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Model A1502 / 2.4, 2.6, or 2.8 GHz dual-core Intel processor / Released October 2013

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Device partial charge to 50%, runs off battery, no light on magsafe

Hi, hoping someone can give some advice.

I've done a lot of research on battery / charging issues, but I just wanted a further opinion before I proceed as I've seen a lot of variance on these problems both in their issue and the fix.

My Macbook Pro A1502, board 820-3476-A, has an odd issue that I'm not sure how to approach. This laptop was left with absolutely no charge in the battery for a time, and on returning to it, the magsafe went orange, and never came back on, and will not wake-up the device.

I did manage to charge it by leaving the magsafe there until it started, but now it only charges to at most 49% before the charger supplies 0Watts. If I run it down low, the laptop will report a normal charge, until it approaches 49%, after which it drops to 0.1, and finally 0Watts. The laptop will then run off the battery without issue. It will also run with the magsafe attached, and will maintain the 49% charge until I begin using it on battery.

All battery information from Coconut Battery (or equiv) reports normal operation. OSX battery indicator states "not charging", however has lightning bolt symbol and does indeed charge.

My question is:

Could it be a calibration issue (the battery is 5years old) and the 49% is in fact the new 100%, and the laptop just isn't aware of this? Could it be a magsafe DC board issue - the board is slightly corroded, and the magsafe adapter itself does not light up. Could it potentially be a component (J7000, U5000, U7100)?

The main reason I ask is because I've seen conflicting advice, and if I re-calibrate the battery (letting it die completely etc) it might never come back on again. I'm also not hugely experienced with the specifics of what readings I should get from a multimeter should I need to do that with the board.

Any advice would be appreciated.

Answered! View the answer I have this problem too

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Update on this. I've ran the Apple Diagnostics, and it reports that my charger was not analyzed/detected and there may be a problem.

Based on some other research, I think there may be an issue with the ADAPTER_SENSE / SYS_ONEWIRE. The DC in board is the only component I see that's corroded, so it's entirely possible that there's a problem with either Pin 6 of J7000 or Pin 5 of U7000. That would probably make sense as the laptop still gets power, it's just not able to interface correctly with the SMC (which is probably why SMC resets do nothing).

I will try and replace that and see if it helps.

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Another update.

I've run ASD on the laptop and it has reported two failures.

Sensor Failure = Current (IPBR) - reading below limit (value = 0.409180).

Sensor Failure = Current (ISDC) SSD 3.3V - reading below limit

I disassemble the laptop to remove the board so I can take a look for any obvious signs, particularly on R5429 for the IPBR error. I'm not sure what to look for yet on the ISDC failure, but I will hopefully figure this out as I'm not expecting any help on this question. I will keep updating though in case someone else comes across this issue.

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OK, computer is now fixed and working. Magsafe DC-in was dead.

If anyone has a similar issue, these are the steps I took (schematic naming convention may vary for you).

1) Measure power rails to see if they are all present. If you have PP3V42 your ISL most likely isn't dead.

2) Green light / charging issues are most commonly caused in the current sense circuit. Firstly check U7100 for CHGR_ACIN (4v).

3) Check to see if the ISL is talking to SMC - Pin 11 SMBUS_SMC_5.

4) Check for SMC_BC_ACOK on a probe point (3.42v).

5) Check to make sure U70001 has both SMC_BC_ACOK (3.42v) and PP3V42 power rail. Check your pullup resistor on U7000 (R7029).

6) Check all your resistors in general - R7110, R7111, R7122, R7121 etc. If your issue is like mine however these will probably be OK.

7) WHERE MY ISSUE WAS - Check your voltages on ADAPTER_SENSE and SYS_ONEWIRE. These should be 3.42v, mine measured at 1v. Issue was traced back to faulty magsafe DC board.

For further help, check out Louis Rossmann's YouTube series. Measure your rails and work backwards to find the problem. For current sense (i.e. battery not charging, no light) it's going to be DC-in, the ISL (U7100), a resistor on the circuit, or if you're really unlucky, the SMC.

Oh, and don't go ripping your battery out like the guy below suggests. Figure out the problem with your board first before you start making assumptions.

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Good diagnosis!

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Lithium batteries suffer most when left drained for good. In such condition they deteriorate and might get swollen and die completely. Given you battery history, it would be reasonable to replace it before concerning about anything else.

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Thanks for your reply. Battery has no swelling, thankfully, but I'm sure it has suffered some. I wanted to avoid a battery replacement, since that's quite a big task, but I accept that it may well have to happen. Still, I would like to try and isolate if there's another problem, to see if it's worth continuing or just saying I'm in over my head.

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Apple is offering replacement batteries at rock bottom prices! Or, do it your self! Here's the IFIXIT guide: MacBook Pro 13" Retina Display Late 2013 Battery Replacement and the battery MacBook Pro 13" Retina (Late 2013-Mid 2014) Battery

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Dusty will be eternally grateful.
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