Solved

(capt) PC powers down unexpectedly - not a heat issue...

Posted on 2014-11-15
25
212 Views
Last Modified: 2014-12-29
This has me stumped.

Desktop PC single Processor AMD Phenom, clean and no dust, air cooled, with 8GB Ram DDR2 and Win7.

This switches off randomly, just as if it has a heat issue. All heat sensors are connected and hardware probes show that there is no unusual rise in temperature at the time of shut off. Sometimes shut off happens at boot, sometime after 10 minutes idle time, sometimes after 1 hour of constant use.

This has been scanned for Virus and Rootkits and is clean.

Symptoms are the same every time, no blue screen, no freeze, no warning of any kind. Just power off. The only difference here can be that 4 out of 10 times you cannot power back on with the switch, you have to switch power supply off and on again.

The PC runs forever in BIOS mode, e.g. booting into BIOS only. It also seems to 'behave' in Safe Mode. But it does not in Windows.

I have completely reinstalled Windows after full HDD format and the problem still persists. So it is not a rogue driver that has crept in or some 3rd party software.

As I said, the symptoms are like overheating but it is not, it does not appear to be a driver issue, so it must be hardware and standard windows function combined, but I don't know where to start diagnosing this.

Anyone any ideas what to do next?

Thanks
capt.
0
Comment
Question by:captain
  • 10
  • 6
  • 5
  • +3
25 Comments
 
LVL 53

Expert Comment

by:McKnife
ID: 40444460
Hi.

Let's use the correct terms. Is it a shutdown, a bluescreen followed by a reboot or does it just "blackout", that is behave as if you have pulled the power cord?
0
 
LVL 87

Assisted Solution

by:rindi
rindi earned 125 total points
ID: 40444462
Try another PSU, maybe the one you have has defective electrolytic capacitors or just can't output enough power. Also the mainboard could have defective electrolytic caps, so check it visually for signs of them cracking, leaking or bulging. Also try changing the CMOS battery.

It is still possible that the CPU overheats, remove the heatsink, very thoroughly clean both the CPU's and it's surface from any old thermal transfer paste or pads, then apply a very small drop of fresh thermal transfer paste and firmly and properly reattach the heatsink. Thermal shutdowns often happen very fast and don't get recorded. Besides that the thermal sensor might not output correct readings.
0
 
LVL 30

Author Comment

by:captain
ID: 40444529
>>Correct terms

Not sure what you mean, but as I said:
Symptoms are the same every time, no blue screen, no freeze, no warning of any kind. Just power off.

I will check the PSU Monday, will need to find one first :)

I already clean and reseated heatsink, new transfer paste and checked for any discolouration on the CPU. The caps on the mainboard looked pretty new and undisturbed but I will check these again when swapping PSUs.
0
 
LVL 53

Assisted Solution

by:McKnife
McKnife earned 25 total points
ID: 40444541
Sorry, I tried to read carefully (or so I thought)... :(
Ok, if it's a poweroff, normally the power supply is the cause.
0
 
LVL 30

Author Comment

by:captain
ID: 40444877
No worries.

So I suppose the best course of action is to get a suitable power supply and start from there.

btw. I now had the PC for 6 hours on in safe mode and no shutdown.
0
 
LVL 91

Accepted Solution

by:
nobus earned 175 total points
ID: 40445329
can you post the model of pc, or motherboard, along with a couple of specs?  ram, disk setup and size, and connected devices?
you can find most info if you navigate to : start>allprograms>Acessories>system tools>system information
look in hardware for details

any of these can be the cause - so my suggestion is to test with a minimum setup, as described here :
http://www.experts-exchange.com/Hardware/Components/Motherboards/A_1945.html                  (Short-overview-of-how-to-troubleshoot-bad-hardware-when-a-pc-does-not-post)
0
 
LVL 6

Assisted Solution

by:Rob G
Rob G earned 75 total points
ID: 40450910
I agree with rindi, sounds like a bad power supply..
Or you have a power strip, surge protector that is failing..
What else do you have plugged into the strip?


(Wall)----------Cord-----(printer)(PC)(Monitor)(speakers)

What happens if you plug the system directly into the wall.. with the monitor, and nothing else?
0
 
LVL 30

Author Comment

by:captain
ID: 40450936
None of the other items that hang on the same strip go off.

I am  now waiting for a new powersupply, I will isolate that when I receive it and plug straight into the wall.
0
 
LVL 5

Assisted Solution

by:Aaron
Aaron earned 100 total points
ID: 40453676
I believe this to be the power supply as well. It should be noted that computers use a more delicate flow of electricity usually handled by the power supply but if the wall outlet is providing to erratic flow of electric the power supply wont be able to handle it or overtime can fail. It might be worth it to get a nicer surge protector or a cheap battery backup. If the problem persists after getting a new power supply you should try the battery backup so the flow is uninturupted. Also be sure to get a power supply that can handle the PC needs especially if you have a powerful GPU and CPU as well as ddr2 ram (which is about twice the voltage of ddr3) and some MoBos take a lot too. I think you made the right choice with getting a new power supply it's always good to have an extra if that turns out to not be the problem.
0
 
LVL 30

Author Comment

by:captain
ID: 40453806
Thanks, I should have it by Friday latest :)
0
 
LVL 91

Expert Comment

by:nobus
ID: 40454424
another PS is a good test; but in the mean time, you can troubleshoot following the article i posted above
0
 
LVL 30

Author Comment

by:captain
ID: 40454865
Hi nobus

oops sorry in the flurry of notifs I did not see your post.

