Laptop mysteriously shuts off (while idle or nearly so)

[GrandSpleen]

Hi,
I've got a mysterious little problem here. My laptop recently has begun to shut itself off, suddenly (not shut down, just immediately power off). After a couple of seconds, it powers back on and starts to boot up-- at which point it is liable to power off again. If I hit the power switch myself and let it stay off, give it a few seconds and then power it up again manually, it has so far recovered and will boot up and function normally.

It looks the same as if the thing is overheating, and the laptop is using its emerging shutoff to prevent damage to the CPU. The problem is, this is occurring when the computer is idle, or engaged in minimally demanding activities (maybe 2 web browsers open).

The laptop has a history of overheating while playing games, and I've seen it shut itself off under those conditions. After cleaning out dust and starting to monitor the temperature while idle and under load, I haven't seen any problems with shutting off under load. When it shuts off now, the fan is going at a very low speed. I've been monitoring idle temperatures over the last couple of days, and I'm getting around 50 C, which seems high but as I understand it, this is normal for a i7 quad core kind of thing. My system specs are below, at the bottom of this post. When idle, the CPU usage is between 0 and 10%, and while using a browser I'm seeing up to near 20% when a new page is being loaded.

I can't reproduce the error voluntarily, so if I brought it in to a shop I am not sure they would be able to help. Hard to fix what you can't see for yourself. Has anyone encountered this kind of thing before? I'm hoping to get a couple of things here: ideas about a likely culprit causing the shutdowns, and/or get pointed to some tool that I can use to monitor the system to help figure out what is happening right before a shutdown. Any ideas?

Thanks very much for any help, and for reading this far. My system specs are below:

Base PC was an MSI 16F2.

Intel Core i7-2670QM, 2.2-3.1GHz, (32nm, 6MB L3 cache)
nVidia GeForce GTX 580M 2,048MB
12GB DDR3 1333MHz Dual Channel Memory
750GB 7200RPM 16MB Cache Buffer (Serial-ATA II 3GB/s) hard drive
Onboard audio
15.6" screen, 1900x1080 matte type
Windows 7 Home Premium 64-bit
15.57"x10.54", 5.85lbs

edit: I should also mention that this is happening while the computer is plugged in. The battery is also in (and with 97% charge according to the system tray), so if there were a burp in the electricity from the outlet it shouldn't cause a shutdown.

 

[Burpo]

Random shuts offs are usually heat related or bad caps on the motherboard. Bad caps can wreak havoc with voltages, or cause an undervolted (slow) CPU fan at idle, that leads to excessive heat and shutdown. I hate to say it but it's probably time for a dis-assembly & inspection of the capacitors near the CPU socket.

Symptoms
The most common method of identifying capacitors which have failed because of bad electrolyte is visual inspection. Such a capacitor will show one or more of these symptoms:

* Bulging of the vent on the top of the capacitor
* Sitting crooked on the circuit board as the bottom rubber plug is pushed out
* Electrolyte (a crusty brown substance) leaked onto the motherboard from the base of the capacitor
* Venting from the top of the capacitor, visible as rust-like brown deposits, or a visible hole in the vent

As the capacitor ages, its capacitance decreases while its equivalent series resistance (ESR) increases. When this happens, the capacitors no longer adequately serve their purpose of filtering the direct current voltages on the motherboard, and system instability results. Some common symptoms are:

* Not turning on all the time; having to hit reset or try turning the computer on again
* Instabilities (hangs, BSODs, kernel panics, etc.), especially when symptoms get progressively more frequent over time
* Vcore or other system voltages fluctuating or going out of range, possibly with an increase in CPU temperature as the core voltage rises
* Memory errors, especially ones that get more frequent with time
* Spontaneous reboots
* In case of onboard video cards, unstable image in some video modes
* Failing to complete the POST, or rebooting before it is completed
* Never starting the POST; fans spin but the system appears dead

 

[GrandSpleen]

Thanks for the reply. I now have something to investigate. I've disassembled this thing partially once before, when I wanted to clean the dust out as thoroughly as possible. Sounds like I may need to go a bit further.

And if the capacitors are bad, is that just "wait until the computer dies," or is that something that can be repaired? Definitely out of my skillset, but if it can be fixed by a pro that might save me the cost of a whole new system..

Also, the laptop is from xoticpc.com, I selected the components and they put it together. There's no branding on the case.

 

[Burpo]

If it's a case of cheap Taiwan caps failing (not saying it is), it'll probably need a motherboard. I scrapped an HP last week with the same problem. A good electronics shop that refurbs motherboards can replace the caps, but that can cost as much as a motherboard..

 

[VirtualLarry]

I had someone come to me with a similar issue, on an i7QM laptop too. His battery was at 0%, and sometimes charging and not charging. Temps were around 50C with CoreTemp.

He was having random shutdowns.

I got the laptop, pulled the battery, and was running on AC for an hour, and I didn't get any shutdowns. I even wiggled the AC wire and jack a bit, just to see if perhaps they were loose.

So I ordered a new battery. I hope that fixes it.

 

[GrandSpleen]

New development.

I opened the laptop to see if I could visualize bad capacitors, but it required more disassembly than I was comfortable performing on my own, so I couldn't answer that question. I just removed the top, took the fan out to dust it off (as I had done before), then put it back together.

After I put the laptop back together, it stopped functioning entirely. I don't know if there's a connection between opening it and the failure, but I think the hard drive has been corrupted somehow. Could a faulty hard drive lead to the random shutdowns I was experiencing earlier?

I've got a SATA to Usb tool, so I took the hard drive out and tried connecting it to four different PCs (all Windows 7 except one, which was Vista). They recognized the drive but couldn't read its data, and read it as unformatted. I even opened it up in Partition Commander. There, it read as 'damaged' and all of the partitioning tools were not usable. I tried one of those free data recovery programs, but after about an hour of 'deep scanning' it didn't pull up anything useful, just some system files and a random assortment of pictures from my browser cache.

I have a backup but it's a few months old, so I was hoping to at least pull some of the more recent data off, but I haven't been able to read the drive anywhere. I'm out of ideas, so I'll try to reinstall Windows and see if that helps. I'd like to know if I should expect this again though... it might just be better to buy a new drive. But if the capacitors were causing the random shutdowns, and not the drive, maybe it's just time for a new system altogether...

Questions, questions...

 

[pw257008]

Can you boot off a usb stick?

 

[GrandSpleen]

I tried booting from the hard drive in question while it was connected, via the USB/Sata adapter, to a second laptop. This didn't work, the computer just went black for some seconds and then went into its own hard drive's OS.

I haven't tried booting via USB on the original laptop, yet. Maybe I can try that this evening after work.

 

[GrandSpleen]

Well, it was not the hard drive. My SATA to USB converter was not working, I think. I put the hard drive inside of my wife's laptop and it booted fine. I backed up all my important data then and there.

The laptop itself is still dead, though. I don't know what the issue is. It looks like it starts booting to Windows, loads for 2 or 3 seconds, then it flashes a blue screen with a wall of text for about a millisecond, then reboots. Infinite loop.

 

[GrandSpleen]

aaand, figured out the boot loop. When I was taking out the fan to clean it off the other day, I accidentally unplugged the wrong cable. I replaced it, but I think it caused a reset in BIOS settings. the SATA setting in BIOS had been switched to RAID, and as a result the computer didn't boot properly. I switched it to AHCI and that resolved.

So now I'm just back to the random unpredictable crashing.