Random Mac Shutdowns...

[plaamook]

Anyone wanna help troubleshoot a potentially serious problem?

I now get completely random shutdowns on my mac. So far not when I'm actually using Reason or similar but either while it's asleep or when it's just idle/playing some music. Its just blinks and goes silent and when I go to check it out its on lock screen. I enter my password and it's closed everything down, lost all data on open projects, etc. I can't see a pattern to when it happens, what's running etc. It might be daily and then not for a few days. There's no time element (like it's been idle or asleep for x-hours). The only consistancy is that the screens is either asleep or on screen saver but I only say that because it's not yet shut down while I'm in mid-knob-tweak so to speak. I've switched off my screen saver so we'll see if that helps. I've reset the pram and smp multiple times. I've done a (nother...) clean install. I've turned most related things off in power management (see below). I've opened her up to check obvs hardware issues like RAM or HD.

Don't think it's the pmset-settings as they would mostly hybernate the thing while sleeping and this has started happening when it's not asleep. At any rate I've got:
standbydelay 4200
standby 1
womp 0
halfdim 1
hibernatefile /var/vm/sleepimage
sms 1
networkoversleep 0
disksleep 10
sleep 60 (sleep prevented by coreaudiod)
autopoweroffdelay 14400
hibernatemode 0
autopoweroff 0
ttyskeepawake 1
displaysleep 20
acwake 0
lidwake 1

System specs:
Late 2012 13" Unibody MBP
2.9GHz i7
OSX 10.13.6
14GB RAM (Crucial)
4TB SSD (Crucial)

I've been troubleshitting on the interwebs and it's a mine field of just about everything you could imagine. So I'm turning to all of you as folks round here tend to fart around with their computers an aweful lot. And I don't have any geek friends in real time. So, anyone have any experience with this or similar?

Anyone with some kind of insight and I'll strew data flowers on the ground before you as you go.

[bitley]

Overheated?

[plaamook]

Overheated?

You kidding? On Reason 10.3? I need to heat the thing up!!!

But no. Not that. It's deffo a fault of some description.

[kuhliloach]

I agree about the heat issue. Unfortunately this is most likely a hardware problem. You may need a fresh layer of thermal grease if perhaps the grease was not properly applied when the Mac was built. Or, perhaps a sensor is failing and the computer thinks its going to melt itself and shuts down as a safety mechanism.

[kuhliloach]

Also maybe try some compressed air on the CPU area in case its jammed up with dust. Dust can block ventilation which can trap the heat and trigger the shutdowns.

[plaamook]

Also maybe try some compressed air on the CPU area in case its jammed up with dust. Dust can block ventilation which can trap the heat and trigger the shutdowns.

I'll have another look but I was in there today and it was surprisingly clean.
Dunno about the greese, I'd have to look into it but it's not shutting down in association with any kind of task loading that would heat it up. In fact it never shuts down while I'm doing anything with it. Only when it's asleep or idle or simply playing music off of iTunes etc.
Also, wouldn't the fans kick in like mad if it thought it was over heating? This isn't happening that I've seen.

[pushedbutton]

I have a friend who's mac started doing this - conclusion was 'there's a dry connection on a pin somewhere'
Some people have had success fixing it by putting the motherboard in the oven and letting the solder melt. It's pretty risky but cheaper than a full point by point diagnostic. I wouldn't really recommend either.

[plaamook]

Yeah don't worry. I'm not taking my mother board out and putting it in the oven. But thanks for mentioning it.