Noisy AC adapter?

Does anyone else have a noisy AC adapter? My T410s which I received in January came with a 90W adapter that makes a kind of scratchy buzzing noise. The noise is fairly quiet -- at the office I don't notice it, but when working in a quiet house at night it gets annoying.

Lenovo tech support asked me to take it to a local warranty service provider, where the technician told me it sounded as if something was arcing inside . I just received the replacement today, and it also makes the exact same noise! Both adapters are P/N 42T4426, FRU 42T4427. The serial number on both end in "REV 03."

I wonder if this is something I have to worry about or if they're all like that and I should just ignore it and carry on. Both adapters seem to work fine otherwise, so I'm wondering if this could be something like the infamous CPU whine issue -- annoying but not dangerous.

 

I have a few 90W adapters 42T4426. No buzzing detected/heard so far. Maybe you have SUPER POWER hearing?

That would be very frightening if used at night while sleeping, or any other place unattended. If a tech said it was a arching sound inside, I think there would be a 3rd power supply coming to my door.

 

OK, that kills my theory that they all do this. I'll be calling Lenovo again tomorrow and I think I'll also ask for a different PN in case its just the REV 03 ones that make this noise.

Thanks for your help.

 

My 65 watt makes no noise. Try asking for 65 watt.

 

if it makes a lot of noise, then it should be replaceable under warranty.

 

Thanks graycolor, but my T410s has Optimus which is supposed to use the 90W adapter. I know the 65W would work for normal usage though, after listening to my 90W adapter the technician at the warranty place tried hooking up a 65W adapter to my machine to see if the 65W adapter made any noise (it didn't).

I guess the 65W may not provide enough power if the system is stressed so Lenovo does not offer the 65W for machines with discrete/Optimus graphics.

EDIT: Hi lead_org, actually it was just replaced under warranty. The thing is that the replacement makes exactly the same kind of noise as the original. Not a lot of noise, but it definitely makes noise. I'm sure Lenovo will replace it again, but if they're just going to send me another buzzy adapter I don't really want a stack of these things.

I was hoping someone else with a REV 03 42T4426 would chime in. This is my 9th laptop (2nd Thinkpad) and none of the adapters on the previous machines made any noise at all.

 

Follow up: I called Lenovo tech support back today. The rep put me on hold while he went to check something. When he came back he told me he had checked three 90W adapters and ALL of them made the same noise as mine. He told me that the noise is caused by a relay inside and that all adapters will make some noise, but the smaller adapters make less noise and have thicker casing so their noise is less noticeable.

As long as its not going to burn my house down I guess I can live with it. I am disappointed with Lenovo's electrical engineering capabilities though -- I have a Gateway P7805u-FX at home with a 130W adapter which makes no noticeable noise and yet Lenovo cannot make a quiet 90W adapter.

 

I have a 65w and a 90w (to power the Advance Dock Series 3) and only the 90W makes noise. I don't hear it unless i hold it up to my ear but i was gonna replace it anyways. Just keep forgetting to call . I've had other 90w AC adapters (Advanced Mini Dock for T60-T400 series) and that made no noise. I gave it away when i sold the dock ofcourse andthen bought the new series with new adapter and got the noise now.