Intermittent vibration on Macbook Air when connected to power supply

Hello all 🙂

I haven't posted on this for a while - but thought I would share one recent experience.

Having established using the extension cord to earth the unit stops the problem, I have tolerated this for the last few months. I did look to see if a slider plug with an earth was available, but sadly it was not. I promised to post back if so, but have not found one (certainly not from Apple, nor a third party).

A client of mine recently bought the 2011 model MacBook Air. Interestingly, there is no longer a slider plug included at all. Now you just get the extension lead (or now standard lead), and nothing more. This is based on what they showed me anyway - there was no slider plug in the box.

So it would seem that instead of Apple improving the slider plug with an earth, they have just discontinued it being included. I guess this 'solves' the problem for new buyers, but wasn't quite what I hoped for when I encouraged people to raise a complaint! Seeing as this post has approaching 8000 hits, I guess they got lots of responses, and this was their resolution. Not a great result :S

Now you just get the extension lead (or now standard lead), and nothing more. This is based on what they showed me anyway - there was no slider plug in the box.

In the 2011 model I purchased recently, the package included the magsafe adapter, 2-prong connector and 3 pin cable - as has been supplied with every Mac laptop I have bought over several years. Thus, whatever Apple's response (or lack of) they have not appear to have modified the adapter or cabling supplied.

That is in the US, at least.

Sorry, I knew I'd omit that crucial detail! I'm in the UK, where the slider plug has always been 3 pinned, but with the metal 'earth' pin not actually earthed (just there for cosmetics). This is what my clients didn't get - just the extension lead, although it is entirely possible that Apple quality control left it out accidentally, as opposed to having a new policy to no longer include it. I wouldn't know for sure without speaking to someone else in the UK that has bought a very recent MBA 2011 model... As soon as I do I'll update 🙂

Sounds like in the US the slider continues. I know in the US that are lot of power outlets have historically been un-earthed 2 prong only, so this would make sense (I guess only the extension lead gives you the US third pin for earth?). In England, we've had three pinned earth plugs as a legal standard for well beyond my lifetime (I'm 30) which makes the matter all the more bizarre - they have a metal earth pin on the slider plug, but it just isn't wired up!

You should be able to check what is included by checking the 'What's in the box' list in the MBA specs on the Apple store UK site - it looks the same as it has previously (and matches the US version) but of course it's possible they haven't changed it yet.

In the US, there are relatively few unearthed sockets, though it was previously very common. There are many two-pin power chords however, which is not common beyond shavers etc in the UK since the 15amp (round pin) standard gave way to 13amp (square pin) standard in the early 60s.

In my time buying Apple laptops in the US (2002 was my first here) the mains adapters have always had two-pin connectors. Some of the earlier models (such as the one with my 2002 TiBook) also had two-pin mains leads, but all the ones I've had since have had three-pin mains leads.

I'd much prefer that a conductive-cased laptop carried a viable earth, specifically to help control static charge accumulation, and I don't think there's any reason Apple provide a two-pin connector rather than a three-pin, except that it would determine that the magsafe adapter be necessarily larger. I believe that's why they supply the three-pin cable instead. To my mind it's a question of form over function, which is disappointing - though nothing new. However, if the lack of earth is problematic for some users - at it clearly is - at least there's the option to use the grounded cable instad.

Reversing the 2-prong plug made no difference; I still feel the vibration. Funny thing though... no matter which way the 2-prong plug is plugged in, the vibration can only be felt when my finger is dry. When I moisten my finger, no vibration is felt.

Another thing. When I'm talking on the telephone (wired, not wireless) holding the handset, and then touch the MacBook Air, a hum can be heard on the telephone, both by me, and by the party at the other end.

Using the 3-prong extension cord eliminates the vibration problem, and the telephone hum problem.

BB

I just purchased my late 2011 MacBook Pro 13 inch. I'm having the same problem when I plug my power Mac power/charging cord into a recepticle without using a surge protector. If I use a surge protector the issue is non-existent.

