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Sell me your broken computer

jump start 17 inch unibody

edited January 2012 in General
Hi john,

The MacBook had coffee spilt on it. I only turned it upside down and cleaned it with a rag. I finished a class I was logged on to and put it asleep thinking everything was ok. Got home and it would not power on. I'm just wondering if I can jump start it to rule out logic board issue. The board is different then your YouTube post where you point out the jump points.

Is it true the points are at the keyboard ribbon cable? Is the ribbon cable accessible without tools? Could it be under a small metal cage that is has the nintendo screws. Or is it not possible to jump start these newer unibodys. I don't really have time to do the keyboard replacement but it would be nice to know if it was a total loss.

A little history.. I did replace a key board and LCD screen in a 13 inch white MacBook a few years back for my girlfriend with a friends tool kit. I again have no tools and in a panic last night tried to remove the bottom of the MacBook pro with a knife and when it slipped I managed cut a peace if my thumb off. Boy that last screw. Looks like no stitches but is a cut. I'm lucky to have a thumb as the little pocket knife is vary sharp. Now that I think of it I could care less about the computer. Just looking at my thumb.

Thanks Play safe and do not panic as I did.


  • edited January 2012
    Hi! Sorry to hear about your can get a nice little screwdriver kit at Home Depot or pretty much any hardware store for $10, so I'd really recommend picking one of those up, not only for your own safety, but because you're going to scratch up and devalue the computer by messing around with a knife.

    If you have the early 2009 model, the pads are just to the left of the memory slots, and just to the left of a small pin that is between the two screws at the left end of the memory slots. They are fairly visible, and just left of this pin. If you have the 2010 version (I think this is what you have), it's in the same area, but about another inch further left, just left of a small orange cable, and just right of the screw in the bottom-left corner of the logic board.

    It is recommended to disconnect the keyboard ribbon cable before jumping the board, because depending on the damage, the power button may be stuck in place and prevent jumping from occurring. You can always try it both ways. In the 2009 model, you're looking for an inch-wide ribbon cable very close to the right side of the memory slot, and in the 2010 model, it's under a metal grate in the same place that must be removed first. The cable can be disconnected by releasing the plastic clamp from both sides with a small flathead screwdriver, and then pulling the cable out once it is free.

    Anyway, good luck!
  • gbkgbk
    edited February 2012
    Hi John. Well I have some tools to start this project up again. I am thinking I should take it all apart take off the board and maybe try cooking it in the oven after I buy a keybord on line or just wait...? Is it hard to find a board on for this computer? Say I replace the board and the keyboard is there a chance that something else could have been damaged from the coffee spill?

    Little more history I did not turn the computer off after I spilled the coffee. I turned over the laptop and padded it with a rag and put it to sleep. Came home 6 hours latter and it would not power on.

    Any way you were right looks like I have the 2010 model. I was not able to jump start the computer. I think the board is fried now but maybe I can now find out..... for sure? Would you describe the jump start pads as square, silver, and looking like a drop of solder or are they smaller round things that are also silver with a black dot in the center? To the far left of this stuff is a nintendo screw and above it are black and gray cables. I used a paper clip ( maybe not a good tool) to touch two of the pads but I am concerned the pads might pop off if I mess with them. Does it sound like I am doing this right? Should the laptop be plugged in when I do this because the green light is vary week on the jack? What If the battery is dead? I did get the orange cable disconnected after taking off the grate. If I can not get it jump started, what might I do next? I would like to take a look under the board and see what the liquid damage looks like.

    Thank you
  • edited February 2012
    If the light on the AC adapter is dim, it's most likely not going to power on in that state. You need a solid light on the AC before it will power on. Do you see any corrosion on the board? Look at it with a flashlight and see if you can spot any. You can clean it off with 90% rubbing alcohol and a soft toothbrush. Wait an hour after cleaning, then power on again. Yes, it does make sense to take the board out and clean the other side, especially if you don't see any on the bottom of the board. The dim AC light indicates the board probably has damage somewhere. It may also be on the DC-in (the connector that the AC adapter plugs into). Once you have a solid light, you can then start trying to power it on, and bridge the power-on pads.

    If you're risking them "popping off" then you are applying too much's only necessary to tough them lightly. A paperclip should be fine.

    You should also test the RAM slots by powering on with one slot empty, and then with the other empty.

    It's very likely you fried the board, because after the spill you did not shut it off, which most likely means it got fried. When you have a liquid spill, you should ALWAYS turn it off immediately, clean it up, let it dry, and then try powering on.
  • gbkgbk
    edited March 2012
    Hi John thanks.

    Okay the logic board looks good. After taking it out I found under it a nice even layer of dust. So I am fairly certain that no liquid dripped through the three layers of key board. I cleaned off the dust with a q-tip and alcohol. Not a good idea I should have used an old tooth brush because the q-tip tents to leave some cotton on the components. I will take your advice and retire a tooth brush and do it right before moving on.

