Macbook Pro mid. 2012 15 inch (non retina)

I went back and found your older post where we chatted. I'd been traveling and got behind on my followups.

Did you do the display tests I mentioned there?

So got a deal on a One TB SSD...

What SSD did you use? "Good deal" makes me nervous; not all aftermarket SSDs sold as being "compatible" are. I will only use OWC or Crucial's MX (not the weaker BX) series when I do the HDD>SSD conversion on that model.

why are the innards to MBPs so freaking fragile?!

Downsizing goals and fragility seem to go hand in hand. I've seen plenty of Win laptops that were far less robust than my 2012 Macbook Pro and even more "stuffed into the case." Throw in a few years of kowtowing at the Altar of Minimalist Design and you get issues.

Remember the running "smallest cell phone" joke in the movie "Zoolander"? Methinks someone saw that as a design directive and applied it to laptops. How many times do notebook computer adverts tout "thin/light" over performance?

Sounds like this laptop has a bad GPU which is very common with the 15" & 17" models from 2008 to 2012 (and even some Retina models).

Definitely agree with the others that you purchased someone else's problems which have now become your problems. I would suggest just recycling the laptop especially if it has a bad GPU.....there is no reliable way of determining whether the GPU is bad since it does not always result in graphical artifacts...it can sometimes result in a laptop which won't even power on.

It sounds to me like you bought someone else's problems.

It's an old laptop. Laptop computers get abused. Such is their lot in life.

I have and use the same machine and it's been a workhorse since I bought it ten years ago.

There's a website that begins with "i", has "Fix" in the middle and ends with "it". You might check there as a source for replacement parts. And knowing how fragile these things can be, patience and finesse go a long way when working on the innards.

To be honest, though, that Mac wants to retire and you should let it. I wouldn't put much more money into it.