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Modelo de principios de 2011, A1278 /2.3 GHz i5 o 2.7 GHz con procesador i7.

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Battery / SMC issue..?

Recently I bought a very cheap 2011 MacBook Pro that was liquid damaged - only bought it because it was still running so assumed it wasn’t too bad.

Keyboard was definitely dead so I replaced with a brand new one now it works flawless. Also replaced charging port after reading here ( MacBook Pro not detecting battery (even after logic board replacement)) it might be faulty but looking back it was a waste of money as it didn't make any difference.

Then I bought a 85w charger as the one I had was 60w - actually made money with this as the brand new 85w cost me $20 and I sold the used 60w for $40 :)

Then I tried different batteries but system still shows ‘no battery available’. Also tried the batteries on another MacBook I had here and they were working fine and system showed ‘normal’ though with a bit over 1000 cycles.

When I unplug the charger the screen goes black but the laptop keeps running for a few seconds before it dies.

Charger keeps green light on all the time - it won’t go amber at all either the 60w or the 85w and regardless of laptop on or off.

Unplugged the BIL cable as it was suggested in another post here ( MacBook Pro not detecting battery (even after logic board replacement) ) and still no difference.


Now here’s the interesting part: when I bypass the SMC (unplug charger, hold power button pressed, plug the charger back, keep holding power button for 5-10 sec then let go and press power again to turn it on) the fans go loud but everything works fine even with the charger unplugged meaning the battery is holding charge and it does power the laptop even though system still says ‘no battery available’.

Here’s a video:

https://youtu.be/2cnQpiHTenc


I assume it’s a faulty SMC but I spent a lot of time online and couldn’t find a picture so I don’t know how it looks like or where it is located on the logic board.

So the plan is to either try to fix the SMC (once I know where it is - anyone has a picture?), try to replace it (unlikely unless I find someone with micro-soldering to do it) or try to keep bypassing the SMC and force the fans to slow down but I can’t slow it down via software already tried. Maybe some Terminal command could do it but which..?

Anyway has anyone had this issue and successfully fixed it?

Any suggestions would be appreciated :)

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Hello Carlos!

I just noticed this post. So, seems you are on the right track. There is some motherboard repair needed.

In my honest opinion thought, I would focus on the charging circuit. This is a somewhat common problem that can be caused by many different reasons! Water damage, non-original chargers, bad batteries, power spikes, and a few other things.

Firstly, I would check the ISL charging chip area for liquid damage/burnt out traces/ bad feed back resistors. This is very common and what would normally happen is this.

There are 2 sets of feed back resistors that tell the ISL charging chip how much energy the Battery or DCIN side is using. The ISL chip talks to the SMC and says whats going on with the charging/usage power.

If, for example, your battery side feed back resistors are having an issue (burnt up) the ISL charging chip will see some CRAZY number like your computer is using 238902 AMPs from the battery or something crazy like that. The SMC sees this, and tells the computer to EMERGENCY SHUT DOWN ! Because that could start a fire, blow up the house, cause the next WW3… that kind of thing.

Here is the catcher - if you are running off of wall power, the DCIN resistors could be fine, and your computer just sees the battery is trying to/isnt charging - but has normal power consumption (about 85w or closeish to 5 Amps) so the computer is running fine on wall power and the SMC thinks everything is fine. Until that cable is disconnected.

So, TL/DR. Check the ISL charging chip, its feed back resistors and go from there. I have a pretty good gut feeling though that the problem resides there. There are quite a few resources on Youtube showing the repair process and better explanations that what I have given. Micro soldering is needed.

Best of luck and Happy Repairing!

Joseph

Edit:

Here is the ISL charging chip. It is on the underside of the motherboard (opposite side of the CPU)

Block Image

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Thanks for that Joseph :)

Yeah I read about the ISL chip but I couldn't find it or any picture online that would be helpful as to where it is located.

The other diagnostic I found online was that the sensors (that row of leds that indicate the battery's charge) could be faulty and unplugging it might confirm - but it didn't, still the same issue when unplugged.

I also read somewhere that one of the resistors close to the battery plug might be faulty and bypassing with a trace - or the conductive paint I just ordered - might fix it. I'll try it as a last resort and if it doesn't fix anything I'll just sell the laptop on 'as-is' terms since micro-soldering is unavailable to me…

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I don't think i have a A1278 in my shop at the moment, but i will look tomorrow in the office to see if i can send you some sort of a picture what you could be looking for.

As for a resistor near the battery, that I haven't experienced yet. Jumping a resistor if it is suppose to be resisting is generally a bad idea. There are some very limited cases where it is ok (when the resistor is 0ohm for example)

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I got the info about jumping the resistor on this thread:

https://forums.macrumors.com/threads/smc...

Unfortunately it's 144 pages long and I was unable to find the post about this but basically it suggested that the resistor read something like 15ohms and was supposed to be 0ohm so they jumped it and it fixed the issue.

I'll try with conductive paint - which does resist a little - and see how it goes.

If it doesn't work I'll remove the paint - much easier than messing around with micro-soldering - and sell the laptop as is…

BTW: thanks for the diagram above :)

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Carlos Ferrari estará eternamente agradecido.
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