Intermittent vibration on Macbook Air when connected to power supply

hey bluemercury

many thanks ^_^

i have little knowledge and understanding about voltage/current supply to appliances. i too, thought about your arguement and in a way my theory would not make any sense as if it was drawing more than 2.5A at the adapter head, it should flow the fuse. however, the slight differences in fuse ratings made me think perhaps it's being terminated to the MBA body, give me that electric shock i experienced.

still, i will share my findings when i get the replacement fuse later today 🙂

sweejin - excellent detective work on the original changing of the plug / extension cable - thanks again.

The fuse issue is a red herrin though; I don't think it matters whether there are different levels, as long as the fuse is sufficient for the flow of electricity required by the device (and if not, the fuse would just break). 2.5 amps is the lowest common denominator, so we can assume that this is a sufficient current max for the MacBook Air.

I worked out what the issue was today. All along the unit has not been earthing, as I suspected. What had thrown me before is that the internal connector for both the slide on plug and connector is just a two pin connection. So no room for an earth, right? But if you look up in the actual tounge and groove slider, the slide on basic plug is just plastic, but the extension has a metal insert. This is turn will be earthed, and hence we don't get a problem when using the exstension cable. With the slide on plug, the excessive flow of electricity that must be occuring has no earth to connect back at the socket level, and thus flows through the unibody itself, giving us shocks!

All it needs is a modification of the slide on socket (confusingly, there is a metal earth pin on at least the UK version, but it can't be wired), or better still Apple should have jolly well acknowledge this problem and produce a revised slider model. What they've done may pass legal standards, but it certainly doesn't live up to their projection of their supposed high standards.

So I'm taking this up with my local Apple repair centre, and will let you know how I get on. Thanks so much for your original input, and I hope my further discovery helps others get this sorted once and for all. Apple must be aware of this problem!!

Cheers,

Bluemercury

hmm.... yeah, i went to take a look at your observations, and perhaps that would be the better explanation. as surprisingly, i opened to change the fuse and saw it actually WAS a 3A fuse inserted. so perhaps, it wsa a red herring.

i asked around and at least those who purchased a MacBook/Air/Pro from 2010 till now have experienced this issue, and was assured from the Apple store that it's normal. any previous manufactured model prior to that year seems not exhibit the same problem.

lemme know how you get on. at least, if Apple doesn't come back with a solution, good to know the AC extension cord solved the problem in the meantime.

sweejin

Sweejin, thank you for your inputs. The "shocks" Iif you might call it that or "vibrations" was getting on my nerves. It was travelling down by body to the heels of my feet when my palms rested on the MBA (2011). Once I went with the extension cord, the problem was gone. It's definitely some earthing issue. And YES, apple should FIX his and offer to all customers a free replacement of the 3 socket adapter.

It's not a fuse issue, as mine was rated at 3A when I sought to replace it. So maybe the 3 socket adpater might not be grounded at att.

Just to let you know the final outcome - Apple admit to the problem, but are doing nothing about it.

My local [Apple Authorised] repair shop said they knew nothing about the issue, and to contact Apple directly. Going this final step wasn't wonderfully easy, although I eventually found a contact number after going through a pointless ticket opening process on the Apple site (pointless, because at the end it just told me to call them, and the support team had no record of the raised request I'd filled in their ticketing system - nice one Apple!).

The representitive I dealt with was honest, and having spoken to a colleague he agreed this was a problem in all MacBook Airs (and probably other Unibody MacBooks), including the latest 2011 model. He said only some people are sensitive enough to feel the sensation, which I can accept as some others couldn't sense what I could. However, he confirmed that Apple are doing nothing about it, and the general view is that you have to use the extension lead.

I asked where I could register a complaint, and he directed me to http://www.apple.com/feedback/ I strongly recommend that everyone who experiences this problem goes to this site, and registers a complaint. Apple don't think this issue is a big deal, but it reflects poor quality and a lack of consideration, which flies in the face of Apple's supposedly high quality products. I also suspect though may not realise (or are ignoring) the scale of the problem.

So what's the solution? Either use the long lead that's earthed, or find a patent part slider plug. Even Apple hinted at the latter, although I have yet to find one on eBay that is confirmed to do the job (with a wired earth). If I ever do, I will post back here 🙂

Good luck to you all, and thanks again to sweejin for his initial observation on the extension.

Its great that I found this thread. Here is my story:

I have two 2011 MacBook Pro units and have always used the extended 3 plug cord. In New York, I have never felt this electrical discharge. Now I am in Italy and I do feel it from both units. Its irritating and I worry about health issues the long term exposure can cause. I got used to it and I work 8 hours a day, which most of them I just deal with it.

What surprises me is that I am using the extended cord you guys have pointed out is grounded and fixes the issue. I wonder if it is an issue with the electrical outlets in the house. I will try at another house and post back.

Hey, bkuberek.

