Audio Problems When Charging Acer Laptop

Acer Extensa 5430-5720 15.4" notebook -...
February 22, 2012 at 11:35:31
Specs: Windows 7 Pro, AMD QL-65/3 Gb
I posted this question in General Hardware last week and got no hits, so I thought I'd try it here.

In addition, the problem has recurred, so I assume it's going to be a on-going problem.

I have a new-to-me Acer Extensa 5430 laptop.

I was listening to a local radio station on-line and didn't realize that the charger was unplugged. The laptop was connected to my sound system via the headphone jack.

When the system shut down due to the battery level, I plugged in the charger and the system began to resume Windows. As it was resuming, I began to hear that old fashioned "modem noise". You know, the beeps and clicks of data moving through the pipes.

This "data noise" continued to be there behind the music even after the browser resumed. I unplugged the charger and the noise went away. I plugged the charger back in and the noise came back. BTW...the transformer for the charger was as far away form the laptop as the cord would allow.

I restarted Windows, but it was still there, but only when the charger was plugged in.

It wasn't until I performed a complete Shutdown and then powered back on that the noise went away.

The latest time that this happened, I caught the low battery warning before the system shutdown and plugged in the charger. As soon as I did, the "data noise" started up. One again I had to perform a complete shutdown, with the charger plugged in, in order to eliminate the noise.

What do you think is causing this issue?

Thanks!

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#1
February 22, 2012 at 13:54:28
Maybe new to you is old broken to someone else?

Noise could be any number of issues. From simple issues to possibly hazardous issues.

Can you return it?

A Pit Bull is like a gun you can pet. And there is no safety on it.


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#2
February 22, 2012 at 18:34:35
I could probably contact the seller...30 days parts & labor warranty.

I may do that, although I've got this thing all set up the way I want and I'd hate to have to redo it all again.

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#3
February 23, 2012 at 11:30:44
The Problem you are suffering is called a feedback loop, and it is caused by the power lead not earthing properly. This does not mean the power lead is faulty, it is "The norm" from laptops. I have the same issue in my recording studio.
The best fix is to buy a feedback loop resistor, for a few quid on ebay. its like a clip that goes over the powercord and filters out the grounding loop.
There is another that involved wrapping a wire around a usb plug, and grounding it.....BUT, I would not try that, as my old boss did it, and I can't remember how, so don't take my wire wrap as advice (Could help if you wanted to search), but I would go with buying a feedback loop resistor.

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Related Solutions

#4
February 23, 2012 at 11:31:49
An edit to my previous post..... It's called a "Ground loop resistor" sorry.

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#5
February 23, 2012 at 12:54:53
In the US almost all if not all power supplies are three prong plugs. If you have a ground issue it is a serious safely issue with your homes electrical system. The brick is a double insulated device and really shouldn't need a third ground. It is a transformer that is in-grounded tied to rectifier and control circuits. There is nothing that a less than master electrician could do to fix it. It is a sealed unit and no one should mess with it. There is no safe way to fix it but you need to find out if the unit or your home is bad. Like I say, even a faulty ground should not cause this issue.

Just return it.

A Pit Bull is like a gun you can pet. And there is no safety on it.


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#6
February 23, 2012 at 14:14:05
Unless you have applied unauthorised grounding (probably in two places) then ground loops should not be an issue with double insulated devices.

Always pop back and let us know the outcome - thanks


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#7
February 23, 2012 at 18:14:43
I'll see if I can get it to happen again and then try a different receptacle. Both times it's happened, it's happened when the charger was plugged into the same power strip.

However, this same circuit has been powering my sound system components, my flat screen, DVD, cable box, etc. for years with no problems. In fact. it's a dedicated circuit I ran just for my sound system.

We'll see what happens.

Thanks!

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#8
February 24, 2012 at 11:15:54
As I posted before, the problem isn't a fault with the equipment. I tried to simplify my post to ease confusuin, but here goes... The ground loop is normally cause because 2 components (mixer and amp for eg:) are earthed to the same exit point, could be a 4 way plug, but mainly the same "ring circuit". It's the "difference" in voltage these units use (aka mixer sucks less juice than the amp), that creates a leak, or the ground loop. the difference could be just 1hz, but it's enough to cause the hum or buzz. I agree, if the issue is larger, then the leaked voltage could damage equipment, but it sounds to me like a simple issue of your equipment using the same ring circuit. This link: http://blueguitar.org/new/articles/... is a pdf doc which explains in extreeeeeeme detail, all about the issue of ground loops. It's so common in audio setups with laptops it's almost as famous as the windows 7 audio lag that us musicians fix by using asio4all.
Set aside an hour and some coffee if you read that document lol.
And good luck my friend, let us know if you fix it. (I still stand by getting an isolator, which to correct my earlier post clips over the audio cables, not the power cable).

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#9
February 24, 2012 at 11:24:00
Oh btw, If you wish to try it... borrow someones "usb soundcard", and I'm willing to bet it dissapears. Then you could get one of them instead. the usb port grounds with the laptop which eliminates the loop.
And that noise you can hear?? That is the ground loop amplifying the movements of your laptops hard drive head zipping back and forth and transferring data lol.
I actually found it fascinating for about 20 seconds when I knew what it was, but then it annoyed me so I fixed it hehe.

