Logic Board Issues after Battery Repair

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Logic Board Issues after Battery Repair

I've been searching tirelessly for a solution to my MacBook Pro problems and stumbled across a post left by MacbookQuestionKB over a year ago, to which no one answered. Hopefully some kind sole can offer me some advice...

So, I had a near battery disaster on my 2017 15" MacBook Pro (A1707) in October last year (2020). The bottom case of my machine swelled up and rocked back and forth as the battery was close to catastrophic failure! (could have been in bed asleep.... just sayin'!!) Apple were quick to help and repaired under some service/quality scheme that they run on this type of issue. In order to repair, they replaced the entire top part of the chassis including keyboard and trackpad. All good... or so I thought for a while.

Wind forward to January 1st 2021, and I sit at my machine with my morning coffee, only to find that the keyboard and trackpad no longer function. I manage to get through to a friendly (always) support agent on January 3rd and, after several reset measures - SMC, PRAM, etc. - we conclude that another "common problem" has presented that will also be covered by the service/quality scheme.

Now I have to wait for what seems like an eternity for my local store to reopen because of COVID lockdown, and can kinda function with an external bluetooth keyboard and mouse. Finally I am able to drop my machine off on 2nd March. Great!!! Actually.... No!

The Apple repair depot reports back a week later that a tiny white dot has turned pink on the far right hand side of the logic board. Apple protocol clearly then states "Stop Immediately", quotes £1,429 / $2000 for a new logic board and to seek approval from customer! Jeez!!!!! I say no. Understandably! Might as well buy a new one!

Being reasonably competent in matters of electronics, and reeling in disbelief at their findings and at the quote, I set about my own investigations when my machine is returned to me. I've had the logic board out and investigated every millimetre and component on both sides under a bright light and magnifying glass, and there is absolutely no trace of liquid damage to be seen anywhere. I'm not denying the pink dot, but there must be some other explanation for it to have changed colour.

The facts remain that there is no liquid damage anywhere, and the replacement parts that were installed as a result of my battery failure have themselves now failed. And Apple will not repair it seems.

It "feels" like the keyboard and trackpad drivers have gone AWOL. Does anyone know how these can be checked or reprogrammed or reinstalled? I have tried a suggestion of deleting the .plist files for trackpad and mouse and then restarting. No joy. I've tried two Big Sur rebuilds/recoveries with same results. It all seems just a bit odd!

Maybe the logic board has developed some fault, but everything else is working just fine. I mean EVERYTHING. You'd expect something else to be at least "glitchy" if the logic board was failing. Why just the components that Apple themselves replaced for me late last year?

Which component or components on the logic board look after the keyboard and trackpad? Someone has suggested the SMC chip, but I'm not convinced. This apparently looks after things like keyboard light, power button, fans, etc. No mention of keyboard and trackpad, if you're to believe everything you read on line.

Anyway, you're all probably bored by now! Any advice or tips will be gratefully received.

Thanks for reading! 😁👍

MacBook Pro 15″, macOS 11.2

Posted on Mar 18, 2021 11:09 AM

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Answer 1

Top-ranking reply

HWTech

Community+ 2026

Level 9

74,338 points

Mar 19, 2021 10:41 AM in response to Marko-UK

Marko-UK wrote:

It has now been suggested by another UK repair facility that it may be the trackpad alone that is causing the problems, since communications go here first (apparently). If the trackpad has failed, then that'll take the keyboard out as well. Or so I'm being told.

Yes, that is true for some Apple laptops and I think it may also be true for the 2016-2017 model too, but I'm not 100% certain. I know for sure that on the 2015 model just disconnecting the Trackpad cable from the MLB is enough to stop the Keyboard from working (the Keyboard has its own connector on the Logic Board). I think I had the same thing happen with the 2016-17 model as well.

Anyway, I really appreciate your help, and will head down this route first. I can pick up a brand new OEM trackpad for around 40 bucks, so will start here.

If you do this, then don't remove the original one until you test the new one. You should be able to connect the new trackpad and very carefully place the laptop on its side with the display open making sure to hold the new trackpad away from any of the electronic just so you can perform a very basic test to confirm it changes things.

Good luck.

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Answer 2

Mar 19, 2021 10:56 AM in response to Marko-UK

Marko-UK wrote:

It has now been suggested by another UK repair facility that it may be the trackpad alone that is causing the problems, since communications go here first (apparently). If the trackpad has failed, then that'll take the keyboard out as well. Or so I'm being told.

