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jack
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Battery is not charging despite SMC reset

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Short Story:

The laptop will boot/run fine on a charged battery. It will NOT boot from the charger alone, nor will it charged a battery that is plugged in. Already tried resetting SMC and replaced DC-in board and charger.

Full Story:

This is a water damaged laptop (Received in that condition), that has been cleaned of corrosion, dried, etc.

Verified on other machines that the battery, DC-in board, ram, charger, etc all work.

The system WILL boot from charger ONLY when by-passing SMC.

I am not familiar with testing a board with a multimeter but checked the fuse next to the DC-in board and got a reading of 0, with the charger plugged in. I am confused since I thought that meant all power to the board is shut off by that main fuse, however, i get positive readings on the meter at other random places on the board.

I looked at the power-architecture pdf of the system as well and not sure what to make of the circuitry.

Not sure where to go from here. Thanks in advance.

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Update

Okay, wasn't sure how to post a screen shot onto my comment so i uploaded it online. Link: http://s27.postimg.org/qgvdtt4ur/photo_1...

This picture is of the laptop booted up from a charged battery AND with the AC adapter plugged in.

this is the laptop running on battery from coconutBattery 2.8

Block Image

Edited by: jack ( ) , oldturkey03 ( )

Have you checked the fuse for continuity, not just voltage?

oldturkey03,

Had no idea my multimeter could check for continuity until now. Just checked but not sure where to trace along the board to check this problem. I tried keeping one probe on the DC-in board and the other randomly over the board and i got beeps in random places. for instance, half of the battery connecter pins beeped and the other half did not.

jack,

Okay, that only means you have continuity somewhere, but it is not really beneficial to your issue. Have you just checked the fuse and does the fuse have continuity?

oldturkey03,

I only saw 2 white ceramic fuses, one by the DC-in board and one by the battery connecter. I checked both and both have continuity.

jack,

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Dan
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I would install this little gem of an app to see what is happening within SMC coconutBattery 2.8. Post a screen shot of what it has so we can see.

I suspect one or more of the FET's are burnt. Coconut can help narrow down what area.

Jack - Lets try disconnecting the AC adapter and see what Coconut tells us. Post a screenshot of the screen like before.

Dan,

Looking at your first snapshot the Battery power usage (bottom) is zero watts when you have the system connected to the charger so we know the that side is working. Looking at the second snapshot we now see 8.5 watts being drawn. So we now know the charging logic is only effected. As you checked the fuses we can focus on the FET and the logic which tells the FET to switch on.

Dan,

Review the following data sheets: P-Channel MOSFET & CMOS COMPARATORS. We'll need to know more exactly which logic board version you have to point out these components (and if I got the right schematic for your system). It's even possible your issue is salts & corrosion from the water damage around the contacts that is causing the comparator not to work correctly (a good cleaning with distilled water & high grade Isopropyl alcohol may fix it).

Dan,

Sorry, I thought I had the specific board information posted. The board is a 2010 2.4ghz core 2 duo board. i checked the board for FET's for corrosion and didn't see any. I cleaned up around a few FET's just to be sure and still the same situation.

jack,

Look at the edge of the logic board for the boards P/N. Apple had a few different versions.

Dan,

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Dan
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If your up to it this is what I would do:

Start by testing and if needed replacing the comparator (U7901 - TLV341 SOT563). It tests the batteries charge working with SMC and then switches the FET.

Then look at the FET (Q7950 - SSM6N15FE SOT563) which is the switch that sends the current to the battery from the charger Vs the system alone.

Edited by: Dan ( )

I guess i'm not sure how to start about with finding those components, testing them, and ultimately desoldering/resoldering such small contacts so i will stop there and just sell it. Thank you all for the help.

jack,

Do you have an Apple authorized repair station near you? They should be able to fix this and it would be cheaper than buying a new system. While Apple doesn't work on water damaged systems many independents do (abet with a limited warranty).

Dan,

of the places i contacted, they will only replace the logic board and not actually diagnose specific components on the board. that's not what i was looking for. so i'm going to continue and just sell this.

jack,

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