Macbook Late 2009 Polycarbonate Unibody Power Button Pinout (Tip)

Discussion in 'MacBook' started by velocityg4, Jun 24, 2010.

  1. velocityg4 macrumors 68040


    Dec 19, 2004
    I could not find through Google what pin out worked the on switch for the Macbook. It seemed unreasonable to buy a new top case just to find out the Motherboard was at fault. So finding a method to turn on a Macbook without the power button was needed.

    I determined this by tearing apart the top case (the owner gave me the go ahead as the computer would have been thrown out otherwise). First of all the framework under the keyboard is glued on. After much frustration I found a hammer and chisel worked best:D. After prying off the framework I removed all keys and protective layers until left with the circuit sheet for the keyboard and power button.

    The circuit layers were then peeled apart. Picking at an edge with a fingernail will peel back enough to get a grip. You can then pull with some force as the plastic is fairly tough, take some care working the internal edges as the sheet is full of holes which are potential tear points. With the layers peeled apart I was then able to trace the circuit path quite easily.

    Once I determined the on button locations I completed the circuit with a very fine wire (I just used one of the speaker wire). The Macbook booted so I knew for certain that it was a bad topcase. Though once the frame was pried off I saw corrosion and when tracing the circuit I found the break I just wanted to see if the crossing the pins would work as with ATX boards.

    Anyways I am posting this so that hopefully anyone in else performing a search trying to find the power pins will have a guide to look at. By the way the board can be completely removed then connect the LCD, a keyboard, mouse, power and SATA drive then boot. If so inclined you likely could permanently affix a power switch and mount this in a case to use as a desktop. Though I did not test an external screen and the battery would need to be connected or the CPU speed drops (at least it does on older Macbooks).

    Macbook Pin out.jpg

    Just connect pin 5 to 29 of the Keyboard Ribbon Connector as shown in the picture. From what I can tell connecting the wrong pins causes no damage. Which makes sense since keyboard presses connect the various pins together.

    This is only tested on the Late 2009 Polycarbonate Unibody Macbook. I would assume this works on other Unibodies with the same keyboard connector. But do not know. Anyone with other Macbooks or Macbook Pro please chime in if you have to try this and it does or does not work. If not please find the correct pin out if you are in the situation of not knowing if the power button or Motherboard is bad. Given how well the keyboard is sealed if the Macbook works for quite a while after a liquid spill then suddenly dies there is a good chance for corrosion of the keyboard.
  2. shalcrow macrumors newbie

    Jul 19, 2010
    Excellent! Thanks for this information.

    I tried your instructions however I couldnt get it to turn on.

    I have the same problem with the power button. After I completely disassembled the macbook, I poured a tiny amount of metho in the power switch. After it dried, I reassessmbled it completely, and when I pressed the power button, I noticed the fan started to spin, but the machine did not start up. I then plugged in the power, and thought this might help, but it doesnt power up, and the fan doesnt even attempt to spin now.

    I checked for power with a multimeter on the battery connection next to the keyboard connection shown in your picture above, and I am (!) getting a reading with the power supply connected, and I am also getting a lower (3.41) reading when checking pins 5 & 29 as shown in your picture above.
    So, if I am still getting power to the motherboard (aka logicboard these days) I'd like to think the mothboard can still function some what.

    I connected pins 5 & 29 with a snipet of our stereo's FM antenna cable, however it didn't turn on. I also tried resetting the SMC with this pin conx. bypass but no sucess.

    What are your thoughts? Shall I deconstruct the top shell? Can you provide some steps (if you remember) so I dont completely wreck the case (irony I know). Or do you know of another technique - or website that actually stock this top case? (it is the same model as you mention)

  3. J&JPolangin macrumors 68030

    Jul 5, 2008
    Thule GL @ the TOW
    ...isn't it still under applecare or did the owner trash the mac somehow?
  4. velocityg4 thread starter macrumors 68040


    Dec 19, 2004
    Sorry I did not respond before. As the search function does not order results by user name correctly anymore I have no way of knowing if one of my threads gets replied to after a couple of days. The MR search function use to order by date of most recent post to a thread now it only does by the searched users latest post in the threads rather than the most recent post by anyone in the thread.

    I assume you resolved this by now. But if you have not try booting with one RAM stick in then switch with the other. If it still does not it is likely dead.

