Random Keys Working Sporadically

Same issue ere as escribe. It's te mie row eys tat are not:

as;'

🙂

Comes and goes. Only thing I can add is that holding down the key (prolonged, not heavily) lets it eventually press. And then it will continue to respond for a while. It's like something confusing the kb scan.

THANK YOU for the fantastic close up shots posted here of the mbp kb guts! And as you can see by my typing here, the "issue has gone away..." for the time being..

Best - hth

-Bronius

Bronius,

Try plugging in a USB keyboard and report back the result.

Thanks for your reply! I tried:

• Without USB keyboard, the issue comes and goes on the mbp
• While it was occurring, I plugged in the USB kb, problem persisted on mbp but USB keys fired perfectly
• Left USB kb plugged in and worked on other things until the issue arose again; same results as before: mbp kb "D" key and neighbors lapsing, USB keys worked just fine

To better explain, here's more: While "it's happening," I am able to hold down the "D" key. Normally I would expect 1 D, a delay, and then a stream of Ds nonstop. Instead what I get is a long delay before the first "d" followed by a brief delay and then another "d" and then maybe a short burst of 3-6 Ds and pause and then another 1 and then delay, etc... However, if I get it to give a good burst, it may hiccup a bit before then consistently working again! There does not appear to be a pattern to it, and I strive to maintain constant pressure (not flexing or rocking the key or its neighbors). It's always only D-L from what I observe.

Apps I suspect might be messing with me:

• Tuck (really awesome, simple window manager by IrradiatedSoftware)
• Time Machine backup (it just ***** the life out of everything, doesn't it?)
• Chrome browser (Sometimes the issue appears to coincide with opening of a new browser ..)
• The Great Suspender (Chrome browser plugin which parks a tab to conserve resources)

...but I suspect it's not any one app but maybe some common thread messing with an OS level kb input scan or like Great Suspender freezing an operation at an inopportune moment.

Note: Nothing unusual in Activity Monitor like high CPU or something.. I believe a system restart clears the issue but it can return very quickly. I do restart with "restore windows," and my Chrome is usually 4 concurrent Chrome profiles and 12-25 tabs total across all.

"mbp kb "D" key and neighbors lapsing, USB keys worked just fine"

So it's clear to me that it's not a software issue:

"mbp kb "D" key and neighbors lapsing, USB keys worked just fine"

To explain the matrix design I recently replaced the top case in my 2011 13" MBP. I was interested in why the "Q - through - -P" keys all failed.

So I disassembled it.

This is the contactor array of a MacBook Pro 2011 13" . You're looking at it from back to front. Those round dots are where the silicone rubber "cones" cause the front array to make contact with the back array, telling the computer which key has been pushed. The width of these (I think deposited silver ) traces is about 0.5 mm.

Now you're only looking at the just the front array. You can see that the contact pads are connected in series. A break anywhere in the trace connecting them would cause the "downstream" keys to stop working.

So here you see a site where galvanic corrosion occurred.

So you can see from the amount of corrosion, it doesn't take much to cause a failure. In this case a drop of liquid less than 0.5 mm would, over time with galvanic action, cause a failure.

When I took this keyboard apart I was shocked to find how much crap was trapped under and inside the keyboard. Especially since I pride myself in never having any food/drink near my "precious!"

So in your case my theory would be that something got into the membrane between the front and rear. It's resistive but causing sporadic problems that are probably unrelated to what you're doing.

Thanks or reposting an reiterating. I'll give this USB a try (so hard to use the remapped keys and no trackpad!) while i work in a time to get my mbp into service. I take it that once disassembled, the membranes and loose parts can be a challenge to reconstruct, and it's not likely possible that any corroded connective wiring can be repaired.

" remapped keys and no trackpad!)"

Yup easier with a Mac keyboard and a mouse.

[edit] On your strong inclination that it's corrosion, short, or breakage, I am typing now on the mbp and wiggling the film between the problematic keys with a credit card in hopes of jostling the connection, and I believe it might be making a difference but can't be sure. There just aren't consistent observations: I've even visited this same thread three times in the past 6mo as it "seems to come and go in waves." My local mac store always says 3-5 days wait -- ain't nobody got time for that!. [/edit]

So if you look at the last picture in my illustrated post, see the "corrosion" area? Actually reading that area w/ an digital multimeter read 0 Ohms. So there wasn't actually a break there. If it did become discontinuous I can see how flexing of the film just by typing on the keyboard would make it come and go and that break isn't anywhere near the keys that would be affected.

