Keyboard damaged by overheating? Double letters..

[mca1310]

Hi all, I know the keyboards failure have been extensively discussed in many threads but I've never been able to find my specific problem.

I have MBA 2012 and I have replaced my keyboard two time already. The second time the keyboard worked well for 4 months and then the same exact problem of the first one (lasted 5 years) appeared again.

In short when I type some specific keys (always the same) I get two letters on screen. E.g. if I type 'a' I get 'as'. If I type 's' then I get 'as' too. Such problem happens on key '1,2,q,w,a,z,x' and on some function keys like 'back delete' which activates the 'tab' at the very same time. Note that the problem can persist for long periods but it's not permanent. In the last two weeks since the problem appeared again, I had a couple of days where everything was working fine.

The problem is definitively hardware because everything works perfectly with software (I'm using it in this very moment) or external keyboard.

I suspect the problem is very connected to a high temperature of the CPU and I'm planning to replace in coming days the thermal paste.

Did someone experienced the same problem?

Many thanks!

 

[Mrbobb]

Just throwing guesses out there, high temp making metal soft/warp and causing kbd traces contacts?

My CPU hovers ~50c, fan mostly running 2,000 rpm (reeves up as load increases per design), and NEVER had a keyboard problem, and don't feel any heat under my palm/fingers, am guessing the heat vents are working properly as should. Once in a while I touch the bottom and that gets warm but not always that's about it.

 

[mca1310]

What is puzzling me is that, looking around, no-one reported similar problem. Most people have problems related to dirty/dust which is not my case since I'm regularly cleaning the logic board and vents to lower temperature. The other strange thing is that both keyboards have problems on same keys. By the way the keys closest to CPU have no problems but those behind the fan are failing. I can't really understand what's going on...

 

[mca1310]

Ok, I have proceeded with a more analytical approach. In the past days I've opened the MBA and disconnected battery, "bus" on the right and the keyboard cable and the issue was resolved for half an hour (only). Today I've been more methodic: I've disconnected the battery and the problem was still persisting. Then I've reconnected the battery and disconnected the keyboard cable on trackpad. This time the problem was fixed. Apparently the problem is around the keyboard cable and its connector on trackpad. It is still working since an hour or so. Let's see.
PS both connector and cable were looking clean

 

[mca1310]

So, the fix this time worked fine for less than two days. I've tested the MBA heating it up with some games, temp was not excessive (around 85C) and then I've closed it for a while. When I've restarted it, the problem appeared again. At that point I've reopened the MBA, disconnected the cable of the keyboard, cleaned everything again (cable and connector) and now everything is working fine again...for the next few hours. Very annoying.
In the last hours I'm questioning the trackpad. Do you know whether there is any intelligence in the trackpad managing the keyboard or it's just a "wired bridge" to the logic board?

 

[Regime2008]

So, the fix this time worked fine for less than two days. I've tested the MBA heating it up with some games, temp was not excessive (around 85C) and then I've closed it for a while. When I've restarted it, the problem appeared again. At that point I've reopened the MBA, disconnected the cable of the keyboard, cleaned everything again (cable and connector) and now everything is working fine again...for the next few hours. Very annoying.
In the last hours I'm questioning the trackpad. Do you know whether there is any intelligence in the trackpad managing the keyboard or it's just a "wired bridge" to the logic board?

85C?!?!? I would return it at that point. Something doesn't sound right for HIGH temps like that,

 

[mca1310]

85C?!?!? I would return it at that point. Something doesn't sound right for HIGH temps like that,

Well, consider it was 3D game simulator. Said that I agree with you that we can optimize the temperatures and this is why I'm planning to replace the thermal paste as soon as I receive it.

 

[mca1310]

Quick update.
I've finally managed to replace the thermal paste of the CPU. The operation is pretty simple and there are a lot of useful guides online (youtube). Only suggestion: do not fix too much the screws of the dissipator above CPU, the support may break.
Said that, initially I didn't notice a big difference. CPU T° was around 50-60° in normal work and was increasing up to 102° on very heavy 3D game (for about a minute during the upload of the simulator).
Three days after, situation is significantly different. The MBA is now running between 35° and 48° in normal work and do not go above the 99° on the 3D simulator. I therefore warmly recommend to replace the thermal paste if your MBA is suffering high T° (mine is "Artic" bought from ifixit).
The other good news is the keyboard. No more problems since a week now even after playing the 3D simulator. As mentioned above the solution to fix the problem was to unplug and plug the keyboard connector on the trackpad. Last time however I've noticed (probably due to high T°) that the plastic on corner of the connector was slightly peeling. I've replaced it very carefully in its original place and connected again the connector. Since then no more problems, let's see in the coming weeks/years
Hope this help anyone that may have the very same problem in the future.