scarygood48

Hi,

I am new to this whole hardware thing, but I think I might have a bad PSU. Here is my problem:

I was doing 3D modeling in Maya and all of a sudden my PC just shut off. I tried turning it back on using the button on the front of the case but nothing happened. I unplugged it, plugged it back in, and it went on for a second or two and then it shut off again. I've ben looking around online for a solution and it seems the most common answer is that this is a bad PSU. Others say it could be a fried MB or a short. My question is if this is a bad PSU how is the PC still able to turn on for a few seconds before shutting down? Also, how is the MB always getting power (green light on MB is always on as long as the PC is plugged in) if this is a bad PSU? Again I am new to troubleshooting these hardware problems, so please use noob terminology.

mattlock

There are different voltages rails supplied by the PSU. It only takes one insufficient rail to cause a system not to POST. The symptoms range from, no sign of life at all to system instability and random reboots.


The strangest one I've seen was a switching issue with a PSU, where you could hit the power button and nothing would happen at all. Then a few minutes later the system would start as if someone just hit the power button. This would only occur if the system had been off for a couple a days.

dai

check your tempretures it sounds more like a heat problem a underpowered or failing psu can add to the problem
check the computer fans and h/sinks are clear of dust
post your system specs including the power supply details
http://www.softpedia.com/progDownloa...oad-29890.html

scarygood48

OK, I just went and bought a new PSU and installed it and it is doing the same thing (starting for a few seconds and shutting down). Here are the specs:

ASUS P5N-E SLI NForce 650I SLI MB
OLD PSU: Xion 500 Watt 2.2 ATX
New PSU: Antec 500 Watt 2.01 ATX
XFX Extreme NVidia G8800 GTX 768M

I have checked before and all my fans are working and there is no dust in anything (this PC is 3 months old). All the fans are still working with the new PSU. I have never installed a PSU before though and just went on intuition for where everything connects. Also, the Xion PSU had a SLI ready connector that went into my graphics card but the Antec doesn't...can someone explain to me what this is and if I need it or not.

mattlock

You need the PCI-E connector going to the video card, and with that video card I would be running no less than a quality 650w PSU. I shocked that the system ran for 3 month with the choke hold it had on that Xion PSU.

Checkout our Power Supply Selection thread. You are running a Power Desktop and you'll find a list of recommended PSUs toward the bottom of the page.

scarygood48

Well I had CyberPowerPC build this for me, I would have thought that they would mention to me that this build requires more wattage. I finally got through to their tech support after a week of trying and with them I took out the memory and the video card and tried turning the PC on and it did the same thing. So with that the tech support guy said it was most likely the MB, which was my hunch. So any ideas why the MB would be fried after only 3 months? I didn't notice any fried capacitors or anything out of the ordinary on it. Cyber Power Pc is going to replace the MB and see if this is the problem. My next question is, since I am new to this stuff should I send the PC in for them to install it or do you think I would be able to install it myself, possibly with some help from you guys? Maybe someone could direct me to a good tutorial on installing a new MB? The reasons I am hesitant to send it in is because I need this PC back ASAP for this upcoming semester and the cost of shipment. However, I am afraid that if the new MB doesn't fix this problem I will have to send it in to them anyways to troubleshoot it. Any suggestions? You guys think that the new MB will most likely fix the problem? I'll definitely be putting a 750w PSU once I get this all set up.

dai

they are easy to fit you just need to take it slow and double check everything
check you hold your warranty if you fit it yourself
http://www.hardwaresecrets.com/article/145

scarygood48

OK so I talked to tech support again and he said that the Wattage doesn't matter because if that was the problem then the PC wouldnt have ever turned on in the first place. So can you please explain to me how the PSU's wattage affects the MB and why I need more?

mattlock

If you're system is under powered it will boot, but as more strain is put on the PSU it begins to overheat and becomes less and less efficient. The results can range from system instability, poor frame rates in games, random shut downs, all the way to total melt down.

That XION 500 is rated in perfect lab conditions @ 25°c and is about 70% efficient. Put it a realworld environment, and it has no chance of hitting 500w.

The 8800GTX is a pretty power hungry card, pulling around 120w alone.

scarygood48

Thanks....so what would you recommend I replace it with? My teacher told me I needed at least 700w, but I dont know what a good brand is for power supplies.

1 g0t 0wn3d

An antec trio 650 watt would be perfect as would a 750 pc power and cooling

http://www.newegg.com/Product/Produc...82E16817371001

http://www.newegg.com/Product/Produc...82E16817703009

Keep in mind that the pc power and cooling is well....large in size

mattlock

Click the link below and scroll down to "Recommended brand names and models in listed categories" any of the ones listed under Power Desktop is the suitable for your system.

BTW, you're teacher is a wise man.

Here's a few good deals after rebate.

http://microcenter.com/single_produc...uct_id=0244447
http://microcenter.com/single_produc...uct_id=0244447
http://www.newegg.com/Product/Produc...82E16817171024