Problem Unexplained PC power tripping/System Initiated Power Down

Hello,

I have encountered a problem regarding the power to my PC, so here's some background information regarding my diagnosis and steps taken: (scroll down all the way to see my queries).

This computer has been running with this configuration for 8 months now.

When I switch on my PC, it runs for a little while, but once it enters the Windows Desktop, the whole computer completely powers down abruptly, and when I press the power button it will refuse to turn on (even after multiple times) unless I let it 'rest' for several hours.

This happened after I upgraded my NVIDIA graphics drivers for my Geforce GT 630 (which certainly isn't a powerful graphic card by any means, but more than enough for average gaming).

So, I thought the graphics drivers were the problem. However, somehow every time I started up the computer it just would not be able to enter the desktop without shutting down abruptly. When I tried entering safe mode (including the command prompt option) and 'Load last known good configuration', it would not even enter the Windows Desktop, and it would just hang at the scrolling bars screen (The OS is Windows Vista 32-bit EN-US).

Then, I decided that something must have gone wrong with the boot loader, and I loaded my Windows 7 System Repair disc. To my horror, I discovered that 500GB worth of data located in 2 folders in a 2TB disk had vanished. Thankfully, CHKDSK repaired the problem, and I also subsequently used CHKDSK to repair the boot partition. However...

...just as I was CHKDSKing another drive, the whole computer completely cut itself off again without warning. As a precaution to my data, I took 4 of my 5 hard disks offline by disconnecting their respective power cables, except for the system boot disk. I also thought that my current power configuration could have overloaded the power supply, so I took the trouble to reset the CMOS (literally plugging out the battery since there isn't a jumper on the motherboard like the older ones used to have), and also disconnected the RAM for 2 minutes.

Unfortunately, the problem didn't abate and now the power cuts off immediately when the Windows 7 System Repair Disc is being read (i.e. When the DVD drive spins up to read the disc). Furthermore, when I try to power up after the power failure, spark sounds (the 'piak piak' sounds) can be heard from inside the chassis when I attempt to switch it on (which is damn scary.)

So now, I really need to ask:
1) Should I still attempt to switch on the computer?
2) What exactly is causing the fault...? Is it actually the power supply being unable to supply the entire system, or is there a potential short circuit elsewhere?
If the power supply is the cause, please recommend me the appropriate power loading in watts and I will use my own discretion for branding on my next purchase.
3) What steps can I take from this point, other than those mentioned above?

Also, just posting a bit of info on the specs of the system, if you need to determine the loading to the power supply is adequate. (This computer is clearly nowhere near decent as many of you here... I know)
Motherboard: GIGABYTE EP45-UD3LR
http://www.gigabyte.com/products/product-page.aspx?pid=3286#ov
Power Supply: SeaSonic 700W Power Supply
RAM: 2x 2GB Corsair 1366 MHz
Audio: Onboard 7.1 ch Realtek HD Audio
3 system fans, 1 CPU fan connected on board

Peripherals:
Graphics: Geforce GT630
1x LG DVD-RAM Writer
5x Hard disk drives (normal IDE/SATA, no RAID or AHCI)
All disks are Seagate branded, in increasing order of capacity (40GB, 80GB, 160GB, 500GB, 2TB) (A fruit salad combination)
2x USB flash disks connected at boot
No other peripherals connected.

I am looking forward to some responses with regards to this issue. For now, I have kept the computer switched off, in case it's going to harm my data even more.

 

check your heatsink to make sure the cooling fan is working properly and the fins in the heatsink are not stopped up with dust bunnies restricting the flow of air....

 

That is common for a cpu fan not working....... or restricted air flow..

 

Sorry for the late reply!

Thank you very much for the replies, to address the posted issues one by one:

1) I don't have the resources to get a backup disc that can hold 2TB worth of unique data... I have taken the disks out of the computer for safekeeping in anti-static bags. If I really do end up losing data I am willing to accept the consequences.
2) Regarding domed capacitors, it doesn't look like there are any... the capacitors are the polymer type. (And if there really are, it's very difficult to see the difference between a flat top and domed capacitor. (Or are polymer capacitors immune to this condition?)
3) I can't even boot to safe mode, as mentioned earlier. Rather than the whole computer powering down, it will just hang at the start-up screen.
4) I am not going to bother doing a system restore, I will just use safe mode to access the system (once I can get the computer to stop dying on me!) and manually uninstall the beta driver, and replace it with the stock default driver which I was provided with.

