MacBook Pro Boot Problems

Discussion in 'MacBook Pro' started by davg, May 15, 2015.

  1. davg, May 15, 2015
    Last edited: May 15, 2015

    davg macrumors member

    Joined:
    Feb 25, 2015
    #1
    I have a Macbook Pro Mid 2012 2.5 GHz core i5 running mountain lion that had soda spilled on the key board I have no idea how much or for how long When I try to boot it shows the apple logo and shuts down If I continually hold the shift or the control key it will boot one to safe boot the other normal boot. I can perform some functions but when I release the key it will proceed to shut down. I stripped the thing down cleaned the mother board with Isopropyl and replaced the key board and backlite new but the symptoms are the same. Any help on this would be greatly appreciated I have searched inside this forum but drawing a blank. Apple Hardware Test shows 4SNS/1/40000000;VCOC-3.196???
     
  2. Kissmyne macrumors 6502

    Kissmyne

    Joined:
    Apr 21, 2015
    #2
    It looks like you have a failure with one of the system sensors either not being able to detect voltage, or your voltage is not being regulated properly(voltage regulator on mobo). Soda is the worst due to how corrosive most sodas are... this likely will be involving component replacement, and I am thinking logic board(mobo).
     
  3. davg thread starter macrumors member

    Joined:
    Feb 25, 2015
    #3
    Appreciate your response I have not seen a lot of info on this problem on the net. Was hoping for something more diy fix?? Voltage regulators are kinda small on that board?? Is there somewhere one can get info on these codes Apple seen to keep them a mystery??
     
  4. Kissmyne macrumors 6502

    Kissmyne

    Joined:
    Apr 21, 2015
    #4
    After further research it appears to be a code for the CPU Voltage Sensor being out of range at the package. The reason it boots is because it is defaulting to boot voltage when it first starts, but as soon as the proc is entering a different power state, since it is unable to regulate itself properly due to lack of sensor info it shuts down. This can be CPU but most of the time it will be a fried VRM

    Here is a site that general explains AHT's http://www.macissues.com/2014/03/21/how-to-run-and-interpret-apples-hardware-tests-on-your-mac/
     
  5. davg thread starter macrumors member

    Joined:
    Feb 25, 2015
    #5
    Thanks ever so much Kissmyne appreciate the link. Interesting?? So a fried VRM is a reason to replace the logic board?? Replacing a voltage regulator is not for the faint of heart?? Is it even possible to replace a fried VRM on these boards??
     
  6. T5BRICK macrumors 604

    T5BRICK

    Joined:
    Aug 3, 2006
    Location:
    Oregon
    #6
    Do you have the equipment or experience to rework small surface mount parts?

    Also, you'll have to keep in mind that liquid damage can cause all sorts of problems that you can't see immediately. I'd suggest having the logic board replaced, along with anything else that came in contact with any liquid.
     
  7. davg thread starter macrumors member

    Joined:
    Feb 25, 2015
    #7
    I have done some work on the logic board on lcd monitors and recapped several desktop computers but nothing this small Replacing the logic board is the last option since I have nothing to lose if this board is already garbage? Finding a schematic for the board may be the biggest challenge??
     
  8. T5BRICK macrumors 604

    T5BRICK

    Joined:
    Aug 3, 2006
    Location:
    Oregon
    #8
    I'm sure schematics are out there somewhere, but I'm not sure where you'd find them.
     
  9. davg thread starter macrumors member

    Joined:
    Feb 25, 2015
    #9
    Hopping someone can point me in the right direction??
     
  10. davg, May 22, 2015
    Last edited: May 24, 2015

    davg thread starter macrumors member

    Joined:
    Feb 25, 2015
    #10
    I have had some success in this repair. I actually removed the logic board again gave it a though cleaning with Isopropyl a toothbrush and air, allowed it to dry for a couple of days and reinstalled it!! now here is the interesting part--- once installed I started connecting the components one at a time (as suggested in here) I connected the video cable powered up and voloi it booted, connected the keyboard no boot disconnected again and tried connecting the other components dvd, hard drive etc and it booted. re-connected the keyboard and no boot?? Plugged in the soda soaked keyboard and it booted?? It is still working with that old keyboard attached but with limited functionality? I even tried several times re-connecting the new keyboard but no go?? What are the possibilities of buying a faulty "NEW" keyboard off Ebay?? Now I have to buy another keyboard but afraid of getting the same result?? I 'm in Canada, anyone know a reputable dealer where to buy.
    Even though this mbp seems to be working fine when I run the Apple Hardware Test I still get the same 4SNS/1/40000000;VCOC-3.196 error ???
     
  11. davg thread starter macrumors member

    Joined:
    Feb 25, 2015
    #11
    Was wondering if someone could show me how to troubleshoot this error on the schematic. My knowledge of tracing a fault on a schematic is limited but I do have a schematic and I do know the problem is with a voltage sensor to the cpu or the sensor is reading a wrong voltage to the cpu?? This laptop is working but it is running slow and while on the battery it will shut down instead of waking up from sleep mode I know there are some great technical people on here any help would be greatly appreciated. Thanks in advance.
     

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