Erratic Trackpad problem?

Discussion in 'MacBook Pro' started by Zelcro, Nov 25, 2012.

  1. Zelcro macrumors newbie

    Sep 14, 2012
    I'm not sure if this belongs here, but I could do with some help.
    I recently bought a 13" 2011 Macbook Pro and I have a problem with the trackpad. Whenever it's plugged in and charging the trackpad doesn't respond properly and the mouse jumps around all over the place, when it's running on the battery it's absolutely fine.

    I've looked into it and found that if I rest my hand on the macbook whilst using the trackpad, it works fine, I assume this is a problem with grounding?

    I tried plugging it in at my friends house and there was no problem?

    Any help is appreciated, thanks
  2. macpluslaptop, Nov 25, 2012
    Last edited: Nov 25, 2012

    macpluslaptop macrumors 6502

    Jun 5, 2007
    I had that problem with my 2010 MBP, using both a Magic Trackpad and the MBP trackpad, and called Applecare. I seem to remember that we narrowed it down to a Bluetooth issue. Once I reset Bluetooth it was fine. That wouldn't seem to explain the non-bluetooth MBP trackpad, but who knows...

    Anyway, I think if you search the Apple support forums you'll find similar instances.
  3. Zelcro thread starter macrumors newbie

    Sep 14, 2012
    Thanks for the reply
    I've looked around but I can't seem to find any problems the same as mine
  4. Merlijnus, Dec 30, 2013
    Last edited: Dec 30, 2013

    Merlijnus macrumors newbie

    Oct 29, 2013
    Hi Zelcro

    Did you ever find a solution to this issue? I've just started to experience it and so far this is the only place I found where this problem is mentioned.

    I believe I have narrowed it down to a faulty power supply unit, in my case a 60W magsafe unit A1344, but I'd value confirmation from anyone else with a similar problem.


  5. Brian Y macrumors 68040

    Oct 21, 2012
    It's a grounding issue - i.e. something is causing static build up in the trackpad.

    If you're using the short magsafe plug, try using the longer (grounded) one.
  6. Merlijnus macrumors newbie

    Oct 29, 2013
    While I agree it's something to do with grounding, making good contact between my body and the body of the MBP solves the problem, I'm pretty sure in my case it's a faulty power supply. Using the same power lead and computer, an older power supply (A1184, similar rating) does not exhibit the same problem. My conclusion was, therefore, that the power supply isolation (between mains input and low voltage output) was degraded.

    In my case the erratic cursor movement problem occurred suddenly in two locations where the machine is normally used and has worked without problems for nine months. It's possible that there was a grounding problem in both these locations but it seems less likely than a faulty power supply.

    I routinely use my other MBP unearthed, using a two pin plug, without problems.

  7. jdelgado macrumors regular

    Oct 25, 2009
    I had a similar problem with the trackpad; cursor jumped, clicked, and selected stuff by itself.
    Repairing permissions solved the problem, at least for the time being. I have no idea why this worked.
    Regarding the grounding issue, my problem happened either if I was on battery or charging.
  8. rich285 macrumors newbie

    Oct 8, 2013
    Trackpad Erratic Operation

    Seems like the problem is related to having a number of open windows, which heats up the battery resulting in the trackpad not working. After MBP cools off then the trackpad works again.
  9. jdelgado macrumors regular

    Oct 25, 2009
    I experienced the problem with a cool MBP. The MBP was off and it happened just after startup.
    As I mentioned above, it looks like there are multiple versions on what causes the problem, and similar number of fixes. I guess one has to try several of them, and be happy if one works for your case.
  10. middi macrumors newbie

    Jun 26, 2010
    I have just fixed my problem, if it doesn't happen when you unplug your MacBook, it's most likely and earthing / grounding problem. The small plug doesn't include earthing (even in the U.K where this is prominent). However, the long one does.

    I have yet to test my small plug but with the extension cable, I was having this problem. The fix is this.

    The round stud that you slide your plug or extension cable over is your earth. It's likely that this isn't making good enough contact with the contacts in the extension cable. I took a bit of metal foil (Oreo wrapper if you're interested), folded it up and pushed it in the cutout in the extension cable. you only need a little bit and now my MacBook is perfect again.
  11. brdeveloper macrumors 68020


    Apr 21, 2010
    Just got a chinese Apple charger and this is happening with my White Macbook.
    It shows the same serial number (0x00947f53) as other reportedly fake chargers.
  12. imhereareyou macrumors regular


    Aug 28, 2013
    Looks like it was covered, sounds like a grounding issue. Something is not screwed in properly or something has worn away and exposing metal on a wire.
  13. gez80 macrumors newbie

    Apr 16, 2018
    I have the same issue with my power supply, cheap asian knock off (with poor grounding). Couple of ways to fix this:

    1. Buy an official apple charger
    2. Earth laptop by placing your other hand on the laptop near the trackpad
    3. Plug a USB cable into one of the spare USB ports and allow it to lay on the table to earth the laptop


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