I have just confirmed the Keyboard does not work if the Trackpad Cable is disconnected from the Logic Board on a MBPro 13" (2017) Touchbar model.

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Answer 3

Mar 19, 2021 9:17 AM in response to Marko-UK

If the laptop powers on, then the SMC chip is most likely fine since the SMC chip controls the power circuit to power on and charge the laptop. If it is a power issue, then most likely the problem is some other component or perhaps even just the Top Case/Keyboard/Trackpad Assembly. I would start out simple with what I suggested earlier --- the Logic Board needs to be tested with another Keyboard or another Logic Board needs to be tested with your Keyboard/Trackpad. It is as "simple" as that.

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Answer 4

Mar 18, 2021 6:09 PM in response to Marko-UK

Sometimes the Apple liquid sensors can be triggered by high humidity. But it is also possible a little bit of water did hit the liquid sensor. I've had users admit to spilling water on their laptops, but I'm unable to see any signs or traces on any of the internal components. Other liquids will usually leave some signs of residue or even corrosion. I'm pretty good at noticing the subtle signs after doing this for 20 years. You do need to use a magnifier to really check the boards for the subtle signs.

As far as troubleshooting the issue you really need to swap in a known good part. You either need to test your Logic Board in another identical Mac or you need to test another Logic Board with your Top Case/Keyboard Assembly. As a first step I recommend disconnecting everything except for the battery and display. Then disconnect the display and reconnect just one of the I/O Board so you can test the laptop with an external display.

If the external keyboard & mouse don't always work either, then try disconnecting both the keyboard & trackpad from the Logic Board and see how the external keyboard & mouse work. Do you have the same issue when using a wired USB keyboard & mouse?

These USB-C Macs are not easy to troubleshoot as they can behave very strangely making it extremely hard to figure out which part is really bad. I once had an internal Display Assembly prevent a USB-C Mac from booting which looked like a Touchbar failure. There are times when nothing makes sense with these USB-C Macs.

Good luck.

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Answer 5

Marko-UK Author

Level 1

9 points

Mar 19, 2021 4:02 AM in response to HWTech

Thanks for your reply.

I can only imagine that moisture has got in and caused one single dot on the far right edge to go pink (next to the long rectangular foil covered set of components - does anyone know what tasks these chips perform?). None of the other dots in the machine have changed at all. I'm with you on the residue front, but I've stared at every square millimetre of board for hours, with particular focus on the area near the dot on both sides of the board, and cannot find anything. Even under the foil on both sides.

I've not experienced any problems at all with a bluetooth connected keyboard and mouse. Both also work fine connected via USB with bluetooth disabled. Everything about my machine is operating perfectly with the exception of the replacement components installed by Apple.

So I'm left with a component level investigation by a local MAC repair specialist claiming to be able to repair logic boards at a fraction of the cost of the Apple quote. Fingers crossed this is the right decision, although I'm still not 100% convinced that this is not a BIOS level driver issue. On the phone they immediately suggested that the SMC chip has failed and needs replacing. Any thoughts?

Thanks again. M

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Answer 6

Marko-UK Author

Level 1

9 points

Mar 19, 2021 9:52 AM in response to HWTech

Very helpful, and thanks so much. I was thinking along the same lines re the SMC chip.

I am certainly going to try and find a way to check matters as per your suggestion before folks start reworking/reflowing the logic board. It has now been suggested by another UK repair facility that it may be the trackpad alone that is causing the problems, since communications go here first (apparently). If the trackpad has failed, then that'll take the keyboard out as well. Or so I'm being told.

Anyway, I really appreciate your help, and will head down this route first. I can pick up a brand new OEM trackpad for around 40 bucks, so will start here.

After two attempts at recovery, the appearance of a duplicate "Macintosh HD - Data" volume, several failed backups, and a backup disk reformat, I'm just waiting for a new backup to complete first before I get my tools out again! Why do these things take so long?? Nearly 20 hours in and still 10 hours remaining! (I tried the disable throttle setting to no effect!)

Just got to be patient! ;-)

Thanks again. M

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Answer 7

Marko-UK Author

Level 1

9 points

Mar 19, 2021 12:14 PM in response to HWTech

This is so helpful. Thanks so much again, and thanks for testing.

It's difficult not to get excited that we may be on to a significantly cheaper solution. Patience is a virtue though.... still 8 hours left for the new backup to complete!

I'll let you know how I get on.

Huge amounts of gratitude! 👍👍

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Logic Board Issues after Battery Repair

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