    If still nothing look over the board with a magnifying glass under good lighting and see if there are any burst capacitors or scorch marks as a possible visible failure. Burst capacitors can at least be replaced.

    Owner's son spilled beer on it so the warranty was voided.
  5. andrewwynn, Nov 22, 2010
    Last edited: Dec 6, 2010

    andrewwynn macrumors newbie

    Oct 30, 2009
    Also works for MacBook Pro (unibody)

    while i'm waiting for my replacement kbd to float its way over here (usa) from China, i was hard-core determined to get some work done since i JUST installed a 500GB hybrid drive (boots either win7 OR snow leopard in less than 35 seconds!).

    Anyhow, i had a bad 'milkccident' months ago, and had fixed the keyboard by taking it all the way apart, and on the top row, separated the two films of plastic making the key switches to get in with a swab of alcohol.

    The milk was nowhere NEAR my computer FYI, a bad chance occurrence with a tangled cord pulled it down off a shelf that was over 2 feet away!

    So, got it all back together and working great (one minor goof; i forgot to clean the milk off the face of the backlight LEDs so that acted like a diffuser and made the keyboard brighter near the center but otherwise working perfectly).

    Until a couple days ago when I was working at a clients, set up a long copy and went to run an errand for an hour. I got home and there was a puddle of water *everywhere* including likely 4-5 oz went into the keyboard, but was in there long enough it killed the keyboard this time.

    i found replacements new for about $50-60 on dhgate but while waiting i wanted to get my win7 running and all my data off the two drives it was by necessity split onto moved onto my new muuuuch faster muuuch bigger drive.

    bolstered by finally finding THIS very thread, with the last post about the MacBook and crossing some fingers the pinout would be the same so i didn't have to so through the same sleuth work. THANK you vg4!

    So other than confirming this works for the macbook pro unibody 2008 late, I have a much easier way to touch the pins, at least for a temporary use:

    1. Cut the ribbon cable about 1/2" long
    2. Peel off the TOP protective layer
    3. trim the cable leaving pin 5 and pin 29 long
    4. Use a pointy tweezer to connect the traces to start the computer

    Since i rarely ever shut off my computer, I set an auto-start of 10am in case i accidentally shut down or lose power, and i left the bottom panel screwless since i'll be putting the new keyboard in in a few days.

    I had a crash in winxp and apparently forgot to ALSO set the reboot on power failure (or it didn't count because i closed the lid so it thought i shut down) so i had to do the tweezer start a second time; very painless: flip the battery lever, take off the bottom, tweeze the two traces, broing.

    I will also add that the first time i did it, i first measured voltage on all the pins and noticed that pin4 and pin5 both have 3.33 v but that it only booted going from 5 to 29 not 4 to 29.

    The FIRST time i did it i actually used a tiny piece of 30ga wire and touched the pins inside the connector, the SECOND time using the snip of ribbon cable and a pointy pointy tweezer was 1/10th the effort; total breeze!

    unibody-macbook-pro power-button broken jump-start 15.4 top-case keyboard spill milk beer water.

    (a couple keywords to help a future googler).

    here's a picture: the near side of picture is motherboard, the far side is battery.



    ps: on re-assembly after cleaning out the milk, the backlight didn't work properly (brighter in the center); on the second repair, i noticed that when the milk spilled in, it made a tiny puddle in front of each of the 6 LEDs that backlight the keyboard, diffusing the light so it didn't go as far; make sure you clean the LED lenses if you have a spill that you are cleaning up; especially since the backlight assembly will survive and isn't part of the keyboard assembly.
  6. velocityg4 thread starter macrumors 68040


    Dec 19, 2004
    That's good to know it also works on the 08 MBP. That tweezer method does sound easier.
  7. andrewwynn macrumors newbie

    Oct 30, 2009
    emPHAsis on the 'ER'. Great to see the OP hit the thread after my post so i know credit made it back to the source!

    I left all the screws out of the case bottom while waiting for the replacement keyboard. GOOD FAST CHEAP pick any two. found a good cheap source but whew it's taking a while.

    I can't remember if i mentioned it but once i take the ribbon 'snippet' out when i put in the new keyboard i'm going to make a 'startup key' out of that ribbon cable snippet with pin 5 and 29 shorted or even better yet ; with a tiny tiny pushbutton i can just leave in there for when working on MBP in the future.


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