Computer starts, shuts down, and then repeats

KooKas · 10-25-2009, 06:36 AM

I've realised the cause of the explosion in the other computer, and it is simply down to extremely dodgy wiring in the room it was in. All of my computers that have ever broken in this house have broken because they were in that room and a surge or spike caused damage - broken memory sticks, power supplies, motherboards. And now another computer seems to be dead.

When I turn it on, it runs for about 10 seconds, and then shuts down. Nothing is displayed on the screen - perhaps the graphics card is damaged, and when the motherboard tries to start it up, some kind of fail-safe shuts it down? It seems that it shuts down at the point where the screen would normally receive a signal and change from being black to being a sort of pale grey colour.

I have plenty of spare graphics cards, so I'll probably try those in the place of the current one. I don't think my motherboard has an on-board graphics card - there's no VGA slot on the motherboard, just on the graphics card.

Infact, I've got a few spare of most computer parts, except a 650W power supply, which means that if it is the power supply that has failed, I won't have anything to try in its place - my computer needs atleast 600W and all my spares are 450W or less.

There were some symptoms of a bad power supply leading up to this - the computer would freeze up alot yesterday and would need to be reset. But one time, it would not restart. Computers aren't the only things that are affected by the faulty wiring of that room. The light flickers, and my lamp would flicker alot before the bulb blew.

I did plug my computer into the 8-way surge protector, and the lamp, but it seems to have been able to break it anyway - even trying it in a room which is wired up much better, it does the same thing when turned on, until it's switched off via the power supply. The power supply this time isn't a particularly low quality brand - it's a Corsair TX-650W. Nothing in the computer is particularly low quality, except for perhaps the DVD drive - which isn't low quality, just slightly dated.

I'm hoping that it's just one cheap part that is broken. I don't think it's a damaged memory stick, because I thought of that already, and tried replacing the 2x1GB DDR2s with a single 1GB DDR2 from the computer that exploded (see my other thread - it didn't go up in flames or anything).

The rest of the computer is as follows:
ASUS M3N78 PRO
PALiT NVIDIA GTX275 896MB GDDR3
AMD PhenomX4 9950 BE 2.66GHz (4 CPUs)
2GB (2x1GB) DDR2 800MHz RAM (OCZ)

It'd be great if someone who has suffered a similar issue (or someone who just knows what it is) could share their experience and perhaps tell me what was broken for them so I can perhaps narrow down my tests a bit. By the way, there were no beeps from the motherboard (it doesn't normally beep on startup, I probably didn't bother to plug in the speaker, I can't remember :X ).

**Tyree** · 10-25-2009, 07:31 AM

The best thing to do at this time is a bench test.

1) Remove EVERYTHING from the case
2) Set the motherboard on a non conductive surface. The motherboard box is perfect for this. DO NOT PLACE THE MOTHERBOARD ON THE STATIC BAG! It can actually conduct electricity! We are going to try and assemble a running system outside of the case.
3) Install the CPU and heat sink. Intel Guide AMD Guide
4) Install 1 stick of RAM.
5) Install the video card and attach the power supply connection(s) to the card if your card needs it.
6) Connect the monitor to the video card.
7) Connect the power supply to the motherboard with both the 24pin main ATX Power connection and the separate 4 or 8 pin power connection.
8) Connect power to the power supply.
9) Do NOT connect ANYTHING else. Make sure you have the power connector on the CPU fan connected.
10) Use a small screwdriver to momentarily short the power switch connector on the motherboard. Consult your motherboard manual to find which two pins connect to your case's power switch. Then touch both pins with a screwdriver to complete the circuit and boot the system.

If all is well, it should power up and you should get a display. Then assemble the parts into the case and try again. If the system now fails to boot, you have a short in the case and need to recheck your motherboard standoffs.

If the system does not boot after this process, then you most likely have a faulty component. You'll need to swap parts, start with the power supply, until you determine what is defective.