" It's always only D-L from what I observe"

So look at the second picture "Y--E" since you're looking at the back it's backwards.

The next line of conductors down from there would be your "L--D". (Backwards right)

So a tiny break in that conductor path, and the path is about 0.5 mm wide, would make the downstream keys stop working.

I've actually repaired a similar problem w/ the automotive repair kit for rear window defrosters.

In the Early 2011 MBP 13" keyboard shown, there are 75 or more very tiny screws holding that membrane array to the top case.

My repair involved just replacing the entire top case. A total pain but better to do that than remove and replace those 75+ screws and have the replacement keyboard be faulty.

Hey hey - Just replying from my brand new, $45 keyboard:

http://www.amazon.com/gp/product/B008OIVV08/ref=oh_aui_detailpage_o06_s00?ie=UTF 8&psc=1

Took a good while, patience, and lots of screws to swap out, but I've not seen the issue since. Thank you for insisting your diagnosis (and putting up with my stubbornness). The mac shop in town quoted $360, and I'd have opted for the rush $85 fee as well. You saved me a bundle 😀

-Bronius

s"Just replying from my brand new, $45 keyboard"

Congradulations! Good job.

" lots of screws to swap out,"

I just did another one and there were 80+ screws in that one. The new keyboard did not have as many screws so I have 15 or so left over. It takes a tiny screwdriver. At least a PH00. I used a PH000 and just tried to find my PH0000 but it's lost somewhere in front of my nose. Another tip is to magnetize your screwdriver. Makes picking up those screws a lot easier.

The only other danger is the connector to the logic board. It releases with a lever at the back and it's difficult to get that large,multi conductor flex cable to seat properly. I use a piece of 3M Blue adhered to the outer radius and use the toe to pull the flex into the connector as I carefully guide it in. I learned that online somewhere and if you're reading this out there please take credit!

By the way there are cheaper keyboards out there. I just ordered one from L2:

http://www.ebay.com/itm/251314844078

So for any of you out there with an identical problem, this repair takes a bit of skill but is doable.

As bronius says it saved him $360

Hi,

I'm experiencing the same problem since september 2014.

The top row of letters doesn't work properly. The "P" is the only one that works fine.

I'm French but bought my laptop in the US in august 2011, it is a macbook air 13'.

It is not covered by the warranty anymore. I brought it to the Genius bar but I've been told that it was my fault and that they never heard of this problem before...

I'm in the US currently and am willing to start a class action. Please get in touch!

Lola

My MacBook Pro (early 2011) (I bought it refurbished and it had to go back to the Apple bar to be reset 4 or 5 times, installed a new hard drive and a new track pad before it would work properly. The track pad has always been an issue of sticking and it doesn't lay flat in the space and won't click unless your in the sweet spot.) But since I upgraded to Yosemite it has been nothing but random, off the wall issues. The keys stop working and start working again with no rhyme or reason. Especially the enter key. Still haven't found where the problem stems from.

"The top row of letters doesn't work properly. "

If you look at my picture post on the last page you can see how a tiny drop of liquid on that interconnecting trace on that row will knock out the entire row.'

That trace is only .5 mm wide.

I seem to have the same problem, with TYUIO failing as a group. If I press one of those keys for an extended period, then after some seconds it will show signs of occasional contact (the key on the Keyboard Viewer is highlighted just briefly), then more frequently, until the contact is permanent. Then the other keys also work again.

The problem can last for a few minutes or for days in a row, and the keyboard can also be stable for as little as a few minutes or as much as a week.

What I have noticed lately, with reservations that it may be a conincidence, is that if I press R and T simultaneously, even if it is just an ordinary, short key press, the keyboard will instantly work again, and it may stay stable for several days. Do others have similar experience?

"if I press R and T simultaneously,"

That's most likely coincidence but it is possible that an action like that will cause the discontinuity to temporarily self repair.

There has been theories presented here that say that this problem is a software issue but I can't see how that would work.

Replacing the keyboard has always worked for me. I always use new parts because I did do it once with a used keyboard and that one developed a "repeating

s key problemssssss". Made me nuts so I replaced it with new. New ones are cheap ~ $20. The normal protocol is to replace the entire top case which is ~ $175 in parts alone. The keyboard in the MBP is held in with 50 or so very tiny screws. I've done 5 of these so far and replacement always fixes it.