Power Cut Causing Booting Problems... Suggestions?!?

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Hi Guys,

Well today of all days (My Day Off!) I wake up to a power cut, quite a large one (area wise) from what I've been told, but it didn't last too long. Once the power was back one I went around checking the computers, all of which were off at the time of both the power going off and coming on. All of the computers worked fine apart from one, my main setup! Typical! (Well that's not the word I used but you get the picture! ;))

I did in fact unplug all my kit including this computer from the wall while the power cut was still happening as a precaution, but it didn't help. The computer itself and everything else connected to it is running through a surge protector, but I thought better safe than sorry!

So once the power comes back on I plugged the computer back in and it bursts into life, which I thought was odd as I didn't touch the power button. Either way all the fans are running but no monitor picture, so I check the cables and I can't see anything wrong so I took the side panel off and both of the X1800XTs red warning lights are solid, the ones by the PCI-E power socket. I guess this implies that there is a problem with the power supply, as it's not supplying the power the card needs even though the PCI-E 6 pin power connector is plugged in.

The only way I could turn the computer off is either the rocker power switch on the power supply or pulling the plug. Both the reset button and power switch on the case didn't do anything. So I thought I better test the graphics card, plugged it into another system and it works fine. The warning lights did flash for a second on boot up, but I expect that's normal. I put the X300SE that was in the second system in to my main setup and still no joy. I've also stripped out the system by removing anything that wasn't needed for boot up, hard drives, sound cards etc and that didn't help. I've also cleared the bios but that didn't help either.

So am I right in assuming another Antec powersupply has bit the dust? Anything else left to try? Any advice or suggestions would be much appreciated before I go out and buy another (Non-Antec!!) PSU!

Thanks,

Mark
 
More developments.... new power supply arrived about an hour ago, hooked it up, plugged it in and the system came on again on it's own. It does boot to BIOS now which is good news, I've not tried Windows yet but I doubt it would be a problem. I hooked up the original power supply and the system doesn't start, there is also a worrying burning smell from the power supply unit so I won't be doing that again!

The main issue now is the power button, it doesn't turn the system off anymore, if I just press it the system resets and if I hold it in, the system just goes blank until I release and it resets.

I've disconnected all the power switch, reset switch, speaker etc connections from the motherboard and it still turns on once the power supply is given power. I've also cleared the CMOS which didn't help, I'm guessing this points towards a motherboard issue, which isn't a problem as it will most likely be replaced during the next upgrade.

Has anyone had similar problems with power switches? Just want to confirm what I've worked out through trial and error.
 
Never come across anything like this before. Do you have another motherboard you can try at all? Perhaps even ask a friend?

Certainly seems very strange. I would be tempted to make sure the power switches, restarts etc are plugged in properly onto the motherboard.
 
It is pretty strange yes, like you I've never seen it before.

I've now tried the system with two different power supplies, both pretty new and I have the same problem. It's either the switch itself or the motherboard as far as I can see, my money would be on the motherboard.

I have tried the switch connectors both ways on the motherboard, but they should have worked as they were, they have not been moved in about a year. It's not a huge issue, I do have spare motherboards, I have infact got a total of three Asus A8N-E's. The hassle of changing switching one puts me off. I will however do it when I upgrade my main system as there will be one spare!

Thanks for the reply!
 
Try disconnecting the switch wires from the motherboard, does it power up now?

Some bios have the facility to 'auto-power on' after a power failure. Are you sure this isn't enabled?
 
Hi Malcolm,

I did indeed try this, removed all connectors from the motherboard including both the reset and power switches. It still started up once power was given to the powersupply!

As for the "auto-power on" feature, I'll take a look in the manual but I can't say I've seen anything in the Bios before.

I'm now on said Pc in Windows and the shutdown function also reboots the computer!
 
I've just gone through the BIOS and found the following under APM Configuration:

Restore on AC Power Loss & PWR Button < 4 Second

However both are set correctly, I even enabled Restore on AC Power Loss and disabled it again after a reboot, but it didn't do anything.
 
Well things have gone downhill this morning. Last night I had the system up and running in Windows and aside from the previously mentioned problem with the power switch everything was fine. It started ok this morning and I had various websites up before getting in the shower, however once I was out the system had rebooted and was stuck in what I can only describe as a reset loop. It kept trying to post, but couldn't, nothing was displayed on the screen and it just kept resetting. I turned it off, unplugged the hard drives (as I'm sure spinning up like that wasn't doing them any good), did a CMOS reset and tried again, but still had the same problem.

I've got a feeling that the motherboard was damaged either by the power supply or the power cut.

Any suggestions anyone? Looks like I may have to bring my upgrade forward!
 
RAM

Could be the RAM, try removing multiple sticks and starting with a single stick. Try as many individually as you have.

It sounds like you had a power surge when you reconnected, and its blown through your psu and onto the board. Just what its taken out along the way seems to be the issue now.

The strange startup exhibits a behaviour I last saw about 4 years back, and it turned out to be the HDD LED was the wrong way round .... That took me many hours to figure out. I know you mentioned you already disco'd all the cabling, but that one is sometimes so innocuous its easy to overlook.
 
Thanks for the suggestions, this is what I've tried just now:

  • Removed second stick
  • Changed single stick with known working stick
  • Changed graphics card with known working card
  • Re-seated all of the motherboards power connectors
  • Removed all of the connectors to do with power switches, speaker, reset switches from the motherboard. They were disconnected before as my Lian Li case has a connector in the cable that goes to the case so you can remove the motherboard with the motherboard tray without disconnecting all of the connections individually. I thought it might be shorting something.

Unfortunately none of this helped, it just sits there and reboots itself time and time again. You can tell it's doing this as the fans have a slight pause when it does and you can hear the DVD drive checking for a disc.

From what we know: The ram, power supply, graphics are all working, so from what I can see that just leaves the CPU and Motherboard. My money would be on the motherboard.

Anyone got any more suggestions?
 
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