Thinkpads Forum

When I'm on an instant messaging video call, the person on the other end says that there is noise when my charger is plugged in to AC power. There's no noise when the laptop is plugged in to the automobile charger. I was able to make two recordings, one with the charger plugged in where the noise can be heard and one unplugged with no noise. Is this normal? Or does it mean there is something wrong with my charger, sound card or something else? The two clips are below.

Plugged in:

http://members.cox.net/clearanceaccount ... d%20in.mp3

Unplugged:

http://members.cox.net/clearanceaccount/unplugged.mp3


Thanks,

Tony

Sorry, but I can't get either of your links to work. It looks like they are being hosted on your personal cox.net webspace so there may be some access issues.

hopefully the noise is the laptop actually turning on!!! - It would be on my R40!

No, cannot get the links to work so I can't help you here!
Sorry

Ray, I was able to listen to the mp3's. The first one has a low level background 'hum', and the second one is clean. The first thing I'd try is a different power source, then the AC adapter.

Generally speaking: sometimes AC hum can be eliminated by turning the plug over (if both tangs are the same width).

You might be able to eliminate the hum by running a grounding wire from the screw holding the wall outlet plate to some metal point on the computer.

Plugging into a UPS (universal power supply) might solve this issue.

Sounds to me as if there is not enough 'ground' on the power circuit.
Perhaps a loose connector, or dirt inside the connector?
As Harryc suggested, try another outlet.

I get a buzzing noise from my AC adapter; one I can just hear by listening to the adapter brick itself... Strangely, this only makes noise when I am not charging my battery; the buzzing goes away when I plug my battery in.

This issue does not occur on my T60's adapter, which is also 90W but has the third grounding prong. The adapter I got with my T400 does not have the third grounding prong and makes this noise.

Grr. I am probably going to send the buzzing adapter back to Lenovo under warranty.

Thanks, everybody, for the replies here. I had some time to run a few elementary tests (tried a different 65 watt adapter and a 90 watt adapter), and the noise is still there (even with those adapters) albeit to a slightly lesser extent. Something I failed to mention (forgot about it, since I'm usually on wireless) is that the noise is also present even when on battery but only if the CAT5 LAN cable from the router (on AC power, too, naturally) is plugged in to the ThinkPad. Also, the noise is never there if I use the less "sensitive" Bluetooth headset. I'll have to do some tests at someone else's house, but, for now, I'll have to conclude that I simply have a case of "dirty" power here at home and that the wired headset is extremely sensitive. A UPS would probably help, but I'll live with it for now.

Much appreciated,

Tony

GomJabbar wrote:Generally speaking: sometimes AC hum can be eliminated by turning the plug over (if both tangs are the same width).

You might be able to eliminate the hum by running a grounding wire from the screw holding the wall outlet plate to some metal point on the computer.

Plugging into a UPS (universal power supply) might solve this issue.

Hi everyone. I thought I would reanimate the thread because it appears the most relevant of what is available online to what is happening to my thinkpad x200. As described above, turning the plug over at one angle stops the electricity burning sound. I am fairly sure the problems occurred first when I moved in to the presently rented flat. I was convinced the problem was related to faulty sockets all over the place because the bulbs get broken like nowhere before (I am in UK).

I have just noticed that the sound does not occur when the battery is full. This strange angle dependant thing - any idea how this can be explained?

Thanks
T