Macbook Pro 15" freezes and "3 beeps"

[C0ton]

Hi!

I have a Macbook Pro 15" mid 2012 (right before the Retina). Recently I've had some issues with it.

A few days ago it froze and after a few seconds the screen went black and it started beeping 3 times (then pause, then 3 more beeps, etc…). I shut it down by pressing the power button for a few seconds and turned it back on after a few minutes and it booted up fine. Then a few moments later it did it again.

Since then it's been happening from time to time, seemingly randomly.

I looked it up and that sound appears to be the sign of a bad RAM so I opened my laptop , took the RAM out, cleaned it and placed it back (switching both RAM sticks) but yesterday it happened again. The computer starts up and works fine the rest of the time, it just has this "incident" happening from time to time.

Could it still be a bad RAM problem?

I should mention that in hope of fixing whatever software issue, I updated to macOS High Sierra from El Capitan, which doesn't seem to have done anything. Also, over the course of the 5 years I've had this computer I replaced the RAM for 2 8go sticks (DDR3, 1600 MHz), took the Superdrive out to put the Hard Drive in its place and added an 500go SSD in the Hard Drive's place. Those modifications took place more than a year ago and the Macbook has worked perfectly until now.

Before it started doing the 3 beeps things though, over the past few months the fans would sometimes start spinning really fast when doing some really mundane tasks and I noticed in the activity monitor that a kernel_task was sometimes taking up a few hundred % of the CPU for no apparent reason. Could that be linked to the problem I'm having right now ?

I know 5 years can now be considered a good amount of time and I should consider upgrading to a newer laptop but after spending a few hundred bucks upgrading the RAM and the SSD, I don't want to give up before at least trying to fix it, especially since the newer Macbooks are incompatible with both so I wouldn't even be able to transfer it to a new computer.

Do you guys have an idea of what I could try to fix it?

Thank you!

 

[elf69]

have you got the old ram to try?

try one stick only then if ok try other slot, might have a duff slot?

 

[C0ton]

Ok I'll try that.
It might be a while before it starts acting up again so I guess I'll spend the next few weeks with only half the RAM in.

I have the old 2x2go of RAM lying around somewhere too yeah.

 

[elf69]

try just one 8GB for bit in one slot. if all good for a while try in other slot.

if still good try the other stick.

stick or slot is my first reaction to this.

 

[Fishrrman]

2012 MBPro's had reliability problems with the internal SATA ribbon cable (to the hard drive).
This can be a problem on 13" models, not sure about the 15".

When the cable goes bad, the result will be interrupted/intermittent communication between the drive and the motherboard. From the user's perspective (and from the perspective of the OS), it might "seem like the drive has gone bad" -- but's it's only the cable.