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

[Speed]

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

[peterb]

Yes - certainly sounds like a PSU problem - card works in another system, known good card doesn't work in that one... Only way to tell for certain is with a known good psu.

Some mobo bioses do allow you to set the compute topower up automatically, which might explain why it started itself.

Only other thing could it could be is the mobo, but that is unlikely. Possibly a power spike when the power went off took it down. (Yes I know you said you have a surge protector - but IMHO they really don't cut it. The only thing is that if it one that 'gurantees' your kit, you may be able to make a claim - but not without some hassle.

[Speed]

Yes I agree, it's possible when the power went down it took out the PSU.

Like you say it could be the motherboard, but that wouldn't be such a problem as I was considering an upgrade shortly.

I guess I'm going to have to purchase a new power supply!

[peterb]

And a UPS?

[Speed]

If I could afford one I would!

Thanks for your help btw!

Hmm... Corsair HX620W Modular or Corsair TX750W?

[Speed]

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.

[Speed]

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!

[Speed]

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?

[peterb]

Yes, my money would be on the mobo - whether it was failing anyway or whether plugging in the dodgy old PSU again did something is a matter of speculation (and I'm sure you are wondereing that too!) - probably not.

There is also a (very slight) risk that the mobo might have damaged the new PSU - but If the replacement was a good quality branded one, that is very unlikely.

The initial boot process is quite simple - a timer hol;ds the CPU reset line low until all the Power rails have stabilised, the reset line is then relaesed at the CPU jumps to an address in the bios - and the boot continues. If you are getting a continuous reboot, then either the bios is corrupt or the timer isn't properly releasing the CPU reset line.

As for the power burtton - its behavious is usually governed by the BIOS configuration, although you have cleared the CMOS, so that should be back to the default setting.

If you were thinking of upgrading anyway - now is probably the time to do it.

(And think again about a UPS - about £60 from Scan - look on it as an insurance ploicy!)

[Speed]

Yes, my money would be on the mobo - whether it was failing anyway or whether plugging in the dodgy old PSU again did something is a matter of speculation (and I'm sure you are wondereing that too!) - probably not.

There is also a (very slight) risk that the mobo might have damaged the new PSU - but If the replacement was a good quality branded one, that is very unlikely.

Yeah I really don't like not knowing but some things are beyond our control. The PSU is a good make, Corsair VX450, so it should be fine and it's under warranty if it's not.

(And think again about a UPS - about £60 from Scan - look on it as an insurance ploicy!)

I will, although can you really get anything decent enough for that sort of money? I'm guessing (according to what I've read on Wiki) that I will want a "on-line UPS"?

[peterb]

Some here

http://www.scan.co.uk/Index.aspx?NT=1-0-45-84-0

I use one of the Liebert Powersure (well 3 in total - I think mine are about 400VA) cheap and cheerful - only snag you might find is that the shutdown interface is a serial connection. You may prefer one with a USB interface (its only for auto shutdown if power is off for any length of time) Mine hold up for about 3 minutes - but will protect against brownouts and surges.

[Speed]

Yeah I did spot them, but I don't know the first thing about selecting a suitable one.

Are even the cheap ones "on line" versions that manage the output? Ideally I would want one that provides protection against spikes, surges and the like.

There are three distinct types of UPS: off-line, line-interactive and double conversion (also called on-line). An off-line UPS remains idle until a power failure occurs, and then switches from utility power to its own power source, almost instantaneously. An on-line UPS continuously powers the protected load from its energy reserves stored in a lead-acid battery or flywheel, while simultaneously replenishing the reserves from the AC power. It also provides protection against all common power problems, and for this reason it is also known as a power conditioner and a line conditioner.

Source: http://en.wikipedia.org/wiki/Uninter...e_power_supply

My next concern would be how they would handle a high end Pc, they do seem to all come with overload warnings, just need to work out what sort of rating I would need.

[peterb]

On-line is beste of the three, but expensive - line interactive is fine for a home PC/server set up. 700VA would be fine for most PCs. (equates roughly to 560W - 600W)