MacBook A1278 no display.

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2011年末 MacBook Pro 13" 一体化机

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Yusuf Kadi @yusuf_kadi

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发帖于: 2019年11月30日

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MacBook A1278 no display.

Hello.

I've been having a problem with a 2011 MacBook model A1278. I was expecting to replace a battery and repair a hard drive, but after that was finished the laptop wouldn't start. The magsafe charger shows a green light when plugged in and the battery indicator lights work. When the power button is pressed, the fan starts spinning. It turns off after about a second. When the battery is disconnected and the charger is plugged in and the laptop is powered on, the fan spins for one second, stops, then repeats this cycle until unplugged.

I've brushed the motherboard and scanned it for corrosion, but I've found nothing. I've included a picture below of the charging port logic board, which has some substance on it. I'm thinking corrosion, but the laptop receives power from the charger and the charger recognizes the laptop.

I've also found some IC chips with a hot glue like substance on them (pictures below). Has someone worked on this board? Any help is greatly appreciated.

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The glue is called potting when used on a logic board. Its used to prevent the humidity in the air from effecting the component. Some devices use very little differences to measure changes in state.

Often I find people take it off to fix a board and fail to put it back on or the person cleaning the board decides its not needed. So don't remove it unless you put it back!

The gloss on the high current areas is most likely a lacquer coating used to protect the exposed solder joints. You also will encounter flux coating some parts as well.

由 Dan 完成的 2019年12月1日

@danj I thought it was flux (but solid???) from someone working on the board. I'm glad to know that its normal. I haven't touched it caused another problem. :)

由 Yusuf Kadi 完成的 2019年12月1日

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arbaman @arbaman

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The transparent coating is factory work, nothing unusual. The quarter fan spin is often times associated with current sensing or with CPU related rails or components, nothing you can fix unless you’re experienced in logic boards repairs.

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Thanks for the answer.

I'd like to try everything before abandoning this board. Do you think that the charging board could have anything to do with this? Its the only corroded part I see, and the laptop behaved differently when it was charging vs not charging.

由 Yusuf Kadi 完成的 2019年11月30日

@yusuf_kadi If you are thinking about the DC-in board I'd say no, since you have a steady green light with the Magsafe, that proves power gets correctly to the board. It's a very simple part..either it works or it doesn't.

由 arbaman 完成的 2019年12月1日

@arbaman I've been thinking about this MacBook and I just remembered that I was told it had an aftermarket battery put in. Could a low quality battery have blown a component in the current sensing system?

Also, for future reference, do low quality batteries blow components upon being powered on or in the long term?

由 Yusuf Kadi 完成的 2019年12月1日

@yusuf_kadi It's always a bit hard to determine what exactly caused a failure, but I encountered a few boards where current sensing faults were found after a bad battery was removed, even with original batteries. Damage was usually rather causing slow charging problems, I can't remember a more extensive damage, but it might be a possibility.

由 arbaman 完成的 2019年12月1日

@yusuf_kadi - Fake chargers are more of a concern than 3rd party batteries.

The safety elements Apple designed in the charger are missing within the fake chargers, which puts your system at risk! Counterfeit Macbook charger teardown: convincing outside but dangerous inside & Lacking safety features, cheap MacBook chargers create big sparks

由 Dan 完成的 2019年12月1日

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The glue is called potting when used on a logic board. Its used to prevent the humidity in the air from effecting the component. Some devices use very little differences to measure changes in state.

Often I find people take it off to fix a board and fail to put it back on or the person cleaning the board decides its not needed. So don't remove it unless you put it back!

The gloss on the high current areas is most likely a lacquer coating used to protect the exposed solder joints. You also will encounter flux coating some parts as well. — Dan
@danj I thought it was flux (but solid???) from someone working on the board. I'm glad to know that its normal. I haven't touched it caused another problem. :) — Yusuf Kadi
Thanks for the answer.

I'd like to try everything before abandoning this board. Do you think that the charging board could have anything to do with this? Its the only corroded part I see, and the laptop behaved differently when it was charging vs not charging. — Yusuf Kadi
@yusuf_kadi If you are thinking about the DC-in board I'd say no, since you have a steady green light with the Magsafe, that proves power gets correctly to the board. It's a very simple part..either it works or it doesn't. — arbaman
@arbaman I've been thinking about this MacBook and I just remembered that I was told it had an aftermarket battery put in. Could a low quality battery have blown a component in the current sensing system?

Also, for future reference, do low quality batteries blow components upon being powered on or in the long term? — Yusuf Kadi
@yusuf_kadi It's always a bit hard to determine what exactly caused a failure, but I encountered a few boards where current sensing faults were found after a bad battery was removed, even with original batteries. Damage was usually rather causing slow charging problems, I can't remember a more extensive damage, but it might be a possibility. — arbaman
@yusuf_kadi - Fake chargers are more of a concern than 3rd party batteries.

The safety elements Apple designed in the charger are missing within the fake chargers, which puts your system at risk! Counterfeit Macbook charger teardown: convincing outside but dangerous inside & Lacking safety features, cheap MacBook chargers create big sparks — Dan

2011年末 MacBook Pro 13" 一体化机

MacBook A1278 no display.

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