Control, Option, and Shift keys (on left side) do nothing.

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MacBook Pro 15" Retina Display Mid 2015

2.2 GHz (Turbo Boost up to 3.4 GHz), 2.5 GHz (Turbo Boost up to 3.7 GHz), or 2.8 GHz (Turbo Boost up to 4.0 GHz) quad-core Intel Core i7 processor with 6 MB shared L3 cache.

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Brian @slavetothesound

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Posted: Nov 12, 2019

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Control, Option, and Shift keys (on left side) do nothing.

I just replaced the logic board on my sister’s Macbook Pro 15” mid 2015 Retina. Now the left side Control, Option, and Shift keys are not functioning. The keys do not register in the keyboard viewer. The replacement logic board was purchased from iFixit, so I’m assuming it should be fully functional.

I’ve tested in safe mode, a new admin profile, and even booting from another MacOS installation on a USB stick.
I’ve reset the NVRAM.
I’ve reset the SMC (by unplugging the battery and holding the power since the necessary keys do not work).
I’ve re-seated the keyboard connector multiple times (and the trackpad connector for good measure).

Questions:

Is there anything left to try?
Which piece of hardware should I be looking at?

Answered! View the answer I have this problem too

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Why was the logic board replaced ?

Nov 13, 2019 by arbaman

@arbaman The laptop stopped charging. It worked fine while it slowly died, then couldn't be charged at all. We also replaced the Magsafe 2 board during that process and I bought an expensive genuine Apple charger since she was using one someone had given her. It had wire exposed and looked to be in very rough shape.

Could it be possible that the keyboard was damaged at the same time as the logic board? It went unnoticed until we replaced the logic board and I watched her struggle to log into internet accounts for an hour before she realized the shift key was causing her to type passwords incorrectly.

Nov 13, 2019 by Brian

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arbaman @arbaman

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Posted: Nov 13, 2019

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The bad Magsafe charger explains why the old board stopped charging, too bad, it was a very expensive charger in the end although the charging circuit could be fixed by a component level repair, that comes cheaper than a replacement. However, I never experienced a keyboard going bad as a side issue of a faulty charging circuit, the problem must be somewhere else. Shift, control, option and power buttons have a double function in a keyboard as they’re connected to the SMC for reset and other system toggles. Unless you had a spill, big or small in the past, or keyboard has gone bad out of the blue, there might be a board SMC issue. I’d try if a SMC reset works as a first thing. As a second step I’d try again your old board to double check there isn’t a keyboard failure. I know it’s a headache but a KB replacement on a retina is a big job and a topcase replacement pretty expensive..investing a couple hours work in troubleshooting seems to me the best option.

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I didn't think to put the old logic board back in now that I've been able to charge the battery. I'll test that in the morning. Thanks for the idea!

Nov 13, 2019 by Brian

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@arbaman The laptop stopped charging. It worked fine while it slowly died, then couldn't be charged at all. We also replaced the Magsafe 2 board during that process and I bought an expensive genuine Apple charger since she was using one someone had given her. It had wire exposed and looked to be in very rough shape.

Could it be possible that the keyboard was damaged at the same time as the logic board? It went unnoticed until we replaced the logic board and I watched her struggle to log into internet accounts for an hour before she realized the shift key was causing her to type passwords incorrectly. — Brian
I didn't think to put the old logic board back in now that I've been able to charge the battery. I'll test that in the morning. Thanks for the idea! — Brian