"Hey everyone, after having this problem, i found out the problem might not be the soldering at all. read on...
I have a MBP 15"" early 2011, had the logic board replaced in the apple program for the video chip, after that, i started to get kernel errors once in a while, all was pointing to RAM, but could never actually find a defective stick and tried many, after a while of seating and reseating the sticks and a fresh install os the macOs it stopped for almost a year with no problems i thought i was done; only to begin crashing, powering off and beeping this week.
i've been reading forums about this problem and after watching this video
https://www.youtube.com/watch?v=xpagfXra...
I'm having exactly the same problem as this.
So I took it apart again, and what did i find... apparently, as i said, and for everyones happines it migh not be the soldering at all!!
It seem the CLIPS that hold the stick closest to the keyboard are worn and do not have enough pressure so they do not hold the ram in place all the time, a little bump and the RAM stick springs up like half a milimeter and the problem appears.
What did i do? Got a 1.5mm (.60 cal) piece of flat styrene about 3mm wide and 7 or 8 mm tall, put BOTH RAM sticks in place and with a little plastic tip/spudger push down the stick closest to the keyboard so the clip can make its full travel inward and insert the styrene pieces one in each side in the slots between the clip and where the screws for the bracket are and then push them towards the RAM contacts to make pressure inward so the clips are pressed firmly against the sticks (you wont be able to remove the sticks without removing this styrene pieces).
I did this, the MBP started with no problems, i can now shake it and won't freeze and/or beep at all.
I'll try to make a video or at least a photo guide showing what i mean and post the link (it will be my first YT video so be nice hahaha) so it shows the fault and fix clearly."
"I tried the credit card solution but I wedged the plastic in between the two ram slots and that has fixed my problem! Well for now…. I was testing the slot by applying pressure to multiple spots and nothing has crashed!
"I had the same issue with my Macbook Pro mid-2012 13-inch. The symptoms would gradually progress like this:
after taking laptop out of my, it would be frozen (black screen, breathing light stuck to 'on')when picking up the laptop while open, screen would display those horizontal stripes / blocksshortly after that, it would progress to the three-beeps situation and not being able to find the RAMthere were side effects, like a confused Wifi and MS Outlook crashing its identity, but those were symptoms not causes
After taking it to the repair folks, it would often work without problems again for a long time, even though they had no clue what the cause was. Strangely, taking the RAM sticks out and plugging them back in was not always effective. Or not for long. But sometimes it was.
I was so happy to read Santiagodelatorre's analysis. *That* finally made sense to me. And his solution seems to work for me too.
At the end of the RAM clips, there are little round protrusions that fit in a round opening in the side of the RAM stick. But those are not actually what holds the RAM sticks in place. You need to look even more closely for small plastic 'wings' that extend from those round protrusions.
Photos in a public Google photos album.
(Note on the photos: there are two photos that are almost similar. Except in one, the RAM stick is being held down below the plastic wing, whereas in the other, that's not quite the case. Hard to see, but very real)
Those wings (same material, same color as the rest of the clips) are meant to be flat at the bottom. So that the RAM stick rests against them: flat surface to flat surface.
As you can see in the photos, these wings have become degraded: they're not smooth like the rest of the plastic parts of the RAM clips. It almost looks like the plastic is just falling apart by itself. It doesn't look like wear and tear. Perhaps the sticks get too hot for the plastic.
In my case the protrusion on one side was no longer perfectly flat at the bottom. This was the wing for the bottom RAM stick. Since the RAM sticks are actively pushed upwards and the wing wasn't quite on top of the RAM stick, the stick would gradually push the clip aside, and thus the stick would move upward just a little.
Presumably that causes the memory problem.
This is why shocks (like the laptop receives when I put my bag down) would cause the problem to start. And why the problems gradually got worse. And why there are moments, near the end of that cycle, where the laptop will work fine while flat on a surface, but will crash as soon as I gently tilt it away from me.
I solved the problem similarly to Santiagodelatorre, except with a bigger segment of cut-up credit card, and only on one side."
