system failed to power on

Supermicro C2sea - motherboard - atx - i...
March 22, 2010 at 09:55:41
Specs: Microsoft Windows Vista Ultimate 64bit, 2.394 GHz / 2029 MB
I shut my PC down at night, and turn in on in the morning for the day. It is connected to a battery backup. I also turn off the battery backup. When I powered on the battery backup this morning, the PC power switch did not cause the PC to start up. I noticed that the LAN link light on the back of the PC that lights when the PC is getting power but isn't on, was off. Then I noticed a pulsing tone from the PC speakers and the access light on the memory card reader was pulsing at the same time as the PC speaker was emitting a tone. Plugging the PC directly into the wall outlet did not work. The monitor, cable modem, router etc powered up fine from the same UPS. The system has a Seasonic power supply, Core 2 Due E8600, 8GB Corsair Memory, 8600GT video card, Super Micro mother board, so it is not a cheap box. Any suggestions on what to swap out first?

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March 22, 2010 at 10:16:40
Try to swap psu.

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March 22, 2010 at 10:37:47
Failing power supplies are common and can cause your symptoms.
Check your PS.
They often partially work, fans and hard drives may spin, leds may come on, yet you may get no video and the mboard will not boot all the way.
See response 4 in this:

If it is failing, you can usually replace it with any decent standard sized standard ATX PS with the same capacity or greater.

Standard (PS/2) power supply size - 86mm high, 150mm wide, 140mm deep, or 3 3/8" h x 5 7/8" w x 5 1/2" d , or very close to that, though the depth can be more or less for some PSs.

Don't buy an el-cheapo PS.
See response 3 in this:

Your power supply must have at least the minumum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD ! )
If that info is not in the ad for the video card, you can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.

"8600GT video"
Minimum of a 350 Watt power supply.

If you're a gamer.....
In most if not all cases, the max capacity rating of the PS is an intermittant rating. It's recommended that you do not load your PS to any more that 80% of that rating if you are going to be using something that puts a constant load on it, such as playing a recent game for hours on end. In that case, you multiply the min capacity stated for the system with the particular video chipset on the card by 1.25 to find the min. capacity of the PS you should get.

"8600GT video"
Minimum of a 350 Watt power supply.
350 x 1.25 = Minimum of a 437.5 Watt power supply

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March 23, 2010 at 09:34:06
Thanks for the excellent responses. It turned out to be something very strange. After letting the system sit while I was at work all day, the system came backup just fine. I think the cause may have been related to my battery backup. In any case the system worked fine last night and this morning. What is the most strange is that the system did not power on when plugged directly into the wall instead of the battery backup. This just points out that it is sometimes good to take a break during trouble shooting and be sure to leave the system unplugged during the break.

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Related Solutions

March 23, 2010 at 11:46:13
Better power supplies have built in features that shut off the PS when an event is detected that might damage the power supply has occurred - when that's triggered, there is a built in delay - the PS will not start up for at least a few minutes, then it works fine, if the problem is not detected again.

E.g. Enermax PSs do that, for overvoltage, overcurrent, shorts.

If power spikes, power surges were caused by lightning strike on the AC power grid, that can get past any anti-surge /anti-spike protection you have.

People often don't realize they must protect everything from power spikes and surges - everything that plugs into the computer that plugs in to AC power one way or another - all AC connections, and all AC to DC adapters - AND the cable that connects you to the internet - the telephone line or coax cable - if your computer connects to a modem or combo router/modem by means of a network cable.
"It is connected to a battery backup"
UPSs have anti- surge and anti-spike protection, BUT they often don't have enough connections to protect everything that plugs into the computer.

I suspect there was some event that produced a power spike or surge, and either
- you didn't have everything protected from that, and the event triggered the protection built into the power supply
- or - you did have everything protected from that, but the event triggered the protection built into the power supply anyway.

My brother had an el-cheapo power supply fail when the AC circuit it was connected to tripped the circuit breaker, despite most of, if not all of, the things connected to his his computer being plugged into a decent anti-surge/spike device.

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