Hardware Info
Processor      
AMD Phenom(tm) 9950 Quad-Core Processor, 2600 Mhz, 4 Core(s), 4 Logical Processor(s)

MB
BIOS Version/Date      Phoenix Technologies, LTD ASUS CROSSHAIR II FORMULA ACPI BIOS Revision 2607, 11/06/2010

GPU
NVIDIA GeForce 8800 GTX

LAN
Marvell Yukon 88E8056 PCI-E Gigabit Ethernet Controller

GPU & LAN both on IRQ 16      

RAM
DDR2 only 4Gb Crucial Memory installed...not 8

HDD
WD 500Gb x2 in NVIDIA onboard RAID 0+1

Something I noticed just now typing this is that the mouse hangs every few minutes, not sure if dodgy cable or something else, may swap that too..

capt.
0
How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

 
LVL 5

Expert Comment

by:Aaron
ID: 40455026
Looking at that I would suggest at least a 600 watt power supply though personally I would go with a 650 or 700... Assuming you have a few fans and might want to add more in the future. I know that recomended might not be that high but I always like a buffer. Other experts insist that 500 watts is the most you will ever need but I have never had a power supply issue in my custom builds and I believe that using 650+ watts is a part of that reason.
0
 
LVL 91

Expert Comment

by:nobus
ID: 40455271
before buying a PS - calculate how much power you need here :
http://extreme.outervision.com/psucalculatorlite.jsp

often you need a lot less than you think - and allow a margin of 50 W

there is a bios upgrade -2702  http://www.asus.com/Motherboards/CROSSHAIR_II_FORMULA/HelpDesk_Download/

you can also install the latest drivers from that page
0
 
LVL 30

Author Comment

by:captain
ID: 40455896
Thanks, calculations show:
Recommended PSU Wattage: 590w
Minimum PSU Wattage: 540w
0
 
LVL 5

Expert Comment

by:Aaron
ID: 40455928
Yeah so 650 would be just about perfect it's like a magic number ha ha
0
 
LVL 91

Expert Comment

by:nobus
ID: 40456763
you included fans, usb devices etc also?
then yes a 650 W is a good choice
unless you foresee other devices coming ?
0
 
LVL 5

Expert Comment

by:Aaron
ID: 40457205
If you want to do ATI Crossfire or SLI 2 cards (assuming you have the mobo slots) make sure that you get a certified ready PSU for crossfire/sli (SLI in this case). Generally you would want a 750 watt+ and make sure it has two 6 or 8 port connectors if needed for the GPUs.
0
 
LVL 30

Author Comment

by:captain
ID: 40457690
you included fans, usb devices etc also?

Yes, I also included USB Scanner. :) To be honest, the costs for the extra Watts are not excessive, so  I may as well opt for 750W.

The funny thing is that they vary from $25 to $100. What level of expense is sensible? Cheap may not last that long or is not an SLI compliant PSU but is $100 necessary?
0
 
LVL 5

Expert Comment

by:Aaron
ID: 40457753
I would say 40-60$ gets you about what you need. I would stay away from any under 40 and over 80 it better be 700+ watts and gold cert.

Here is one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817182264

And it is crossfire/sli capable so if you want to expand later.
0
 
LVL 30

Author Comment

by:captain
ID: 40468687
So I have been sitting here for the best part of a week and the PC is stable as it can be. The only issue is that it is stable with the old PSU...

I am baffled.

Naturally I am loathed to swap things for swapping sake. So I will continue monitoring this and swap when needed.

I think I can close this out as the consensus is PSU.
0
 
LVL 91

Expert Comment

by:nobus
ID: 40468762
it is the first device that comes to mind; but it can be other devices as well
0
 
LVL 30

Author Comment

by:captain
ID: 40493708
almost 2 weeks on, and I still have not swapped PSUs as no fault has occurred.

I will see what happens over the weekend under heavy use and either close or report back.
0
 
LVL 91

Expert Comment

by:nobus
ID: 40493997
are all devices connected?  if not, do so
as a test, you can update all drivers allso
0
 
LVL 30

Author Comment

by:captain
ID: 40521830
Lots of use over Christmas, no problems at all. I kept the power supply for spares but have decided to not mess with the setup unless the problem emerges again.

Thanks for all the help. Will split for new year.
0

Featured Post

Free Trending Threat Insights Every Day

Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

Join & Write a Comment

I don't know if many of you have made the great mistake of using the Cisco Thin Client model with the management software VXC. If you have then you are probably more then familiar with the incredibly clunky interface, the numerous work arounds, and …
The recent Microsoft changes on update philosophy for Windows pre-10 and their impact on existing WSUS implementations.
This Micro Tutorial will teach you how to the overview of Microsoft Security Essentials. This is a free anti-virus software that guards your PC against viruses, spyware, worms, and other malicious software. This will be demonstrated using Windows…
This Micro Tutorial will give you a basic overview of Windows DVD Burner through its features and interface. This will be demonstrated using Windows 7 operating system.

744 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now