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#10
February 24, 2012 at 13:03:08
I suspected it was the hard drive noise...it changed when accessing programs, the control panel, etc.

re: "I still stand by getting an isolator, which to correct my earlier post clips over the audio cables, not the power cable"

But the noise is there even when I unplug the cable from the headphone jack to the amp. It then comes through the laptop speakers. It'll be hard to clip anything over the tiny little wires that go to the laptop speakers. ;-)

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#11
February 24, 2012 at 15:34:25
lol, i agree. you cant stop it if you listen to your laptop speakers. i'm fraid you can't do much to the insides of a laptop. but if you go external to an amp or hi fi. the resistor, or usb soundcard is the way to fix it i'm afraid.

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#12
February 27, 2012 at 08:54:09
Thanks for all that info.

OK, this sounds like a bad idea, but I'm going to throw it out there:

What would happen if I used a 3-prong adaptor (one without a ground prong) when charging the laptop while its attached to the receiver via the head phone jack?

If the laptop wasn't grounded via the charger, would the noise still be present?

Would the ground in the audio cable from the headphone jack to the receiver still provide a path for the noise?

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#13
February 27, 2012 at 09:25:36
Firstly I should warn that removing grounding could create a safety issue. Without examining the equipment in detail and making electrical tests is is not possible to comment further on that important aspect.

If it is double insulated then most likely there is no ground connection to the plug pin anyway, so it would make no difference.

If you intend to try this idea anyway and the plug is moulded to the cable, it would be best to create a temporary two wire extension cable, rather than make a permanent modification. Dismantle this cable after use.

Whatever, it takes grounding in two places to create a loop, so it is unlikely to help unless there is a second grounding point somewhere.

Always pop back and let us know the outcome - thanks


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#14
February 28, 2012 at 11:31:52
re: "If it is double insulated then most likely there is no ground connection to the plug pin anyway, so it would make no difference."

I'm not sure what you are referring to here. I can't imagine a molded 3 prong plug with no ground connection to the plug pin. Who would build/sell such a thing?

The laptop charger has a 3 prong plug with a cord that plugs into a transformer block. From the transformer block there is a cord with a jack that plugs into a jack on the back of the laptop.

re: "If you intend to try this idea anyway and the plug is moulded to the lead, it would be best to create a temporary two wire extension lead, rather than make a permanent modification."

When I mentioned "a 3-prong adaptor (one without a ground prong)" I meant one of these:

http://static.www.odcdn.com/picture...

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#15
February 28, 2012 at 12:18:37
Hmm, I'm from the UK so things will be a bit different in practice, although the principles are be the same. By "moulded plugs" I mean that you cannot access any of the connections because the plugs are moulded onto the cable, like this:
http://yunhuan.en.alibaba.com/produ...

I was assuming (rightly or wrongly) that in the states, like us, some devices which are double insulated might have a 3 prong plug moulded onto the cable but the ground prong is not actually wired up. Here, all of our plugs and wall sockests are 3 pin. [Our wall sockets have a safety shutter over the live and neutral which is opened by the ground prong on the plug].

As long as the adaptor you choose doesn't electrically extend the ground connection it will achieve what you are trying to prove, with the safety proviso I gave in #13. It will still be able to charge.

Always pop back and let us know the outcome - thanks


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#16
March 2, 2012 at 09:37:39
I can't say that I've ever known a device to have a three pronged plug where the ground plug was not wired. My gut tells me that the NEC (National Electrical Code) would not allow it.

I know who to ask...so I'm going to do just that.

I'll be back...

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#17
March 2, 2012 at 11:04:16
It is not easy to tell whether a device with a three pronged moulded plug has the ground conductor connected or not, without doing an end to end electrical test. This would most likely entail taking the device to pieces, which I would obviously not recommend.

As I said, I am a bit shaky about USA practices, despite being a qualified electrical engineer in the UK. Google here biases my searches to UK so I have been unable, so far, to learn very much more about the USA situation than I already knew.

Let's put it this way, if you were fitting a plug yourself and there were only two wires, you would presumably fit a two prong plug. Electrically you could equally well use a three prong plug instead and not connect anything to the ground prong terminal. There is nothing unsafe about this and it is quite normal in the UK despite us using 230V - where there are only two wires then they are connected to the live and neutral terminals. If there is some regulation that precludes this arrangement in the USA, then I can only imagine it is to stop some idiot connecting one of these two wires to the ground prong. Maybe your contact will be able to give us a more tangible reason.

------------------------------------------------------

Whatever, this detailed discussion, although interesting, is purely academic. The last line of my #15 says about all you need to know for this temporary excercise.

Always pop back and let us know the outcome - thanks


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#18
March 7, 2012 at 15:23:58
Just in case you come back, although I have not unearthed any USA info about the elctrical situation we were discussing, I did find this:
http://en.wikipedia.org/wiki/Cheate...

This seems to be the device in your link in #14 and its use appears to be depricated because of safety issues. This does not surprise me because if there are three wires then this implies that it is necessary to ground the appropriate wire.

It is quite different to what we were discussing which was, more or less, whether it is necessary to make a ground connection to a device that only had two wires in the first place.

Always pop back and let us know the outcome - thanks


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#19
March 11, 2012 at 12:15:25
I found this on ebay which looks to me like it will solve your issue. I found it using your isolation transformer link, and finding an equal solution. I hope you get the link before it ends. Also, I am going to get some in time, because they seem exactly what will work for me. I did notice, that it's the exact solution I mentioned earlier except its built into the cable.

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#20
March 11, 2012 at 12:16:14
Duuuh, It would help if I posted the link haha...... http://www.ebay.co.uk/itm/2-Channel...

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