T43 electrical noise near Access IBM button

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Ambassador · #1 Post by **Ambassador** » Wed Dec 21, 2005 6:06 am

Hello people,

I have a new T43 (2668-74G) and it makes a kind of electrical noise near the Access IBM button. It could be some interference with the microphone, or something else, don't know... Strange thing is the noise stops for a while when I enable the bluetooth radio.

Does anybody experience the same problem with their T43? Which parts are located near the microphone in the body that could make such an electrical like noise?

I have the latest drivers / BIOS etc. installed.

Thanks for all your help.

aznmikex215 · #2 Post by **aznmikex215** » Wed Dec 21, 2005 10:55 am

i also have this strange electical buzzing noise in the same access IBM/ LAN/ earphone/microphone jack area. Its not terrible loud, the user is probably the only person that cna hear it in absolute silence. just a little annoying and causes paranoia

I also have a brand new T43, latest everything. It has never been dropped or mishandled.

danda821 · #3 Post by **danda821** » Wed Dec 21, 2005 11:01 am

I also find similar problem. Esp. when using the battery wiht maximum performance, the noise when you move mouse or the trackpoint.

Ambassador · #4 Post by **Ambassador** » Wed Dec 21, 2005 11:22 am

Yes that's exacly it. Do you have the same model?

More people with the same problem? Anybody found a solution?

christopher_wolf · #5 Post by **christopher_wolf** » Wed Dec 21, 2005 11:40 am

The rare times it has happened to me, I just just toggle the power schemes in the Power Manager and it goes away. Right now, I am on Battery and using it fine, no noise; not even the fan is on.

danda821 · #6 Post by **danda821** » Wed Dec 21, 2005 11:59 am

The model I have is 2668AJU.

davidspalding · #7 Post by **davidspalding** » Wed Dec 21, 2005 3:09 pm

Doesn't happen on my 2668-75U. From your description, it seems this "electrical buzzing" is emanating from close to the communications daughter card (CDC) ... and if changing the Bluetooth effects it ... maybe this is a problem with the CDC? Not grounded well, or shorting slightly, or just a bum CDC? Maybe if you all can post what model of CDC you've got, a pattern might emerge.... Just a suggestion, mind you.

Serpent · #8 Post by **Serpent** » Tue Dec 27, 2005 9:43 am

Just for information: according to our local IBM services (Moscow, Russia) the mentioned noise is a known problem of T4x/T4xp series (the noise comes from the low-to-high voltage converter of the backlit LCD lamp) and it is covered by IBM guaranty, therefore the converter is exchanged for free.

That's it. Sorry my English, I hope it's still clear.

Ambassador · #9 Post by **Ambassador** » Tue Dec 27, 2005 10:25 am

Thanks Serpent for the comment. This sounds logical indeed. Is the TFT voltage regulator (FL invertor?) located close to the CDC?

Serpent · #10 Post by **Serpent** » Tue Dec 27, 2005 10:41 am

Ambassador, as soon as I'm not sure about the placement of the converter, I've forwarded your question to my friend from IBM service. I've got a new t43 (2668-84G) this week and have just the same problem. The noise comes somewhere near from Access IBM button. Awaiting for the answer from IBM.

Serpent · #11 Post by **Serpent** » Tue Dec 27, 2005 11:34 am

So. They say there are several impulse transformers, all of them placed on the mainboard, including the area close to CDC (where the LCD cable is). These ones work with the TFT backlit lamp and are (or become in a short time) often that noisy. It is caused by a bad filling of the transformers with a compound which is used exactly to avoid this noise. IBM service solve the problem by motherboard exchange.

Besides, in many cases this noise doesn't present permanently. It's connected with different CPU frequinces (for example - different power/frequency schemes when working on battery or on powersouce). Some freqs might come is resonance with the transformers so they become heard. Servicemen suggest to try to change CPU frequency when noise is present to avoid resonance. Still it's just a half measure and motherboard exchange would be a better way to solve the problem.

And at last. Unfortunately, services can't guarantee fluter from the transformers will not appear on the new motherboard with time.

Huh. I hope I made myself clear. ))

xfn · #12 Post by **xfn** » Tue Dec 27, 2005 7:35 pm

Thanks Serpent.

If you ask IBM support (USA) about this kind of noise from a thinkpad system under valid depot warranty, they may quickly send you an EZ serv box to mail the system back to them for hardware diagnosis and/or fix, and tell you this free-service will take 5-7 business days. If you don't like this option, then just throw the box away. Also you may try some local IBM authorized repair centers.
At this stage, I doubt any manufacturer will take this electro-magnetic interference thing very seriously, unless there is some loud noise caused by hardware failure.

Some related links:
http://forum.thinkpads.com/viewtopic.ph ... highlight=
http://forum.thinkpads.com/viewtopic.ph ... highlight=

snRNP · #13 Post by **snRNP** » Wed Dec 28, 2005 2:10 am

danda821 wrote:I also find similar problem. Esp. when using the battery wiht maximum performance, the noise when you move mouse or the trackpoint.

I have the same exact problem that you describe. I found a "fix" for it; however, it will severely decrease the battery life of the thinkpad. I went into the bios, then went to Config>Power>CPU Power Management. I changed the option from Automatic to Disabled. This makes the buzzing go away in all circumstances for me whilst using the computer on battery power. But, as i said before, changing that option to disabled made my battery life suffer by alot.

I, personally, can live with the sound because when I'm on battery I usually use the Max Batt setting because I need my 6-cell to last me through biology, chemistry and english classes, and as such I still use the Automatic setting. If you have a real reason to use max performance whilst using the battery and can't deal with the sound, then my "fix", if u can call it that, "works."

Thinkerer · #14 Post by **Thinkerer** » Wed Dec 28, 2005 6:58 am

See here for discussion and suggested workarouns:

http://thinkwiki.org/wiki/Problem_with_ ... tch_noises

The workarounds are mostly Linux-specific, but some have analogs in Windows. For example, try undervolting with NHC.

Filip · #15 Post by **Filip** » Sun Jan 01, 2006 9:48 am

I experience that always when I have a large transfer over the network (wireless or wired).

mlrtime · #16 Post by **mlrtime** » Mon Jan 02, 2006 7:57 pm

+1

I have this same problem on a 2668-71u. It only happens when running on battery power. Most noticible when using the network.

The first think I think of is a ground loop coming from speakers, but more random.

T43 electrical noise near Access IBM button

T43 electrical noise near Access IBM button

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