Powerbook G4... Earthed through the aluminum case?

Discussion in 'PowerPC Macs' started by Xandros, Oct 16, 2013.

  1. Xandros macrumors regular

    Joined:
    Sep 19, 2010
    #1
    When I first got this Powerbook (G4 15" 1.6Ghz DLSD "Hi res") the first thing I noticed when it was charging the battery was the "feel" of the case. While resting my palms on the two spots either side of the track pad for instance, I can feel the case is electrified, it's only a tiny background charge but it's definitely there, most likely a charge. When the adapter was plugged in if I ran my hand over any bare metal part it feels "alive" (only way I describe it).

    It's at its worse when the lid is shut and the computer is either in sleep mode or turned off. If I run my fingers over the lid my fingers literally feel like they're buzzing. If I happen to be using the laptop with bare skin touching the edges (like my stomach, since admittedly I tend to use the thing a lot in bed) I often get sharp stabbing pains, like someone is sticking me with a needle in the area where my skin is touching the case, though this only seems to happen intermittently and only on areas of my body with very sensitive skin, like my forearms on my stomach.

    Thinking it could be a fault with the adapter I eventually got a new one (not because of this issue but because the original one got broken). And it does the same thing. It didn't do this at all however when the power adapter wasn't plugged in and it was only running off the battery.

    This can't be right... I will mention that I've had two batteries for this laptop the time I've owned it and neither of them lasted much more than a year before they packed up. The first one started to discharge randomly after only a few months of use and got worse and worse until I eventually got round to replacing it a few years back with another original Apple battery shortly before they stopped making them. But the second one only worked for a year before it stopped charging completely.

    Maybe it's related to the batteries. Maybe not. Either way, it just doesn't feel right...
     
  2. Nameci macrumors 68000

    Nameci

    Joined:
    Oct 29, 2010
    Location:
    The Philippines...
    #2
    The charger/powerbrick comes with a standard 3-prong plug. The round plug is for ground. If your utility had a third earth/ground wire on your outlet, it will drain that neutral to ground current.

    If your powerbrick uses the two-prong "duck-head" the earth/ground will float and instead drain via the chassis through your body.
     
  3. eyoungren macrumors P6

    eyoungren

    Joined:
    Aug 31, 2011
    Location:
    Phoenix • 85037
    #3
    I have two 17" AlBooks and my wife has the 12" AlBook. My son has a 15" TiBook. Based on all of that, that does not sound normal.

    I usually run my PowerBooks off the power adapter because the batteries are all gone. But I only feel something of what you indicate when the Mac is working. But that's coming from the vibrations of the hard drive.

    I'm in the habit of touching a metal surface before picking up my PowerBooks just to discharge electricity. That's what I thought your thread was going to be about, but apparently not.

    My guess right now would be a problem with your DC-In board. That's the board that handles the transfer of power from your adapter to the internal components.

    Is your powerjack loose? Where you plug in the adapter. Can you wiggle it around a bit or is it fairly tight?

    If it's loose or a case of having the adapter in the right place in order to power the laptop it may be that because the board is bad it's leaking power. I don't know if that's something that could or does happen, but it's my first guess anyway.

    Let us know.
     
  4. Mnowell69 macrumors regular

    Mnowell69

    Joined:
    Jul 4, 2013
    Location:
    Bedford, UK
    #4
    Out here in Italy we have a 2 prong system and all my aluminium macs are alive, quite a weird feeling.
     
  5. wobegong Guest

    Joined:
    May 29, 2012
    #5
    Ditto here in the Philippines, two prong only - that 'live' feeling on the case - Back home in the UK (three prong system) no 'live' feeling on the case at all, with the same machine. - This is with a newish MBP.
     
  6. Swampus macrumors 6502

    Swampus

    Joined:
    Jun 20, 2013
    Location:
    Winterfell
    #6
    The same thing can happen with bad ground in the US, but the lower voltage keeps it below the perception threshold of most.

    OP, it does give me pause that you used the phrase "sharp stabbing pains". That's a little beyond what is normally experienced with this sort of problem. Some even describe it as a pleasant sensation. At worst, a minor annoyance. Maybe best to err on the side of caution and take it to an electrician to measure what is actually being put to ground through the case.
     
  7. Nermal Moderator

    Nermal

    Staff Member

    Joined:
    Dec 7, 2002
    Location:
    New Zealand
    #7
    My US-import 2006 MBP was the same way. Haven't noticed it with my NZ 2011, which only has a two-pin plug.
     
  8. wobegong Guest

    Joined:
    May 29, 2012
    #8
    Yes agree, for me it's a sort of 'trembling' sensation - very light - Stabbing pains don't sound good at all ;)
     
  9. mayuka macrumors 6502a

    mayuka

    Joined:
    Feb 15, 2009
    #9
    I have the same problem with my Powerbook and Macbook Air. It is much less anoying as you described it, though.
     
  10. Xandros thread starter macrumors regular

    Joined:
    Sep 19, 2010
    #10
    I apologise I should have mentioned I'm in the UK, with the three prong system. However it did get me wondering for those stating you get the same with the two prong systems... I pulled the plug and had a look at it and sure enough... The earth prong is made of plastic, so evidently though it's a three prong plug it's the same as a two prong plug in terms of functionality, thusly doesn't have an Earth...

    Well that explains why I'm being electrified when using the Mac. :eek:
     
  11. Nameci macrumors 68000

    Nameci

    Joined:
    Oct 29, 2010
    Location:
    The Philippines...
    #11
    Are you in the islands?

