Help! OC'd system won't turn on

[wongnog]

Guys the nightmare of my life has come true. Today I woke up and my computer won't turn on! I had just finished a 24 hr round of StressPrime 95 on my system after finding my cpu and ram OC ceiling. So I decided to turn on Q-Fan on my Asus mobo and turn one of my outtake fans on low in order to reduce noise. I was doing some video encoding and downloading overnight (temps were reaching around 54°C, which was about 3° higher than with Q-Fan off and my fan on full), but when I woke up the power switch on my computer did nothing! I openned up the case, tried reseating the PWR SWITCH jumper, cleared the CMOS battery, even openned up the front panel to make sure the physical power switch connections were okay. Nada! And yes I have power to my system because there's a little green light on my motherboard chassis that lights up when it gets power. Have I done something horribly wrong, like fry the CPU? Or has my PSU gone kaput? Here's my system specs:

mobo: Asus A8N SLI-Premium
CPU: Opteron 165 (OC'd to 286 fsb x 9)
Ram: 2x512mb OCZ Platinum rev2 (on 5/6 divider, mem timings 3-7-3-3)
PSU: Antec SmartPower 2.0 (edit: 450W, comes with Antec Sonata II case)
video card: evga 7800 GT CO

Hope someone can help! Thanks

 

[myocardia]

Chances are very good that you're one of the >50% of the people who've bought that case and didn't replace the psu, and it has failed on them. Especially since you were overclocking, plus using a 7800GT.

But, before you go buy another psu, are you sure that you reset the BIOS correctly? First, unplug the computer while it's running, to discharge all of the capacitors in both the psu and on the motherboard. Then, don't plug it back in, and leave the battery out for at least 15 minutes. If it still won't start after that, you'll need another psu. If it does start, start saving your money for a good psu.

 

[wongnog]

Good suggestion, I'll give it a try when I Get home. If I do need a new PSU, do you have any good suggestions? Optimally I'd like one that a) doesn't break the bank; and b) doesn't sound like a wind tunnel. Thanks for your help!

 

[Nil Einne]

What power switch jumper?

Anyway the first thing to do would be to try a very long clear of the CMOS. Disconnect the battery and put the clear CMOS jumper in to position and leave it like this for an hour or so.

If it still doesn't work the next thing to try is to disconnect everything (except perhaps the CPU although I like to re-seat it eventually). Then add (CPU+HSF if you removed it) one stick of RAM, the video card, and all power to mobo and try and boot. Don't add anything else. You dont even really need a keyboard.

If it still doesn't work remove the mobo from the case (and take of the CPU if you haven't already) and try again. While you PSU may have died, a 450W Antec should be more then enough for your system. Some case PSUs are crap but Antec PSUs are fine

Also since you seem a bit uncertain about the powerswitch don't use it. Justs short the two power pins.

 

[myocardia]

Actually, that psu is a POS. Nearly everyone who's used it has had it fail on them, almost always in less than a year. And he was just saying that he even tried disconnecting the connector that makes the connection between the front panel power switch and the motherboard.

 

[Markfw]

Yup, I had one go on me, even though it works on a mobo that doesn;t require a 24 pin connector (very strange), but yes the TP2 450 is a POS IMO. I have 10 Antec PSU's in the house and this is one of the newest ones, and the only one to fail.

 

[wongnog]

Changing topic slightly to PSU recommendations... A friend said that OCZ is good, and I noticed my local store has rebates on a couple of their PSUs. Do you guys like them? Which would you chose among these?

OCZ GameXStream Power Supply (SLI Ready) 600W
OCZ GameXStream Power Supply (SLI Ready) 700W
OCZ ModStream Power Supply 520W
OCZ PowerStream Power Supply (SLI Ready) 520W

 

[myocardia]

Out of those psu's, I'd take the Powerstream 520. It doesn't really have enough power for SLI or Xfire, with high-end cards, though.

 

[Markfw]

Seasonic, Fortron, and the King, PC Power and Cooling. I still like Antec, its just the 450 TP2 that seems to be a bad egg.

 

[wongnog]

Okay so I followed some suggestions from here and other boards. I unplugged PSU from mains, and moved the AC power cord to plug directly from a wall outlet (not through a power bar). I then used a paper clip to short the green and black wires on the 20-pin connector, and the power supply fan powered up. I did notice that the PSU was emitting a faint, high pitched whine when all its connectors were unplugged from my computer, but it went away as soon as I plugged in the 20-pin connector. Anyway, I plugged the mains back onto the board, but the system would still not turn on. I wonder of the power button on my Antec Sonata II case is the problem, but after taking off the front cover I don't see any noticeable problems.

Next step I'm going to try a 380W power supply from an Antec Sonata I case and see if that works. Please let me know if you guys have any more ideas! Thanks.

 

[wongnog]

Okay! Well I grabbed the 380W Antec SmartPower from an existing computer, and plugged in the 4-pin and 20-pin connectors to my system. Supplied the AC power, turned the computer on, and everything powered up. So I think it's my PSU that is at fault!

 

[mauri]

I had this same problem with my Antec TPII 550W. It just didn't power up one morning. I had the green led on at the mobo, so It had some power coming to it, but still it didn't power itself up. And I had the same high pitched whine coming from the PSU, all the time power was plugged.

Luckily I still had some warranty left for it. The tech support from the store I bought it from told me that they have had many of these kind of Antec PSU failures lately (past year or so). I got a NEO HE as a replacement, and all worked after that, so it is definately the PSU.

edit: typos.

 

[wongnog]

I considered an Antec NEO HE but luckily read some posts on ncix reporting problems with that psu and the Asus A8N series motherboards. So I picked up a OCZ GameXStream Power Supply (SLI Ready) 600W instead. It's probably a bit more powerful than I need, but the pricepoint wasn't higher than other less powerful models and I figure it will last me longer and prepare me for future upgrades. At first I was disappointed it didn't have modular cables, but then I read that modular cables are just a "fad" and will result in less stable connections because the cables can come out of their connections... Ehhh anyway I'm happy with my new PSU and still have some warranty left on the TP2 450W so I'll RMA it and either keep the replacement around as a backup PSU or sell it. Thanks again for all your help guys!