Bad Power Supply? or Power Switch?

August 8, 2006 at 07:00:14
Specs: Windows XP Professional, AMD 3200XP/1024MB

Ok, I built my pc a couple of years ago. Just recently my pc would not shut down. If I select shutdown through the O/S it would restart and if I hold down the power button it will restart (power button is set to soft-off in bios) I made sure all of the wake-on options are disabled in the bios. I thought it might be a bad power switch so I switched the power button wire and the reset button wire to see if that would fix the problem. Other than the restarting instead of shut down it ran fine. After switching the wires, now the pc turns on when I switch the master power switch on the back of the pc to On without pressing the power button and the pc will not boot up, everything comes on, the fans, lights, hard drive but it wont't even get to the post screen. It's as if it's revving up and down and then when it finally gets to the point that the monitor should click on it seems to lose power for a second and then starts up again. It still does this after I switched the wires back to where they are supposed to go.

I have an Asus A7N8X2.0 Deluxe Motherboard
1GB Ram (2X512MB Duel Channel)
80 Gig Hard drive
Radeon X 800XL Video card
Antec Smart Power 2.0 500watt Power supply

I used to have an Antec 430watt power supply that lasted about 1.5 years. When that died I upgraded to the 500watt power supply, this one is only 6 months old. I have 5 case fans (2 front, 2 back, one in door. My CPU is an AMD XP2500 overclocked to an XP3200. I can't believe this would be too much for this power supply.

I just wanted some feedback before I go and drop another $100 on my third power supply. If that's the problem any suggestions on a better brand of power supply or if u think it is the power switch I would appreciate. Thanks.

P.S. I tired unplugging the video card and case fans and cd drives, turned on pc and still same problem.

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August 8, 2006 at 07:18:24

What caused it to die? What were the symptoms from your first PS?

"Other than the restarting instead of shut down it ran fine"
Restarting when pressing the power button?
If so, then there's nothing wrong with the power switch.

"this one is only 6 months old"
You should get a warranty for that

If you can't fix it, blow it up and deny that you saw anything.

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August 8, 2006 at 08:13:48

"I thought it might be a bad power switch so I switched the power button wire and the reset button wire to see if that would fix the problem."

Correct me if I am wrong but I think that the power switch closes the circuit and keeps it closed until you press it again and hold it down for about 30 seconds. The reset switch OPENS the circuit until you release it then the circuit goes back to its previous state, usually closed.

So, I don't think your experiment helped determine if your power switch is working .... or not. The way to test that is to try a different switch ... which may mean try a new case.

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August 8, 2006 at 09:00:21

I thought that the power switch and reset switch were both normally open (But I could be wrong as I never ohmed them out). Anyways, you can also short the power pins momentarily with tweezers to see if it's your switch instead of changing cases

If you can't fix it, blow it up and deny that you saw anything.

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Related Solutions

August 8, 2006 at 10:03:02

Thanks for the responses. I had read that if you suspect the power button has gone bad you can just switch the power and reset wires so that the reset button now will turn the computer on and off. When I hold down the power button the computer is supposed to shut down after 4 seconds but it doesn't, it restarts. When the first power supply went bad my pc would freeze anytime anything with 2d/3d graphics would come on the screen, or any type of load on the power supply. This gradually got worse and during boot-up I got the "system failed VGA test". First I thought it was the video card because when I took out my Radeon 9800pro and put in my old Radeon 9000 it worked with no problems but I eventually found out that the video card was not the problem because when I got my x 800xl it did not work. It turned out that because the radeon 9000 did not require a power cable from the power supply and the 9800 and x 800xl do, I guess the 9000 does not put much of a load on the power supply. After I put in the antec 430 watt power supply all of the video cards worked. The antec 500watt power supply is still under warranty but let me guess that I can't return it to CompUSA and I probably have to mail it to ANTEC INC. and get a different power supply in about 6 - 8 weeks. Screw that I would rather buy a different brand then wait that long. (hardcore gamer :) I just wanted to make sure it was the power supply and not something like a fried motherboard before I go and spend more money on another power supply. Thanks again...

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August 8, 2006 at 11:12:12

The power & reset switches are similar to a doorbell button...pressing the button makes contact (closes the circuit), releasing the button opens the circuit. There's really not too much that can go wrong with them.

Antec PSUs have a 3 yr warranty. You may even be able to RMA the 430W unit (if you still have it).

Troubleshoot your problem as best you can before buying a new PSU. Personally, I wouldn't spend money on a new one if I knew I could get a new one thru the RMA process.

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August 8, 2006 at 12:38:11

I know what your saying but I can't not have my computer for 6-8 weeks, i'm assuming that's how long it would take. I would rather just never buy an Antec product again.

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August 8, 2006 at 12:54:27

In addition to a bad power switch, a bad MOBO or short between the MOBO and the case could explain your computer's behavior.

Can you test the MOBO outside of the case?

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August 9, 2006 at 03:42:09

Hi, Power switch on an ATX is a momentary switch. Only closed when you are holding it down. MB has a circuit that passes the switch closure on to the power supply. If it causes anything at all to happen the switch is OK.

Luck, Jim

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August 9, 2006 at 10:58:53

Well it's fixed. I said the hell with it and went out and bought a ThermalTake 500watt powersupply and installed it and my computer is back up and running. Thanks everybody for your responses. I also bought a multimeter so I can test my power supplies to verify if they are bad or not. Now if I can just figure out how to use the damn thing. Thanks again.

P.S. Well I guess I can send my old PSU back to Antec now and get a back-up replacement PSU for when this one goes bad :)

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