My CPU fan appears to be spinning normally. Not whirring fast like how some overheated CPUs would cause the high fan speed symptom. Only thing I am a bit puzzled is that the CPU fan actually takes a longer time to spin up (i.e. All the other three system fans spin up first to steady speed, only then the CPU fan begins to spin. I am not surprised though.

I am also not sure what restricted air flow meant here, but my set up has two air/fan inlets (front and side); and one air/fan outlet (at the rear). The system temperature is about 35 degrees celsius and the CPU 57, so I don't really view this as a cause of concern. Nonetheless, correct me if I am wrong.

There was some dust in the heatsink, but it's pretty minimal compared to another PC I have serviced before. Even so, it's only at the top of the heat sink that I have cleaned, because I am still trying to figure out how to remove the CPU fan assembly. There could be the supposed 'dust bunnies' like you mentioned buried around the core of the heat sink, but until I figure out to properly remove the heat sink assembly it's gonna take a while. (EDIT: Looks like removing the entire cooling assembly is VERY troublesome, because I am most likely going to make a mess with the thermal paste, and I am not sure how much paste I need to re-apply upon reinstallation, which is pretty risky at this point.)

Once I have gotten to the core of the heatsink and get it cleaned I will try again. In the meantime, if there are any misconceptions in the proposal above please do correct it at your disposal. Also, I look forward to more responses on this issue from the other members.

Thanks for your patience.

 

Get a cheap replacement power supply and try that.
Have to start somewhere.

 

Sorry, it's been a while since I provided an update!

@2oldGeek I did manage to remove the heatsink (with a hell of a mess), but there was very little dust to clean up... Somehow this didn't really solve the problem. The whole computer still abruptly powers down after 20 minutes or so. Also, the spark sounds are increasing in intensity, which is quite scary.

@attar I am thinking of buying a replacement power supply but I would appreciate it if someone could calculate the approximate load of the system and give me a recommended wattage for the power supply I am going to buy. Is 700W loading sufficient for my system? Or do I need 1000W or even higher? :O

Until that problem can be answered I am going to disassemble and strip to a barebone my existing system, starting the computer with just a power supply, motherboard, a stick of RAM, some jumpers and a minus head screwdriver - hopefully this gets me somewhere.

I hope someone can offer me alternative advice here.... at least something helpful without me having to replace the whole computer.

 

Thanks for the helpful links.

I literally stripped the computer down to a barebone, that is:
Motherboard resting on an anti-static sheet;
The power supply, with AUX 12V connector to CPU and ATX connected to motherboard
1 CPU with its fan socket connected to the motherboard
1 RAM (DDR2 Corsair)

CMOS battery is removed, no other stuff (wires, peripherals connected)
Computer started manually by shorting pins;

End result? Computer still dies after running for 2 minutes.

So, is this most likely the problem of:
-Motherboard
-CPU
-Power supply?

I don't think this has got to do with anything of a loading issue, or does anyone here think there is some kind of short circuit going on...?

I am hopeful for some responses... thanks!

 

It appears that for the last 30 minutes I tried to get the system on, my computer won't even last more than 3 seconds... This is what happens:
Upon shorting the power pins:
Computer attempts to boot up; power to motherboard with all 6 phase LED lights on.
CPU fan does not spin, but computer dies 1 second after this. PSU fan spins down.
3 seconds later, computer attempts to boot up; power to motherboard with all 6 phase LED lights on.
This lasts for 1-2 seconds until it dies again. Spark sounds can be heard from the power supply.

Any attempts to short the power pins are fruitless, the computer will never start up.
Power needs to be turned off, RAM sticks removed and left to drain for 1 minute before attempting to power on again.
And the whole cycle repeats.

Is this symptomatic of improperly connected power cables?

I replaced the anti-static mat with a piece of cardboard, do you think this could have caused static build-up?
Also, is it possible to swop the connector heads of the 24 pin ATX power connector (i.e. Motherboard side connector is plugged into PSU and vice versa) or will it cause both the PSU and motherboard to blow?

 

Time for me...

1. PSU.. it's making crackling noises.. so swap for another to test..

2. motherboard.. likely a bad fet or switching/regulator in the startup circuitry.. (most likely a fet or regulator is passing too much current and getting hot - shutting down.. causing reboot until it overheats again..) Often a bad capacitor somewhere.. other option.. bad north or southbridge connections.. expanding once warm and cutting connection somewhere..

