enjay Posted December 14, 2007 Posted December 14, 2007 One of our PCs got turned off rather brutally today (i.e. mains power killed) and now it won't turn on again. Pressing the power button causes the Num/Caps/Scroll Lock lights to flash and the fans start spinning so the PSU would appear to be okay, but the PC doesn't even start the POST. Is there anything I can do for this beyond write it off and buy a new board?
tech_guy Posted December 14, 2007 Posted December 14, 2007 Have you tried another known good HDD in it?
enjay Posted December 14, 2007 Author Posted December 14, 2007 try resetting the bios on it. Done that - well, I had it unplugged and held the power button in for a while, which resets the BIOS doesn't it, or does that just remove any residual charge from the board?
strawberry Posted December 14, 2007 Posted December 14, 2007 I've never known to do it that way. theres usually a jumper on the mobo to do it, otherwise take out the system battery, disconnect power and leave it untill monday morning.
Guest kerrymoralee9280 Posted December 14, 2007 Posted December 14, 2007 Have you tried another known good HDD in it? Even without a HDD in it, it would reach POST.
Michael Posted December 14, 2007 Posted December 14, 2007 You're describing the symptoms of a dead motherboard (by the sounds of things). Removing the motherboard battery will have little effect. The battery is there to save BIOS information and has nothing to do with any charge left on the board itself. To properly remove charge from the board, you need to disconnect the PSU. @tech_guy - A computer can POST without a hard drive. You'll just receive an error no OS can be found.
Heebeejeebee Posted December 14, 2007 Posted December 14, 2007 I've had a couple of these lately (crappy MSI boards). Only solution was to swap the mobo out. HBJB
SYNACK Posted December 14, 2007 Posted December 14, 2007 If you want a definitive answer as to what cooked itself you should get a POST tester card. It plugs into the PCI bus and reads the diagnostic signals of the busted motherboard and can tell you at what point post fails. http://www.pc-diagnostics.com/pc_diagnostics_tools/flippost_isa_pci_bus.shtml This will definitively rule out the RAM or CPU.
StewartKnight Posted December 15, 2007 Posted December 15, 2007 try another PSU, it could be the 12volt rail I'd remove all components, except the CPU and start adding ram hdd etc to see if it posted.
tech_guy Posted December 15, 2007 Posted December 15, 2007 We've had duff hdds stopping the successful completion of the post of some of our Dell PCs but that's Dell for you...
K.C.Leblanc Posted December 15, 2007 Posted December 15, 2007 Sounds like a mobo failure to me. However I would try another PSU.
EduTech Posted December 15, 2007 Posted December 15, 2007 Yup i agree from what ur sayin sounds like a mobo Failure.. replace the motherboard should be oki.. i have had systems that dnt POST change the board everythings sound but on the other hand.. like a few other people are saying its not always the mobo that causes the sytem not to POST.. i would say the best way round it is to do what StewartKinight was saying Hope u get it sorted regards James
Oops_my_bad Posted December 17, 2007 Posted December 17, 2007 Im not sure the power loss would have blown it, more likely to be when the power came back up again
mrtechsystems Posted December 17, 2007 Posted December 17, 2007 Basic check on a motherboard you normally get a green light to say there is power to the board
enjay Posted January 22, 2008 Author Posted January 22, 2008 Okay, this is really bugging me now - even out of the case, I can't get either the old or new motherboards to boot! At one point, the old one booted and gave a two-tone error sound (kind of like a Police car, twice) - sadly this error tone isn't listed among the POST beeps on Intel's web site. The tests which I have done to date are: swap RAM, processor, power supply (by running two PCs side-by-side, stretching the wires from one case to the other), test the CPU and RAM in a different PC, remove the board from the case completely, turn it on then immediately remove the power switch jumpers. What test have I missed out? I will try pretty much anything now, however random it might seem! Can someone please tell me what on God's green earth is wrong with this damn PC?!?!
chalkwellstu Posted January 22, 2008 Posted January 22, 2008 Okay, this is really bugging me now - even out of the case, I can't get either the old or new motherboards to boot! At one point, the old one booted and gave a two-tone error sound (kind of like a Police car, twice) - sadly this error tone isn't listed among the POST beeps on Intel's web site. The tests which I have done to date are: swap RAM, processor, power supply (by running two PCs side-by-side, stretching the wires from one case to the other), test the CPU and RAM in a different PC, remove the board from the case completely, turn it on then immediately remove the power switch jumpers. What test have I missed out? I will try pretty much anything now, however random it might seem! Can someone please tell me what on God's green earth is wrong with this damn PC?!?! sounds like it's broke seriously i've had this Nick and it turned out to be the power supply changed it and all ok.
unclebunny Posted January 22, 2008 Posted January 22, 2008 The siren beep sounds to me like a CPU temperature warning, so it may be worth making sure its properly seated, the fan's powered and the heat sink's secure. My first thought was that the memory was shorting, but if you've tried both some old and new memory sticks in the board then that's not likely. You could try taking the RAM out completely and trying to at least cause memory beeps. If you get no beeps then its something serious on the board, if you do get beeps then its something to do with the RAM. I'd say to strip the board down to the bare essentials, and use a known good power supply, processor and single RAM stick. If it still fails to even POST, just take off the components, find out which ones work, and chuck the board itself.
contink Posted January 22, 2008 Posted January 22, 2008 In the past I've assumed it's the motherboard but I've since learned that even though the PSU may have appeared to have survived, one or more of the power rails has not gone without damage. As a rule of thumb in something like this a PSU replacement is pretty much mandated otherwise you run the risk of blowing yet another board with bad power. That said, sounds like you've already gone that route and at a guess the fact that the PSU survived enough is an indicator that it passed on a lot of damage to the other components from RAM on down to HD and motherboard.. I'd ditch it and start over.
enjay Posted January 23, 2008 Author Posted January 23, 2008 @unclebenny - CPU temperature is possible, as the CPU fan wasn't seated correctly but that wouldn't kick in the very second I turn it on, would it? Surely it would take it a little while to get hot enough for it to be a problem?? @contink - sadly, I think you're right. I'm wondering if the PSU is damaged but still able to supply enough power to turn on, and I've gone and stuffed board no.2 as well....
rhyds Posted January 23, 2008 Posted January 23, 2008 On my 1st day I had a similar issue, PC wouldn't fire and none of the POST beep codes it gave were the same, I decided to try the PSU before declaring anything else dead and lo and behold, she fired
bandgeekmafia78 Posted January 23, 2008 Posted January 23, 2008 We had a similar problem last week.... We ordered in a new motherboard and the problem didn't go away. Turned out it was actually the PSU, which was strange. Give it a try!
contink Posted January 23, 2008 Posted January 23, 2008 @contink - sadly, I think you're right. I'm wondering if the PSU is damaged but still able to supply enough power to turn on, and I've gone and stuffed board no.2 as well.... Could be worse... My father once famously stuffed 3 motherboards in quick succession because he got "angry" and stopped thinking straight. I, in turn, learned that "I told you so" still got you a clip round the ear even though I was right... or as my father later said when apologising, especially for being right! Anyways, as a result I always change the PSU first after a spike to ensure he doesn't get on the blower to return the favour
rusty155 Posted January 23, 2008 Posted January 23, 2008 Have you taken a Voltmeter to the PSU to check everything is reading ok? - Darn sight quicker than replacing it just to check. http://www.clunk.org.uk/forums/guides/253-voltage-measuring-guide.html
markwatkins Posted January 23, 2008 Posted January 23, 2008 Which make is it, we have had a series of problems with older RMs never have found out what causes it but the board appears to blow PSUs
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