Getting electrical tingling/shock sensation in 2012 13" non-retina Macbook, when connected to USB, electrical powered external HDD!

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Level 1

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Getting electrical tingling/shock sensation in 2012 13" non-retina Macbook, when connected to USB, electrical powered external HDD!

Hi all,

I've bought a Macbook Pro 13" Mid 2012. When I connected an External HDD with independent power supply, I felt a weird electrical buzz/tingling sensation in my hand while having on top of the laptop, specially in the left side of it.

I made some tests, and noticed I could diminish the electrical buzz by either:

- Connecting the laptop to its charger;

- Putting my righ hand in the laptop as well. Imagine your left hand on it, feeling the buzz, add the right hand, buzz stops, and so on;

My first reaction was to ask a friend that owns a similar 2011 Macbook Pro 13" to test this behaviour. It did not happen, everything was normal!

I went to the store and reported the issue. We made the same test with other Macbook Pros non-retina (13" and 15") and it happened exactly the same!

I had the Macbook for 3 days only, so I decided to ask for a refund, since though other macbook pros 13" mid 2012 have the same behaviour. The store guy, after seeing this, also told me that his iPad feels the same sometimes, and that he had to buy a cover to remove the tingling sensation in his hand while holding it.

I can't consider this to be normal. Apple needs to fix this! What the ****?!

Regarding the macbook, could it be USB related? The 2011 Macbook pro has USB2.0 and this new one has USB3.0.

Anybody experiencing the same? Can you test with your own Macbooks?

Thanks

João

As footnote, I did the same test using a Macbook Air, and did not get the same weird result.

MacBook Pro, OS X Mountain Lion (10.8.2), Mid 2012 with USB3.0

Posted on Nov 30, 2012 5:04 AM

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Answer 1

xtedx

Level 1

88 points

Dec 17, 2012 8:49 PM in response to joaofribeiro

Hi, I have this tingling sensation since macbook pro 2007, when charging without the grounded cable (3 prongs adaptor head)

Since then I have searched online for a solution but nothing available.

Now with mackbook air 2012 it is still the same (tested in many different countries, like australia, europe, japan, india)

The problem is not there when charging with the grounded and long cable.

I have asked around friends who use aluminium case of macbooks and they all could feel this buzz.

I wonder why Apple doesn't make the short adapter head with 3 prongs , it simply has no metal connector inside and therefore there is no grounding of the laptop.

It is much lighter to travel with the short adapter head, but from now I think I just have to bring the long cable.

This is not a problem when using older plastic case macbooks.

please apple.. help to resolve this.

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Answer 2

Courcoul

Level 6

18,588 points

Dec 17, 2012 9:01 PM in response to xtedx

Till this issue is resolved for good and since both blades on the accursed "duck's head" adapter are the same width (unpolarized), have you tried flipping the power brick over half a turn on the outlet?

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Answer 3

xtedx

Level 1

88 points

Dec 18, 2012 5:07 PM in response to Courcoul

The power plug I used is Australian and it cannot be reversed, (not without an adapter) and the problem is still there.

like in europe or japan, i noticed that the buzzing feeling is greater when polarity is reversed.

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Answer 4

sanjampet

Level 5

7,982 points

Dec 18, 2012 7:50 PM in response to xtedx

You need to use the 3 prong adapter the drain voltage flows thru you and not the ground to drain to earth, if the data(firewire is wired correctly there will be a drain cable that flows to the pin 1 ground to sent it to earth. If this is not configured properly it will flow thru the user. Bonding the ground to the neutral with a bridging diode can greatly help eliminate the back flow of voltage to the user. Bottom line use the 3 prong power cable, plugged into a properly designed powered strip for the un grounded EHD to drain thru the neutral. But what do I know?

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Answer 5

Mar 11, 2013 4:40 AM in response to joaofribeiro

I get this problem really bad too... I seem to get it all the time and so i use a mouse as much as I can! Ive got a horrible feeling it must be quite bad for you as our bodies are run on electrical impulses afterall... Would love some kind of solution as I do love my mac!

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