exxos's Atari, Amiga & retro forum

Well, I've posted about my 2012 MBP over on my general thread as it was my workbench machine running both Windows and Mac OS, and being quite compact it was super useful.

Until that is the keyboard stopped working...

I faffed about trying PRAM and SMC resets, leaving power off for a month, then when that seemed to work I reinstated it only to have it go again. I tried an OS rebuild from scratch, but nope, it just came back again after a short while.

The symptoms are odd, in that it will go from working to not over a period of time and when typing you seem to get Greek characters and symbols rather than English!!!

I figured that I had a mainboard fault, so managed to find a replacement logic board on eBay for the very reasonable price of £35 shipped. It arrived today, and is really quite easy to fit.

I fitted it, tested it and all seemed good. Until that is during another OS rebuild, out came the random Greek characters again. Damn.

So, I think the problem is the keyboard :dizzy: as that's all that's left given I'm getting the same issue on 2 logic boards.

Ho hum.

At least the keyboard on this model is held in by screws as far as I can tell. More on that later...

The greek characters are usually the result of the Option key being pressed, did you check if it's not stuck or have a short ?

olivier.jan wrote: 22 May 2024 14:51 The greek characters are usually the result of the Option key being pressed, did you check if it's not stuck or have a short ?

lt is possibly a short, but I need to pull the keyboard out to check there are no bits of debris in there, so I can expect a lot of screw removal in my future...

I've seen this failure mode before, on an external keyboard. It's basically the keyboard processor going do-lally. It's throw the keyboard away time.

stephen_usher wrote: 22 May 2024 15:40 I've seen this failure mode before, on an external keyboard. It's basically the keyboard processor going do-lally. It's throw the keyboard away time.

I suspect @olivier.jan is correct and that I have a faulty OPTION key as I can replicate the characters I see on the faulty machine on my current M1 MBP by holding down option and typing.

Instead of Jon, on the bad machine I get ∆ø~ which matches Jon when typed with OPTION held down.

I can't imagine 2 totally different mainboards are bad, so that just leaves the keyboard, and I have a new one ordered. It's supposed to be here today, but it's not dispatched yet...

Also, the problem is apparent with external keyboards too, so given all the evidence, I think a bad keyboard is most likely.

I'm not sure that the MBP keyboard has any sort of processor as it's so damn thin, but I guess I'll find out when I pull the old one out.

The keyboard in the MacBook Pro is USB, just with an internal, non-standard cable.

stephen_usher wrote: 22 May 2024 21:44 The keyboard in the MacBook Pro is USB, just with an internal, non-standard cable.

That honestly wouldn't surprise me, and if the option key does have a short and is stuck down, I'd expect the same result with any external keyboard, which is what is happening.

Will look at it more later, but will be out for most of the afternoon as it's my annual diabetic eye check.

If you unplug the internal keyboard ribbon, an external one should be working correctly.

olivier.jan wrote: 23 May 2024 09:52 If you unplug the internal keyboard ribbon, an external one should be working correctly.

There is one slight flaw with that plan (I know as I tried it) the power button comes through the keyboard, so if it's unplugged you can't power it on, and though I had planned to try and unplug with the power on, I didn't get round to it.

I took the old KBD out before starting work, there are a lot of screws:


This will be the reason, along with the solid unibody deck, that apple keyboards don't have a lot of flex.

And these fell out of the keyboard as I was removing it:


And I'm guessing one or both could be the culprit.

Since I have a new keyboard coming and I don't know if either of these caused any other damage, then the old one can stay out and we should be good to go. I will need to be more careful to avoid small bits like this getting inside again, however it's usually closed, so not entirely sure how these got in, but there you go.

The second one looks like swarf from the machining of the Unibody case!