in your audio cable fails open, a *dangerous voltage will be applied.to the audio inputs. It is common for audio jacks to make *unreliable contacts, so this could be the cause of your problem. To.stop this I would wire a *reliable connection between PC and amplifier grounds.

Horseshit. It would make a loud hum noise - nothing worse.

I see this sort of thing all the time.

Mark Z.

Reply to
Mark Zacharias

If it's an older machine - maybe the bios battery failed or otherwise the audio options maybe got reset in the bios?

Turned off your sound card in favor of an on-board device? Or vice-versa? Turned OFF an on-board device if that's what the OP was using?

Has OP checked sound and audio devices under Device Manager? Driver good?

Mark Z.

Reply to
Mark Zacharias
[snip]

good?

Another set of excellent possibillities. I will definitely check them out.

This group rocks!!!

Reply to
Randy Day

Normally I would agree with this - until it happened to me. It DID make a l oud hum and then the sound died - permanently. FWIW it was a Realtek onboar d sound chip. Device manager said it was operating correctly. Yeah, the DIG ITAL parts worked but the analog was toast.

Reply to
stratus46

Wrong, this is very risky to do and I have seen lots of stuff damaged that way. Common to damage the inputs on TV scart sockets, TV outputs in video c ards, audio inputs and outputs, etc.

I particularly hate RCA connectors, most of them have the center terminal l onger than the ground so it is the first to contact when plugged. Very dang erous situation if there is no other link joining the grounds of both devic es. Audio jacks and F plugs suffer the same problem. Other connectors are s omewhat better where ground usually contacts first like USB, DVI, legacy PC ports (serial, parallel, VGA) and Scart. But do not rely on that, connecto r design if far from perfect in this regard.

To avoid nasty surprises I always plug sensitive cables with both devices u nplugged from mains and have the precaution to momentarily touch grounds fi rst to discarge any static.

Reply to
Jeroni Paul

I'm with you on not plugging stuff in when powered. It's only common sense.

I stand by my statements however. Been repairing audio for more than 30 years, and have factory training from majors such as Sony, Yamaha, Pioneer, NEC, Hitachi, Denon-Marantz, and others.

It's even OK to lift the chassis ground from a desktop computer box to eliminate a ground loop. Unless the unit's power supply primary short happen to short to chassis, there is no shock hazard. That is why the primary circuit is isolated.

We have these types of discussions on the groups all the time. One recent one had to do with the third wire ground on oscilloscopes. Yes, you should leave them intact and not defeat them, but no harm will arise from bypassing - they are there more for manufacturers liability issues, where possibly hundreds of thousands or even millions of these things are going to be in use in all kinds of situations the manufacturer cannot control, often by people with uncertain levels of training or experience.

Mark Z.

Reply to
Mark Zacharias

While ground loop noise is fixed disconnecting grounds *one* ground *must* remain connected so both chassis are at the same potential. In this case bo th devices are properly grounded and no loud hum occurs.

But if one or both devices are not properly grounded and you do not connect audio ground you will get a loud hum and you are asking for trouble. The u ngrounded device is being grounded through audio circuits. This is not OK a nd may result in damage and you was not right when you said that was safe t o do.

Of course the danger level depends on the equipment used. Some people likes to connect the PC to a music box that in turn is connected to a FM aerial together with some TV sets and other equipment all of them ungrounded. In t his scenario many devices are grounded through the audio cable, a real dang er if it goes open or it is plugged/unplugged.

Reply to
Jeroni Paul

Denon-Marantz ? I thought Sony bought Marantz.

???

Reply to
jurb6006

One thing to consider is that PCs are usually equipped with three prong cor ds which means they have an Earth ground. this means that all the line leak age of any connected equipment flows throught the commons, or grounds on an ything like an audio cable, anything.

I had to deal with a wierd ground loop problem on a commercial projector be cause it was properly grounded and so was thre cable coming in. Turns out t he guy had two ground rods installed and there apparently was a ground grad ient. the guy is an electrician actually ! I had to build him an isolator. It came out of an old TV that had a hot chassis, all I had to do was attach the correct connector.

That happened because the projector was three prong, but can happen to anyt hing else like that, if they do not go to the same ground.

In other words, your ground is not my ground.

Reply to
jurb6006

Any great stories of weird training or tips and tricks from any of these companies?

I came across a operator/service manual for a machine that said buff and shine the shiny mechanical parts with car polish or wax, and that the idea came from customers, it seems like a good idea and so that's now suggested as standard operating procedure for everybody.

Reply to
Cydrome Leader

Ground issues with parallel cables running to printers in other rooms was always interesting. There's nothing like sparks when pluggin in a centronics connector.

10base 2 networks had this issue too with everything all over the place being grounded to each other.
Reply to
Cydrome Leader

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