Question Macbook Pro 2011 keyboard issue: broken SMC card?

Aug 29, 2021
Hello everybody! I have a MacBook Pro 13’’ early 2011. Some weeks ago, it started having some problems related to its integrated keyboard; sometimes, right after switching it on, completely random, the keyboard wrote only symbols instead of letters. I checked language settings and looked for any stuck key, but I could not find anything unusual (consider that I had the keyboard replaced about two years before). Therefore, I thought it could be a software issue and, since I had had it in mind for a while to try ubuntu, I decided to install it, after making some hardware upgrade: I replaced the RAM with a larger one (2Gb + 2 Gb) and I replaced the hard disk with a SSD Samsung 870 EVO. Then I installed ubuntu 21.04. At this stage the keyboard does not work at all unless I press F6 using an external Bluetooth keyboard. By doing so, both external and integrated keyboard begin to work properly. However, after some minutes they both crash again (in the same way); in fact they begin to work only when using a few (apparently) random apps. Hence, I tried to reset the SMC, pressing the proper key combination according to Apple indications and, this way, the integrated keyboard immediately works at startup (no need of F6). But unfortunately only for a short time, after which not even F6 works. I add that I had the same problem after formatting the original HD (before replacing it with SSD) and installing ubuntu 18. This is my doubt: could it be that the SMC is broken? Could I solve this issue bringing my Mac to someone who can replace it? Or could I solve it by replacing the entire motherboard? O something else…? ☹ Thank you very much in advance to anyone who could give me an opinion about this mess!!