    After taking out the 50 small screws of the keyboard. I pulled out the keyboard and on the metal backing of it, I did found what appeared to be a little bit of cracking old liquid that was sticky to the touch. I decided to clean it off. On further examination I found a blemish .... It looks like a fried/ melted spot on the first layer of plastic that has (I'm guessing) inside of it the circuit of the keyboard.

    John do you think that what I found is corrosion and the source of the problem? Maybe I could buy a keyboard for under 100 bucks and have a MacBook Pro again?

    I also took out and cleaned up the dc connector because it was filthy. Other wise every thing is cleaned up. Just not sure what to do next.
  • Honestly, if jumping the board doesn't work, there's not much point in taking apart or replacing the keyboard. The whole point of jumping the board is to remove the keyboard from the equation and see if the board is functional at all. If you can't jump it, then a new keyboard is not going to help. It's like buying a new starter for your car when your engine is fried.

    A better approach, like you mentioned, is to make sure the board is clean and free of corrosion. Dust can short out a board, so it's important to make sure you've cleared it away. Look at the board under a magnifying glass and with a flashlight. When the light on the AC adapter plug is dim, it's usually due to board damage, but to be 100% sure you might want to replace the DC-in. Also, try another AC adapter, and test your RAM slots by leaving one slot empty, and then the other slot empty. Often RAM slots are bad, and if you remove RAM from the offending slot, the computer functions normally.

    But if you try all this and still have a dim light, and the machine won't start, you have a 99.9% chance of a bad board, and a new keyboard is definitely not going to help.

  • Hi thanks ....well im still thinking there might be a chance to get this working again. Ok the dim light could be that I didn't put everthing back togeter correctly, lots of little screwes and cables.I dont see any thing that would indicate the board was fried... would there not be some burnt area on the board someplace if it was fried? Again it looks cleanyou didn't address the melted plastic on the keyboard? I don't see how any liquid could make its way town past the keyboard in this machine because how sealed the keyboard was. Do you have a link to a video on how to jump start the I7.
  • Hi! There are different 17" models, so if you have the last 3 digits of your serial number, I can look up to see where the power-on pads are. A dim light could mean it hasn't been put back together right, but it's also a classic sign of a board with a power issue. A board that looks 100% perfect can be 100% dead -- there isn't necessarily a physical indication. The unibody MacBooks are actually by far the most prone to liquid damage of any Apple laptops made so far...liquid very easily gets down through the keyboard and onto the board. In the past Apple laptops have had metal shielding between the keyboard and board, but not unibodies. It's hard to know what the melted plastic means in terms of trauma to the board, but it's certainly not a good thing -- temperatures hot enough to melt the keys could easily cause the board to have power issues.
  • Um OK I took the computer apart i have to disagree its looks like the keyboard is sealed well 50 screws along with the sealed backlight ... tempeture did not heat up and melt the key... The melted plastic I was referring to is internal... Each key is woven together with a paper thin metal matrix that makes up the keyboard. The damage resembles what a blown fuse would look like. im guessing that its the location of the short within keyboard. I would see other parts with heat damage, some change in texture or discoloration if it were damage as a result of high temperature. BTW what does a water damaged keyboard look like? Other websites have said that unibodys are not prone to liquid damage aside from issues with keyboard. Again its not making sense to me that a board would be dead permanently without oxidation being visible. I have put things back together adequatly only a few screws left over. Your right its an model A2917 serial # c7c are widely available. The battery has to be dead by now. I think replacing the mag safe and keyboard, total cost of $50 is a safe bet for a $3000 machine. I'm starting to think the whole jump starting is kind of out there ...seems better to replace parts as there aren't many. If imgoing to be jump starting it haha ... I might as well be open to cooking the board in the oven... I saw a friend do it to his Xbox and you know it worked. 450 degrees for seven minutes and bam it was done. I was going to put pizza sauce on it but the guy was fast he wanted to game:)
  • edited June 2014
    If you take off the bottom casing and look at the board while it's upside-down, the power-on pads are in the far bottom-left corner, between the screw in the corner and the small sleep sensor ribbon cable. They are vertical. You should disconnect the topcase ribbon cable before trying to jump it.

    A few leftover screws are a few leftover screws too many, and any one of them could account for a dim light. Especially if you've used wrong screws in any location. Go to for a guide in order to make sure you're doing it right.

    I'm not speaking hypothetically -- I deal with thousands of Apple laptops a year, and unbodies by far have the worst record for bad boards and liquid damage, far more than iBooks, PowerBooks, and earlier MacBooks. It's getting to be a big problem for refurbishers, because we have piles of unibody carcasses, and not enough good boards.

    The thing is, if you have a dim light on the AC, a new keyboard/power button is not going to fix that. And the DC-in is only very very rarely part of the problem, unless it has corrosion right on it, so I would not suspect it. By replacing it you're just shooting the messenger. So it's very unlikely anything is going to change with a new DC-in, and especially a new keyboard, as long as you have a dim light. Remember to test the RAM slots by powering on with one empty and then the other empty, because the extremely common issue of a bad slot can cause a dim light.

