8760w shuts off suddenly

[zappazapper]

I've had this problem for a while.

Computer shuts down suddenly, like no Windows shutdown, just power off, then restarts, and as soon as I sign in to Windows, shuts off again, restarts, so on and so on.

I thought maybe it was a heatsink issue.  Using the maintenance manual I carefully removed the CPU and GPU heatsinks, cleaned them, reapplied heatsink paste, reassembled the computer and for the first couple of days it was fine but starting last night it started shutting down again.

This is a fresh install of Windows 10 Home on a new GPT/UEFI SSD.  I have 2 other HDDs in the laptop.  All updates installed, all outstanding drivers in the Device Manager installed.  Bios updated to latest (64?).

I have a docking station (HSTNN-I11X), but it makes no difference whether it's connected or not.  Use dual monitor, but again, makes no difference if the second monitor is connected.  Use a FireWire audio interface, but again, makes no difference of its connected or not.  If I disconnect everything including the mouse and the power, it still shuts down.

[iomare]

Hi,

It does kind of point towards an overheating issue since it worked for a couple of days after you replaced thermal paste material.

Did you also replace the thermal pads? Did you reseat the graphics card? Is the fan running well, it might not be efficient after some years.

Have you tried only with battery, and only with ac adapter. If you enter BIOS at startup, does it stay on without shutdown?

Have you tried with different ac adapter?

Let me know,

David

[zappazapper]

hi David...  thanks for responding...

ok, a brief update...  i've replaced the thermal paste and now also the thermal pads in the GPU...  yes, i reseated the GPU as it was removed to clean (the old thermal pads were an absolute mess)...  i used OCCT to monitor the heat sensors and everything is running much cooler...  as far as i can tell the fan is running fine and i cleaned the fins of the heatsinks with compressed air before reinstalling them...

as far as i can tell, whether it was before or not, heat is not an issue...

the laptop is fine on battery power but shuts down immediately when using the AC adapter, at least in windows 10, just after entering my login PIN...  it doesn't shut down when in the BIOS...  i have tried a different AC adapter and it still shuts down...  the other adapter is just a cheap one...  also, it makes no difference if the laptop is plugged into the docking station or not...  if the power cable is plugged in, either directly to the laptop or into the connected docking station, it shuts down within seconds...  the laptop charges just fine when it is off...  also, the adapter is not even remotely warm, and it's been plugged in the same place for months...

a friend suggested maybe a deep clean with denatured alcohol...  the same friend also said that if it was him, he'd just cut his losses...  he thinks it's a short on the motherboard, which would be next to impossible to fix myself, and prohibitively expensive to get it repaired by a professional...  i have yet to research the cost of a replacement motherboard...

if you have any other questions, i'm happy to answer...  thanks for your interest in helping me solve my issue...