The feeling is a low level tingling feeling that hurts over time. By the way if I unplug my power cord with my left hand while my right hand is touching the top of my MacBook, the low level electric current ceases immediately. Then if I plug the cord right back into the recepticle the low level electric current tingling feeling returns immediately.

I owned a MacBook white prior to this MacBook Pro and never had any issue of this sort.

Well, I am in Bangalore and bought my MBA 11 few months back. Recently for first time I was using it while plugged in. I was irritated to feel the weired vibration when grounded ( not wearing slipers ).

Typically, I checked the grounding and it was alright.

To my mind, it may be happpening due to Metal body and some fault in designing of electric sockets.

After reading the threads above, I was relieved that: am not a lonely sole and in not in danger of loosing my MBA.

Please share your thoughts friends.

"I owned a MacBook white prior to this MacBook Pro and never had any issue of this sort."

That's because the plastic case was not electrically conductive.

"I don't think there's any reason Apple provide a two-pin connector rather than a three-pin, except that it would determine that the magsafe adapter be necessarily larger."

There is a reason. The computer meets dozens of international safety and radiated emissions standards. An IEC standard requires that the computer operates using a 2-prong, ungrounded AC power cord. The simple solution is to use the 3-prong AC power cable plugged into a PROPERLY-GROUNDED AC outlet.

"The feeling is a low level tingling feeling that hurts over time."

Specifically, the "tingling feeling" is 1/2 of the AC line voltage at a very low current. The voltage is placed on the computer chassis to control the level of the emitted radiations of an ungrounded computer. All computer companies use the same scheme.

"but with the metal 'earth' pin not actually earthed"

However, the metallic "knob" onto which the "duckhead slides IS grounded. Accordingly, if you use a 3-prong US AC outlet duckhead, and plug that into a UK AC prong adapter (with a metal ground pin), the computer will be properly grounded and the tingling sensation will disappear.

To prove that this phenomena is not related to Apple, try this: unplug the power adapter, and allow your computer to run on the battery. Plug an ungrounded printer into the USB port. You will feel the tingling sensation, because printer manufacturers use the same scheme as do the computer manufacturers.

This happens on my MacBook pro and my iPad 2 when charging. Also if I rub my fingers down the wall when I'm touching one of the devices while charging I get the same sensation.

Carl,

Will this stray current affect the Macbook circuits? My worry is the stray current may jump from one conductive part of the motherboard to another creating a spark and cause damage.

I have a sony vaio earlier and the monitor had stopped working, when the service center had opened it up, they told me that the motherboard had some indications of sparks causing some burn traces.

I understand that this meets the IEC guidelines, but is there any documentation that it wont hurt the laptops hardware with the low voltage?

Unfortunately in India even the power cord sold by apple is two pin. While India is known for its grounding issues.

Regards

Keegan

my problem solved..!! thank you sweejin...!!

I just purchased a 2012 MacBook Air in the US and now I am in Bahrain (which uses the UK style plug) and I have noticed the vibration feeling too. I didn't pack the 3 prong extension cable with me though, I'm using the 2 prong power block, and I only feel it when it's plugged in. I think I'm going to go to an authorized Apple dealer tomorrow and see if I can purchased the 3 prong extension cable and hopefully it will alleviate the annoying feeling.

"Will this stray current affect the Macbook circuits?"

Nope. The current isn't "stray", it's purposely put onto the computer chassis. There's no danger to either you or your product.

Static electricity (a much higher level DC voltage) is a different story, and it can damage electronics.

you are very welcomed 🙂

Hi all,

I am traveling in Europe and did not bring the grounded cable for my US purchased Macbook air. The vibration used to occur when plugged in in the United states but didnt bother me so much because I rarely used the computer plugged in. But now it is my primary computer and it is very uncomfortable.

I am in France and then will be in the Czech republic. Does anyone know how I can resolve this problem? If I go to an Apple store here will they have a cable they can sell me that will ground it? and will it work in Prague or should I wait until I get there?

anyone have any suggestions? thanks so much

Katarina