Power Supply Problem?

**Dunedin** · 09-17-2008, 05:39 AM

Hello everyone,

I built this machine last December. It has been running perfectly till last week when it started shutting down randomly. The shut downs became more frequent and now when you turn it on the power button just flashes on and off again. When you try the power button again it does not even flash on. If you leave it for a while it does flash on and off. It is dead!

That`s all I know as I built it for someone else and did not see it until today.

I have checked all the cables and wires and all seem OK.
It was not dirty inside.
I don`t think it could be overheating as there are 3 big fans in the case apart from the CPU fan. Having said that I don`t know if they were all working. If it was overheating which component is more likely to be damaged, mobo or CPU? How do I check for that?

My first thought was the Power Supply, but the problem is I have no way of testing it.
Does it sound like it might be the PSU?

Gigabyte GA-P35-DS4 (Socket 775) PCI-Express DDR2 Motherboard
Intel Core 2 Duo E6750 "LGA775 Conroe" 2.66GHz (1333FSB)
Western Digital Caviar SE16 500GB SATA-II 16MB Cache
OCZ 2GB (4x 1GB) PC2-6400C4 Dual Channel Platinum Revision 2 XTC Series DDR2
Thermaltake ToughPower 750W Modular Power Supply
XpertVision GeForce 8800 GT 512MB DDR3, PCI-E
Creative Sound Blaster X-Fi XtremeMusic 7.1 Sound Card
Samsung SH-S202JBEBN 20x DVD±RW x12 Ram IDE Dual Layer DVD-Writer

Thanks for any help

Banscare · 09-17-2008, 05:51 AM

I run into this problem all the time at work and I have to agree its a bit troublesome. Sometimes I might get a blip of power and a couple fan rotations but no steady life by any means. From my experience with this particular problem I found that 50% of the time it was the power supply but the other 50% of the time it was the motherboard and processor. It was never one or the other, but both mobo and cpu that were damaged. I hope this is not the case in your situation.

**Dunedin** · 09-17-2008, 03:30 PM

Thanks for the reply Banscare

I hope it is not both the mobo and CPU as well

I am borrowing a tester for the PSU tomorrow night so hopefully that will be a step forward.

If it turns out not to be the PSU, I just wish there was a way to know the state of the mobo and CPU.

.

Hack7 · 09-18-2008, 10:40 AM

I had a similar problem. I found out that one of the power connectors on one of my 120mm fan had somehow shorted. I would get a flash of power then nothing. I removed the fan and everything ran fine. I only found it because of removing things from the computer to try to isolate the problem. Maybe a bench test would help?

**Dunedin** · 09-18-2008, 03:55 PM

Thanks Hack7

Well, tonight I tested the PSU and I think it is dead. A friend who is an electronics engineer is going to double check this for me at the weekend using some other piece of equipment.

So fingers crossed!

.

**magnethead** · 09-18-2008, 09:04 PM

just short the green pin to any black wire on the 20/24 pin connector.

**Dunedin** · 09-19-2008, 04:18 AM

Thanks magnethead, much appreciated

I will try that too.

.