    If you had a solid green light, which it doesn't sound like you do, then the proper approach would be to jump the board, because buying a keyboard without jumping the board is to take a shot in the dark. Only at that point if you were able to jump the board would buying a new keyboard/power button make any kind of sense. And if you weren't able to jump the board at that point, I'd scrub down the board on both sides with rubbing alcohol, try again, and if it still fails, it's likely a lost cause. Beyond that, it's a matter of having the schematics and also being really good with a soldering iron and a multimeter, and most of the time that kind of effort is just not worth it. I wouldn't call jumping the board "out there"'s pretty much the most basic troubleshooting step you can take with these laptops, and it's critical to knowing whether you're looking at a bad board or a bad keyboard/power button. But like I said, a green light is a prerequisite, because no board will power on with a dim light.

    Liquid damage can be as subtle as to not be visible at all, but more commonly it looks like a dried dusty/milky stain. The board should have a shiny finish, and liquid damage eats away that finish and makes it look dull.

    I always find it more productive to simply pay attention to the symptoms the laptop is presenting rather than try to determine what happened to it, because the symptoms are concrete, and what caused the issue is likely something you'll never know.
  • gbkgbk
    edited June 2014
    we will see... funny " the power-on pads are in the far bottom-left corner, between the screw in the corner and the small sleep sensor ribbon cable. They are vertical. " your description seems far form concrete. again 3000 $ computer all riding on such a description. btw the dc in does have corosion and the board has always looked clean. a lote of people would disagree that you always have a few screws left over. "being really good with a soldering" what about reflowing the board in oven? anyway im thinking of re-flow the dc in and see what happens. thanks for your imput. one more questioin if the keyboad is bad would't that cause a dim light. oh and what does it mean when there is not light on at all?
  • Well, short of being able to show you the power-on pads in person, that description is about the best I can do. If you dig up a copy of the service manual on the Internet, you'll see a nice clear picture of it. Again, jumping a board is a totally basic step, and there's nothing strange or unusual about it. I have no idea why you would be skeptical of that procedure. I jump dozens of boards a day, and it's about as fundamental to the process as jumping a car that won't start. Putting the board in a reflow oven without having even attempted to jump it is completely absurd, and you'll most likely destroy the board, if it's not beyond repair already (which it sounds like it is). Using a reflow oven is a measure of last resort. You can't reflow a DC-in -- you will melt the cables that are attached to it. If you have corrosion on the DC-in, then replace the DC-in, and see if that restores a solid green light. You need a solid green light in order to jump the board.

    No, a bad keyboard has absolutely nothing to do with a dim light on the AC. You can disconnect the keyboard cable on a working MacBook and the light should still be solid green. A dim light usually indicates a power issue. Again, you can't jump a board with a dim light -- you have to have a solid green light first.

    I'm sorry, but the people who would disagree that a few leftover screws are OK are incompetent. Screws are there for a reason -- they hold the board and other components in place. If thing start moving around, you run the risk of additional wear, and electrical shorts. Plus, if you have screws left over, there's a very good chance you made other errors as well. You should follow the guides on
  • Hey Hey John.

    I put most of it back together all except the bottom case/ lid thingy. It was nice to see the green light light up strong. The computer actually started up where I left off back in September 2011... same web pages opened as when it stopped working. I have noticed that the "O" and "I" # "9"buttons are not working. Also the power button is not functioning like normal. It did turn on just not on the first press. Kind of hesitant to turn it off again. I will though after in a few minutes.

    Im thinking that cleaning the DC- in board was what helped it power up as that is where maybe the liquid dripped, it was dark and sticky now its better. As for the keyboard think I saw the melted spot ...a few keys were fried. Anyway thanks for your assistance John I appreciate it.

    I was playing around a bit to try to hook up the white macbook to the mbpro to use the keyboad. Also i forget my password so no big deal... I might just start fresh and put the newer osx if it all works out ok. I am able to use it in guest mode so stuff is working almost. I may wait till I can order a new keyboard and DC-In from Ebay. And then the disassemble :) again... anyway odds are that I can do it again and get some work done on the machine. I hope this is all good and not some tep fix. I think there is a good chance the board is ok after all. Go green light!
  • gbkgbk
    edited June 2014
    i will add i got stuck on the blue screen turns out I did not snap in the orange optical drive ribbon. so i took stuff apart to get it hooked up have a red light and blue screen. ok it powered on again not with power button and battrire only with it plugged in. It said something about the date is set to something before 2008 yikes this is after i reset the date before hooking up optical drive.
  • writing this from the mbp with help of vurtal keyboard. think its ok....watching video and stuff think the blue screen problem is fixed yeah the orange ribbon was under the board so had to take it apart agian.....maybe the power button is working still not wanting to shut down
  • Cool, glad to hear it might be partly salvageable.

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