Strange feedback into power supply from MBP

Discussion in 'MacBook Pro' started by di1in, Oct 24, 2011.

  1. di1in macrumors regular

    di1in

    Joined:
    Feb 27, 2011
    #1
    => Whenever I plug my MBP into a Inverter & battery based power supply any action done on the MBP brings reactions from the power supply in the form of fluctuations.

    My MBP also has the slight shock effect when I use it while plugged into the mains. I can feel it if the MBP is charging and I drag my finger over the closed lid.

    But the problem that I outlined in the beginning was noticed just a few days ago. When the power goes out, the Inverter + Battery based backup gets activated. If the MBP is plugged in while this happens, any major change in the display - change spaces, open tab, close tab - brings out a significant dimming in the lights around the house. It only dims for as long as the display is changing ( a few ms). The voltage is obviously fluctuating. Why does this occur?
     
  2. Macman45 macrumors demi-god

    Macman45

    Joined:
    Jul 29, 2011
    Location:
    Somewhere Back In The Long Ago
    #2
    Bad Ground


    I think you have a loose ground or earth wire in the Pro itself. I'd get that looked at...Mine doesn't exhibit any of the behaviour you describe here.
     
  3. Matthew Yohe macrumors 68020

    Joined:
    Oct 12, 2006
    #3
    This is normal for a device that's floating its ground. It's double insulated so you're fine.

    So... You're saying that your macbook is connected to some sort of battery backup, and then when you do things on it, lights in the house react? Are they also on the battery backup?

    Are you drawing more current than your battery can deliver?
     
  4. di1in thread starter macrumors regular

    di1in

    Joined:
    Feb 27, 2011
    #4
    Yes, the whole house is connected to the battery backup. I'm not sure if we're drawing more current - usually the inverter flashes overload when there are too many appliances switched ON. We run a couple of TVs, around 8 fluorescent lamps and a couple of ceiling fans without it flashing the Overload warning.

    The flickering occurs only when the Mac is being used like I explained above. I don't know if the other appliances also induce flickering at a higher frequency which might prevent me from noticing them.
     
  5. di1in thread starter macrumors regular

    di1in

    Joined:
    Feb 27, 2011
    #5
    Could someone confirm whether I should avoid using the Mac on this power supply? I don't want a fried Mac, there are no Apple Stores in this state.

    Update:
    I meant a fried macintosh, not a Mcburger
     
  6. Eliz macrumors member

    Joined:
    Feb 2, 2012
    #6
    fluctuating voltages

    The place I live in has fluctuating voltages coming in. Thus, I put up a voltguard and the readings fluctuate from about 180-220 V. Since nothing can be done, can I use my Macbook Pro with this kind of irritating fluctuations.
     
  7. katmeef macrumors 6502

    Joined:
    Jul 20, 2010
    #7
    Is it a pure sine wave or modified sine wave inverter? I have a large ups for my sump pump and it uses a modified sine wave inverter which isn't appropriate for many modern electronic devices unfortunately. I tried my tv on it once and it started making a horrible humming noise...

    http://en.wikipedia.org/wiki/Power_inverter
     
  8. Eliz macrumors member

    Joined:
    Feb 2, 2012
    #8
    no, no. it's just a small "voltguard" that has a voltage reader and a fuse that blows off if there are spikes etc...
     
  9. katmeef macrumors 6502

    Joined:
    Jul 20, 2010
    #9
    Sorry I should have specified, my question was directed at OP :)
     
  10. Eliz macrumors member

    Joined:
    Feb 2, 2012
    #10
    actually, my bad :)
     

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