Solutions?.. swap out the psu for another known good one.. still same problem?.. check any boards connected to mobo.. i'e graphics card/soundcard etc..

failing that... how good are your electronics component level troubleshooting skills?

 

Huh? You mean the 24 pin psu connector? And I am pretty confused about the connecting the cpu fan to the system header instead of the cpu header... Isn't the CPU fan supposed to be plugged into the CPU_FAN plug rather than the SYS_FAN2/SYS_FAN1/PWR_FAN plugs?

@ps355528 I will need to find a replacement PSU first... should be able to dig up a 20 pin ATX power supply anywhere, but that means I can't connect my graphics card to it anymore... or else the PSU will overload and die too.

I haven't done any form of detailed diagnosis on the motherboard, so I can't tell if a fet/regulator is malfunctioning. Also, I can't really tell if the capacitors are domed, because they all seemed flat at the top, with natural curvature at the sides.

Hmm... I don't really have the tools to for electronics component level troubleshooting, and I am not sure how high a level I need to work... maybe you could give me an example? If you are talking about soldering and bridging wires with spliced end sheaths connected by the insulated bridge that perhaps I am averagely skilled. (I could get my dad to help me, since his hands and fingers are more nimble at this.)

Hopeful for your positive replies.

 

Ok, time for a bit more of an update.

After I managed to salvage a power supply from a fried motherboard (CPU overheated from failed CPU fan), I plugged it in and it managed to boot up smoothly (without any hard disks inserted and stuff). It appears that the PSU was at fault... when I plugged the existing 600W cpu into the "dead" computer, the system would fail to start up and it would produce even more spark/crackling sounds than ever before, so for now it has been isolated.

Now that I have booted it up I have new problems... the Windows Vista OS would not boot up in the sense that Windows would load, but would stop loading before it hit the 'Please wait... and Press CTRL-ALT-DEL to log on" screens. Instead, I am presented with a black screen and a white mouse pointer. I am not sure if there is any other thread in this forum pertaining to this issue, so I am looking it up first (although anyone can feel free to provide a thread link to speed up my search or propose a solution to me.)

Also, when I opened up the existing 600W PSU, I discovered s sh*t load of dust. Literally everywhere. I would be happy to start cleaning it, but:
1) Could dustballs that flood the power supply be behind the crackling sounds and causing it not to startup?
2) I have read about it somewhere that the power supply, when open, is a potentially lethal weapon... especially the mega-large capacitors which can really kill. On the assumption that I am not going to lift the PSU circuit board off its holder (i.e. not going into come into contact with any of the PCB pins sticking out, what other precautions should I take? Is it all right to use a vacuum cleaner with the brush extension to suck up the dust or should I use an old toothbrush to brush the dirt off manually?

Last of all, I am looking at an 2 month old price list that I took from my daily trips at that electronics and computer hobby mall... out of the following brands available, which brand of power supply would be best recommended? I am looking for a roughly 650W - 850W power rating based on the calculators I have used so far my TDP is between 355W and 595 W, so a power supply in that range translates to 60-80% respectively.
Brands I have shortlisted:

• Antec
• Cooler Master (The current brand of my ATX casing)
  
• Corsair
• Seasonic
• Siverstone
• ThermalTake
  
• Xigmatek

Out of this list I am considering between Cooler Master and Seasonic, but I am not too sure... at least 80 Plus Gold efficiency rating?

 

How does Seasonic Power Supplies compare to that of Cooler Master?

Also, should I open a new thread regarding my boot issue with Windows Vista? Can't really find a solution based on what I have researched so far...

 

Ok, I have resolved the Windows Vista boot issue... turns out it did have something to do with the $TxF (Transactional NTFS folder) but I didn't want to go through the trouble of repairing it via linux, so I just reflashed an older Norton Ghost image and it booted up. The silverstone power supply appears to be dead, so I am just going to replace it. It seems like I am ready to close this topic, nonetheless, but I do have one last question regarding modular power supplies.

Are all the modular connectors to the power supply the same across all brands? Or do I have to buy a completely new set of modular cables for the new power supply? After all, my older one is a Silverstone and the one I am intending to get is a Cooler Master one, so I would like to be sure about that. Also, it is possible to order spare standalone modular power supply cables (and the like?)

Hoping for some replies so that I can close this thread soon, thanks.