10-25-2009, 06:36 AM	#1 (permalink)
KooKas Registered User Join Date: Oct 2008 Location: England, United Kingdom Posts: 14 OS: Windows XP	Computer starts, shuts down, and then repeats I've realised the cause of the explosion in the other computer, and it is simply down to extremely dodgy wiring in the room it was in. All of my computers that have ever broken in this house have broken because they were in that room and a surge or spike caused damage - broken memory sticks, power supplies, motherboards. And now another computer seems to be dead. When I turn it on, it runs for about 10 seconds, and then shuts down. Nothing is displayed on the screen - perhaps the graphics card is damaged, and when the motherboard tries to start it up, some kind of fail-safe shuts it down? It seems that it shuts down at the point where the screen would normally receive a signal and change from being black to being a sort of pale grey colour. I have plenty of spare graphics cards, so I'll probably try those in the place of the current one. I don't think my motherboard has an on-board graphics card - there's no VGA slot on the motherboard, just on the graphics card. Infact, I've got a few spare of most computer parts, except a 650W power supply, which means that if it is the power supply that has failed, I won't have anything to try in its place - my computer needs atleast 600W and all my spares are 450W or less. There were some symptoms of a bad power supply leading up to this - the computer would freeze up alot yesterday and would need to be reset. But one time, it would not restart. Computers aren't the only things that are affected by the faulty wiring of that room. The light flickers, and my lamp would flicker alot before the bulb blew. I did plug my computer into the 8-way surge protector, and the lamp, but it seems to have been able to break it anyway - even trying it in a room which is wired up much better, it does the same thing when turned on, until it's switched off via the power supply. The power supply this time isn't a particularly low quality brand - it's a Corsair TX-650W. Nothing in the computer is particularly low quality, except for perhaps the DVD drive - which isn't low quality, just slightly dated. I'm hoping that it's just one cheap part that is broken. I don't think it's a damaged memory stick, because I thought of that already, and tried replacing the 2x1GB DDR2s with a single 1GB DDR2 from the computer that exploded (see my other thread - it didn't go up in flames or anything). The rest of the computer is as follows: ASUS M3N78 PRO PALiT NVIDIA GTX275 896MB GDDR3 AMD PhenomX4 9950 BE 2.66GHz (4 CPUs) 2GB (2x1GB) DDR2 800MHz RAM (OCZ) It'd be great if someone who has suffered a similar issue (or someone who just knows what it is) could share their experience and perhaps tell me what was broken for them so I can perhaps narrow down my tests a bit. By the way, there were no beeps from the motherboard (it doesn't normally beep on startup, I probably didn't bother to plug in the speaker, I can't remember :X ). Last edited by KooKas; 10-25-2009 at 06:39 AM.

10-25-2009, 07:31 AM	#2 (permalink)
Tyree Mentor Hardware Team Join Date: May 2009 Location: Illinois Posts: 5,810 OS: XP Pro-7RC-Mandriva My System	Re: Computer starts, shuts down, and then repeats The best thing to do at this time is a bench test. 1) Remove EVERYTHING from the case 2) Set the motherboard on a non conductive surface. The motherboard box is perfect for this. DO NOT PLACE THE MOTHERBOARD ON THE STATIC BAG! It can actually conduct electricity! We are going to try and assemble a running system outside of the case. 3) Install the CPU and heat sink. Intel Guide AMD Guide 4) Install 1 stick of RAM. 5) Install the video card and attach the power supply connection(s) to the card if your card needs it. 6) Connect the monitor to the video card. 7) Connect the power supply to the motherboard with both the 24pin main ATX Power connection and the separate 4 or 8 pin power connection. 8) Connect power to the power supply. 9) Do NOT connect ANYTHING else. Make sure you have the power connector on the CPU fan connected. 10) Use a small screwdriver to momentarily short the power switch connector on the motherboard. Consult your motherboard manual to find which two pins connect to your case's power switch. Then touch both pins with a screwdriver to complete the circuit and boot the system. If all is well, it should power up and you should get a display. Then assemble the parts into the case and try again. If the system now fails to boot, you have a short in the case and need to recheck your motherboard standoffs. If the system does not boot after this process, then you most likely have a faulty component. You'll need to swap parts, start with the power supply, until you determine what is defective. __________________ Posting your PC specs will help us to help you quicker and more efficiently.