New PSU, and computer won't boot.

[ravenscraft]

Hello, everyone. I've read some useful things here in the past, so I figured I'd sign up and ask you guys first to see if you have any clue what's going on. In the past couple weeks, I noticed my PSU fan making some nasty sounds, until it finally died a few days ago. (The fan, not the PSU.) I contemplated trying to replace the fan, but then decided I wanted to upgrade the PSU anyway to make room for a few higher-wattage components later on. I did things safely, all power off, static-free environment, etc. However, when I finally tried to power on the computer, I wouldn't get any signal to the monitor. The drives (including HD) all boot up normally. The light on the motherboard is on. The panel works fine. The fans on the graphics cards both turn on. But no signal to the monitor.

Figuring something must be wrong with the PSU, I put the old one back in. Same problem. I have since gone through and reseated every connector I can find, with no luck. Since even the old PSU isn't working, I must assume I have done something wrong, but I'm not sure what. Any ideas what I should do next?

Here are the stats--
ASUS P5N-E
XFX NVIDIA GEFORCE 8800GT (x2, in SLI)

Old PSU --
CoolerMaster RP-600-PCAR

New PSU --
Corsair CMPUSU-750TX

 

[nboy22]

Strip the computer down to the bare essentials for power.. by this I mean take off all drives, keep the CPU, RAM, and video card in and then make really sure that the power connector running to your power switch is on the board correctly.

Here's another tip, wire your reset button as your power button, that way you can make sure that it's not your power button that's malfunctioning (Mine did this and now the reset button is wired as the power button)

Try another case and hook up it's power switch to your motherboard also.

Sounds like one of three things. Bad switch/connection of the switch to the motherboard, Bad motherboard, or bad connection of power connectors to the motherboard.

 

[ravenscraft]

In my previous attempts, I disconnected all drives and only had power to the graphics card (removed one) and motherboard. Still no signal to the monitor. If the problem were the power switch, would anything at all turn on? Because the computer (or at least several components) does turn on, but then sends no signal. I did try swapping the reset / power switches, and got the same result.

I don't have an extra case to try its power switch, unfortunately. Posting this on a laptop.

 

[RadiclDreamer]

You can short the 2 pins that the power switch is connected to with a screwdriver and it will act the same as a power switch. If this turns the system on then the switch is bad, if not then you can safely assume the switch is not your problem. Also, check that the 20 and if applicable the 24 pin as well as any aux 4 pin connectors are secure on the motherboard. Barring all of this it seems like the board could be toast.

 

[ravenscraft]

It's looking more and more like the board is fried, as I feared. The switch is working properly, and I have reseated the motherboard power connectors multiple times with no luck. At least the components seem salvageable, and that board was relatively inexpensive anyway.

Well, in an effort to learn from my mistakes, anyone know what I might have done wrong? I'm not sure how I could have damaged the board, and there wasn't any power going to the system while I was working on it. I've replaced PSUs before with no problems. It would be less than ideal to replace the board, only to fry that one too, heh.

 

[nboy22]

Originally posted by: ravenscraft
It's looking more and more like the board is fried, as I feared. The switch is working properly, and I have reseated the motherboard power connectors multiple times with no luck. At least the components seem salvageable, and that board was relatively inexpensive anyway.

Well, in an effort to learn from my mistakes, anyone know what I might have done wrong? I'm not sure how I could have damaged the board, and there wasn't any power going to the system while I was working on it. I've replaced PSUs before with no problems. It would be less than ideal to replace the board, only to fry that one too, heh.

Well now that you mention that the power switch is working fine (I must have read the first post wrong) you probably have a motherboard problem. In fact, I'm 99% sure it's a motherboard problem because I've seen this before. Just take a step back and look at the motherboard, there's so many little things that could go wrong!

One of the best things you can do is just make sure you're not working on carpet when installing, or a static-attracting surface. Wear a static strip at all times or make sure your hand is touched to the case. Also, make sure you have all the motherboard standoffs correctly in place. These things happen, in fact just last February my gigabyte motherboard just died on me, I didn't do anything to it.

My friend's Acer computer had the same problem as yours, except his got a bios virus or something of that sort to where you wouldn't see anything on the screen at all. I asked him if he saw any weird messages on his screen the last time it was on and he said it said something about, "Bios update complete, restarting computer." That's a good indication that he had some sort of bios virus. But as I said before, motherboards go out easy and I have even had it happen to me without even touching it.

 

[KGB]

Have you tried resetting / clearing the CMOS via the onboard jumper?

If not, try it.