09-17-2008, 05:39 AM	#1 (permalink)
Dunedin Mentor Join Date: Jul 2007 Location: Over the Forth from Edinburgh, Scotland Posts: 3,600 OS: WinXP Pro/Windows7 RTM Ultimate	Power Supply Problem? Hello everyone, I built this machine last December. It has been running perfectly till last week when it started shutting down randomly. The shut downs became more frequent and now when you turn it on the power button just flashes on and off again. When you try the power button again it does not even flash on. If you leave it for a while it does flash on and off. It is dead! That`s all I know as I built it for someone else and did not see it until today. I have checked all the cables and wires and all seem OK. It was not dirty inside. I don`t think it could be overheating as there are 3 big fans in the case apart from the CPU fan. Having said that I don`t know if they were all working. If it was overheating which component is more likely to be damaged, mobo or CPU? How do I check for that? My first thought was the Power Supply, but the problem is I have no way of testing it. Does it sound like it might be the PSU? Gigabyte GA-P35-DS4 (Socket 775) PCI-Express DDR2 Motherboard Intel Core 2 Duo E6750 "LGA775 Conroe" 2.66GHz (1333FSB) Western Digital Caviar SE16 500GB SATA-II 16MB Cache OCZ 2GB (4x 1GB) PC2-6400C4 Dual Channel Platinum Revision 2 XTC Series DDR2 Thermaltake ToughPower 750W Modular Power Supply XpertVision GeForce 8800 GT 512MB DDR3, PCI-E Creative Sound Blaster X-Fi XtremeMusic 7.1 Sound Card Samsung SH-S202JBEBN 20x DVD±RW x12 Ram IDE Dual Layer DVD-Writer Thanks for any help __________________

09-17-2008, 05:51 AM	#2 (permalink)
Banscare Registered User Join Date: Jun 2008 Location: St John's NL Posts: 190 OS: XP Pro 64bit My System	Re: Power Supply Problem? I run into this problem all the time at work and I have to agree its a bit troublesome. Sometimes I might get a blip of power and a couple fan rotations but no steady life by any means. From my experience with this particular problem I found that 50% of the time it was the power supply but the other 50% of the time it was the motherboard and processor. It was never one or the other, but both mobo and cpu that were damaged. I hope this is not the case in your situation. __________________ Ban Computer Support Specialist (MCP, MCSE)

09-17-2008, 03:30 PM	#3 (permalink)
Dunedin Mentor Join Date: Jul 2007 Location: Over the Forth from Edinburgh, Scotland Posts: 3,600 OS: WinXP Pro/Windows7 RTM Ultimate	Re: Power Supply Problem? Thanks for the reply Banscare I hope it is not both the mobo and CPU as well I am borrowing a tester for the PSU tomorrow night so hopefully that will be a step forward. If it turns out not to be the PSU, I just wish there was a way to know the state of the mobo and CPU. . __________________

09-18-2008, 10:40 AM	#4 (permalink)
Hack7 Registered User Join Date: Jan 2008 Location: St. Louis Posts: 92 OS: XP pro	Re: Power Supply Problem? I had a similar problem. I found out that one of the power connectors on one of my 120mm fan had somehow shorted. I would get a flash of power then nothing. I removed the fan and everything ran fine. I only found it because of removing things from the computer to try to isolate the problem. Maybe a bench test would help?

09-18-2008, 03:55 PM	#5 (permalink)
Dunedin Mentor Join Date: Jul 2007 Location: Over the Forth from Edinburgh, Scotland Posts: 3,600 OS: WinXP Pro/Windows7 RTM Ultimate	Re: Power Supply Problem? Thanks Hack7 Well, tonight I tested the PSU and I think it is dead. A friend who is an electronics engineer is going to double check this for me at the weekend using some other piece of equipment. So fingers crossed! . __________________

09-18-2008, 09:04 PM	#6 (permalink)
magnethead Registered User Join Date: Mar 2006 Location: Texas, USA Posts: 3,570 OS: Vista ultimate 32bit My System Blog Entries: 3	Re: Power Supply Problem? just short the green pin to any black wire on the 20/24 pin connector. __________________ For proper support: what are you running? graphics, cpu, m/board, ram, PSU brand wattage PCI-E requires 26 amps at 12 volts. That's a 650W PSU. Power Supply Info and Selection . Info on thermal compounds & application . TEST PSU USING MULTI-METER . Bench Testing Your System

09-19-2008, 04:18 AM	#7 (permalink)
Dunedin Mentor Join Date: Jul 2007 Location: Over the Forth from Edinburgh, Scotland Posts: 3,600 OS: WinXP Pro/Windows7 RTM Ultimate	Re: Power Supply Problem? Thanks magnethead, much appreciated I will try that too. . __________________