You've mentioned you've used it in New York - were your units bought in the UK, or abroad in the USA? If it is the latter, it is possible that the extension is not earthed either - I've never seen the USA extension, so wouldn't know. Apple have demonstrated with their slider plug that they will put a third metal pin on, implying there is an earth, but then they don't actually wire it up.

If you look in the inside of the groove on your extension lead (the bit that slides on the corner of the power supply), you should see some metal tucked in the very top. If it's just plastic on there, there lies the problem.

Also, in Italy you may not have earthed power sockets, as that has often been the way in Europe. They do have a plug design that supports earthing, but like America I don't believe it's compulsory to have an earth on sockets (traditionally saying it is unecessary because of creating double insulation; a theory not working so well now laptops are being carved in conductive metal!). In the UK it is compulsory to earth sockets, or certainly has been evident everywhere I've ever lived or worked.....

Good luck 🙂

The US has 120VAC, and Europe has 240VAC. The adapter places one/half of the AC input voltage on the case. In NYC, you'd have 60VAC, probably too low to feel. In Europe, you'd have 120VAC, which everyone feels. All countries have various international safety agencies. In Europe, there are several, one of which is the IEC. One of the IEC regulations reads that the computer will operate properly without the grounding pin. Since the current leakage is well within the international safety limits, it is considered to be operating normally.

It does have the metal piece. But something just happen. I am getting the same electrical discharge even when I am not plugged in. In other words, the computer is on battery and I am getting zapped. I am not wearing shoes so I am ground. Any thoughts?

bkuberek, does the electrical discharge happen when it's fully charged? that has happened to me a few times just after my MBA has a full charge

Thanks for having taken the time to research and solve the problem.

I've only had my mba 13" for a few days and have only randomly notices the buzzing/vibration, on what is otherwise an awesome piece of kit.

I have moved over to the longer power lead as pointed out and the problem has disappeared as expected.

why would apple be so tight about connecting up the earth, especially if they knew people were having a problem... There should be a petition about this....

Has anyone found a 3rd party 3 ping plug slider attachement that we might be able to make use of with the requisite metal part?

This would be great information if anyone out there could share.

Many thanks

S

Hey safety_uk.

I've searched high and low - with the promise that should I ever find a properly earthed slider plug, I'll post back here. Sadly, that means I haven't. Everything I find on the market is unearthed. A few on eBay couldn't be advised either way, but probably were knock-offs of the same unearthed design.

I read a blog the other day about how Apple spend $250,000 per machine, for a piece of equipment that lasers holes invisible to the naked eye, for their LEDs to defract and shine though. This is how the webcam on the MacBook Air (and probably other models) appears to 'light up' the adjacent metal surface when in use.

A company that, whilst spending so much for a feature that isn't mandatory (but admitedly cool), but doesn't bother to spend a few pennies earthing their plugs, shows a completely contradictory and incongrous angle on design. Apple would argue that the electrical flow we suffer is within legal limits, which it is, but this completely flies against the principals of a firm that has built its success on extreme levels of quality engineering and design. It makes no sense to me, and is damaging their reputation.

I will happily sign any pertition, and in the meantime, I definitely recommend you user the www.apple.com/feedback form to lodge your complaint. And Apple if you're reading, every MacBook Air I resell I have to make my clients aware of this shortcoming. For some, it understandably puts them off, and they are choosing to buy the competition.....

thanks for the feedbacks blue,

i've already written in and left a feedback/complaint in their website. hopefully, more people get to do the same and they will rectify the problem down the road.

Hey Bluemercury

I've left feedback as you suggested. I don't believe anything will come of it.

Coming from someone who has just left the world of M$ to Mac I find this kind of problem rather worrying...

In my mind anything regarding electrics or physical safety being left to 'legal tolerances' is just a no no. I'm quite surprised by Apple's attitude with this.

Had i known before I moved over I would have genuinely had to take a second look at my decision but its a little late for that now :'(

Regardless, I hope we can find an alternative plug from a another vendor or maybe some smart chinese knock-off company will fix this for us once they've read about our problems!

Maybe I'll approach a manufacturer and see what can be done - I'll keep you all posted!

Thanks again

S

No worries - and grateful to all who direct this feedback to Apple. I wouldn't mind betting that this forum is getting thousands of hits, and if anyone reading suffers this problem, complain via www.apple.com/feedback .

I think in the end Apple will [have to] sort it, if nothing else to maintain reputation. Any manufacturer could carry on in this manner within the law, but it just grates on me when I hear people banging on about the extra quality of Apple components, yet they let such a rudimentary issue go on. Their designs are awesome, but some of their engineering doesn't live up to the hype. It will be extremely interesting to see similar Unibody aluminium shell based Ultrabooks coming on to the market (particularly as we go in to 2012 with proposals from Dell rumoured) and whether they have the same issue. Certainly, if they don't this will be a catalyst to make Apple re-think their plug design.

I have still yet to find a patent part slider plug alternative that is earthed, and for now admit defeat and will tolerate using the extension cord permanently.

Cheers to all,

Bluemercury 🙂