Laptop powers off unexpectedly in Windows and Memtest - RAM problem?

[Suv_Chuck]

I've got a Lenovo Y40-70. Yesterday, it started to power off randomly soon after I turned it on. It happened while the computer was both plugged in or unplugged. I checked the Event Logs, which Windows had filed as Event 41. There was no BugCheckCode or PowerButtonTimeStamp listed, which lead me to believe that this was a hardware problem. So, I tried booting into the Memory Diagnostic tool included with Windows. The computer shut down right after I passed UAC. I tried MemTest86 after that, and that ran without error until it shut down as well. Now I'm not sure if this is a clear indication of a ram problem or if there's some other issue. The only thing I can think of is heat. MemTest86 last logged 65C for the processor, but I don't believe that's very hot(?).

I'm sort of at a lost as to what to do next. I'd appreciate your guys opinion as to what you think the best next steps are. Thank you in advance,

Matt

 

[RaDiKaL_]

Not sure if memtest would stress the CPU that much to get it to 65ºC, get into Windows and monitor your CPU temp, if its high at idle its very likely to be the reason of your shutdowns. Once it gets some usage it must be going beyond its thermal limit triggering its shutdown for protection.

If that's the problem, open your laptop to clean all dust inside and apply new thermal paste on the CPU.

 

[Suv_Chuck]

I just blew the laptop out and was running memtest. Was running at 50ishC plugged in, and it just shut off on test 7. Pretty sure that rules out heat as a problem, and I've only got a single stick of ram...

 

[Suv_Chuck]

Quick update: Threw some older ram into the thing and it quit memtest again! I'm really at a loss as to what's going on now. It was running at 58C, which I expected because this ram wasn't DDR3L like the last stick I had. It did run longer with this ram, but it only made it to test 9...

 

[Suv_Chuck]

Just checked the idle temp and it was 40c. It shut off at 55c. Intel rated this cpu for 100c maximum, so it definitely isn't heat.

 

[RaDiKaL_]

Just to discard every possibility, try with the laptop plugged in but with the battery out. It could be some issue in the battery leading to a preventive shutdown.

Other than that it could be some mobo's capacitor or similar component failing.