I have a strange problem with the Mid 2012 (non retina) MBP 15 I recently purchased. When I bought it, the left shift control and alt keys were not registering key presses. All the other keys worked. I replaced the keyboard (that was fun) and nothing changed, to my surprise. I have done the usual SMC/PRAM resets to no avail. Short of using an external keyboard are there any other things to try? Could it be a dirty key board connector port, where the ribbon cable for the keyboard plugs into the mother board? Can that be cleaned? I am running Yosemite. Thanks in advance.
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Mid 2012 MBP 15 left side keys not working
- Thread starter BigCanoe
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The left shift, option, and control keys not working is a problem with the main logic board, unfortunately. We see this a lot with liquid damage.
It's very unlikely that cleaning the keyboard connector on the main logic board with a soft brush will solve the problem, but I suppose you could try if you like.
If you can stand to live with the problem, that might be best. Repairs for the main logic board are pricey (they start at a few hundred dollars).
It sounds like the seller might not have fully disclosed the condition of the computer, and I'm sorry for that.
It's very unlikely that cleaning the keyboard connector on the main logic board with a soft brush will solve the problem, but I suppose you could try if you like.
If you can stand to live with the problem, that might be best. Repairs for the main logic board are pricey (they start at a few hundred dollars).
It sounds like the seller might not have fully disclosed the condition of the computer, and I'm sorry for that.
Ouch, I was afraid of that. I can replace it myself but it looks like the parts alone are a few 100, sadly. All just to get 3 keys working 
Thanks for the information anyway!
[doublepost=1456502067][/doublepost]Is there any way to remap the FN key to be shift, or maybe capslock to be shift? Or a way to make a long press on a key be shift instead of repeating the key?
Thanks for the information anyway!
[doublepost=1456502067][/doublepost]Is there any way to remap the FN key to be shift, or maybe capslock to be shift? Or a way to make a long press on a key be shift instead of repeating the key?
Ouch, I was afraid of that. I can replace it myself but it looks like the parts alone are a few 100, sadly. All just to get 3 keys working
When you replaced the keyboard, you must have encountered the backlit that look like the image below (image credit: eBay).
I've circled the liquid submersion indicators. If it has liquid damaged, those indicators would turn from white to red.
It's very possible for the computer to get wet without any liquid-contact indicators tripping. And I agree, you probably would have noticed if there were bright red stickers in the computer.
Even if there was somehow no liquid damage, the fact remains that the main logic board is the faulty part here.
I'm very glad that it's a relatively benign problem, instead of the computer not turning on. However, if you bought it from eBay or Amazon, or if you bought it using a credit/debit card, you have a period of time during which you're protected against defects.
If you're going to open the computer to clean it, the only area that would be useful to clean is the keyboard connector on the main logic board.
Good luck.
Even if there was somehow no liquid damage, the fact remains that the main logic board is the faulty part here.
I'm very glad that it's a relatively benign problem, instead of the computer not turning on. However, if you bought it from eBay or Amazon, or if you bought it using a credit/debit card, you have a period of time during which you're protected against defects.
If you're going to open the computer to clean it, the only area that would be useful to clean is the keyboard connector on the main logic board.
Good luck.
No luck with the cleaning, same problem. I knew the keys didn't work but assumed it was the keyboard. Silly me. Thanks for your advice!
Sorry, I missed this part of your message.
I don't have personal experience with key-remapping software. I would think that training yourself to use the fn key for shift would be super-frustrating when you use a different computer with a normal shift key! But a Google search for remap os x keys found some software that would probably do the trick.
I hope you're not too frustrated with your MBP
.