    ----------

    Of course all grounds/earth should be connected to the body if it is metal and should be connected to the third-prong on the electrical plug.

    In the US i use both the "duck-head" two-prong and the three-prong extension cord. I got the sensation when the duck-head is in use but not with the extension cord.

    Neutral to ground would sometimes be just around 9volts. But still be very careful. If you isolate your feet from the floor, were you still be able to experience it? The PB has rubber feet and even if the table is metal, the PB case will still be isolated from the earth/ground.
     
  12. Beavix macrumors 6502a

    Beavix

    Joined:
    Dec 1, 2010
    Location:
    Romania
    #12
    Same here on my PowerBook, and on all aluminum Macs I had/have, including my G5 when connected to a socket without grounding.

    To get rid of the electrical charge I use an extension cord with grounding, see the attached photo.
     

    Attached Files:

  13. Swampus, Oct 17, 2013
    Last edited: Oct 17, 2013

    Swampus macrumors 6502

    Swampus

    Joined:
    Jun 20, 2013
    Location:
    Winterfell
    #13
    With a two prong connection, you get a virtual ground (or functional earth). I've never taken apart an Apple power brick, but it's usually done with a couple of special capacitors that split the line voltage. It's the cheapest way to do it and it's permitted globally for double insulated products. In the United States, the worst case scenario would be 50 to 55 volts from case to ground at about 0.1mA. Well below the perception level of virtually everyone. For you, it could be double since fixed resistance would mean that current is proportional to voltage, but it still shouldn't cause sharp stabbing pains.

    When made part of a circuit, Ohm's Law applies to the human body just like everything else. And there resistance can vary from person to person, but if you were so hypersensitive, it seems like you would already have known it and would already have experienced problems with other things. That's why I suggest that a licensed electrical professional might be in order. It would be easy enough to measure voltage from case to ground, but a lot harder to dial in on the amperage with a basic home multi-meter. A licensed professional will either have the right equipment or know how to substitute known resistor values to do the math. It's unlikely that s/he will be able to diagnose the specific problem with your Powerbook, but you can learn whether or not it is dangerous. Although my imagination is unable to produce a malfunction that would cause a laptop to become deadly, a quick Google search suggests that it does happen.
     
  14. Swampus macrumors 6502

    Swampus

    Joined:
    Jun 20, 2013
    Location:
    Winterfell
    #14
    Aye. Do be careful. Until you know what is going on, at least try to avoid making your heart part of a ground loop. Hand to hand is just as bad as hand to foot. The electricity that comes into our homes is already well suited to disrupt nerve communication between the brain and heart. Across the body, you're getting into the danger zone at only about 10mA.
     
  15. gavinstubbs09 macrumors 65816

    gavinstubbs09

    Joined:
    Feb 17, 2013
    Location:
    NorCal boonies ~~~by Reno sorta
    #15
    I have the mid-2007 carryover PBG4 MacBook Pro 15" and sometimes I will feel like little shocks, and if I have one hand touching the MBP and another to my G5, I can feel a small shock go through my finger to the G5 almost as it's like burning me. Sometimes I feel shock through my elbow.
     
  16. Old Muley macrumors 6502a

    Old Muley

    Joined:
    Jan 6, 2009
    Location:
    Titletown USA
    #16
    So I'm Not Alone

    So others feel this "tickle" when touching stuff too? I've actually got a couple of devices around the house that do this.

    It is obvious when I touch the metal back of my iPod Classic, but only when plugged into my Bose SoundDock and only if the SoundDock is plugged into the charger. Unplugging the charger and the tickle goes away immediately.

    I will also get this tickle from my MacBook Pro or my work HP EliteBook, particularly if I have one palm resting on the chassis of the computer and reach over and touch the metal part of another plugged in device. (This happens at work, or at home, so I know it's not outlet-specific.)

    Nothing I'd ever describe as hurting, but there is definitely something there.
     
  17. Goftrey macrumors 68000

    Goftrey

    Joined:
    May 20, 2011
    Location:
    Wales, UK
    #17
    Another one here too. Same charger as the one pictured above over all of the 5(?) PowerBook's I've owned & all have had that 'alive' buzzing sensation - both here in the UK (which is 3 prong) and abroad in France.

    I also have a Mac Pro & an aluminium keyboard - touching the PowerBook's casing with one finger and the Pro or keyboard with the other gives a serious prick.
     
  18. cyberghoser1 macrumors member

    cyberghoser1

    Joined:
    Nov 18, 2009
    Location:
    Athens, Hellas
    #18
    My Hi-Res G4 Powerbook acts like that too! On battery its fine though.
     
  19. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #19
    It's a secret feature of aluminum enclosure: fingertips electromassage :D
     
  20. bavbavis macrumors newbie

    Joined:
    Aug 4, 2010
    #20
    Use the extension lead

    I am also in the UK and they all do that. If you use the small extension cable with the plug on the end rather than just the small plug for the adaptor then that also has the earth connected and the issue wont be present.
     
  21. Xandros thread starter macrumors regular

    Joined:
    Sep 19, 2010
    #21
    Oh well, thanks all for the input. I've concluded that it's within nominal levels. While the sharp stabbing pains I often experience may suggest it's above normal levels, I do have quite hypersensitive skin of areas of my body so perhaps I am more aware of electric shock than most people.

    Just glad that over the years I haven't ever used the thing totally naked in the literal sense of a "lap top computer". That would have been a bit of a shock, if you'll excuse the pun.
     

Share This Page