Has blown PSU killed my motherboard?

By whitefort
Nov 2, 2006
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  1. Hi. This is my first post, and I'm in utter despair here...

    A few months ago, I had the proudest moment of my life when I built my own PC. It's been working perfectly, until a few nights ago when the Power supply failed with a strong smell of burning (actually set off a smoke alarn).

    I've just got a replacement and connected it up, and the PC is still dead. Here's what happens:

    When I press the power switch, the 'power on' light lights, the case fan begins to turn, and the CPU fan begins to turn - but all this happens for only about half a second, and then everything goes totally dead again. None of this last long enough for anything to appear on the monitor, and there are no POST beeps.

    I'm at a complete loss what to do. Does this sound as if my motherboard has been destroyed? Or are there any other possibilities? If the PSU *has* killed the motherboard, I presume this means the motherboard warranty won't cover it?

    I'd be really grateful for any help.

    Thanks,

    John
  2. Baltan

    Baltan Newcomer, in training Posts: 250

    What kind of power supply did you have? Did you have a crapy generic one or a really cheap one? If you did then it most probebly sound that your mobo is destroyed.

    Get this the same thing happened to me about two weeks ago, but i can still get on my comnputer. The things that dont work on my mobo is the sound and usb ports. So i have decided to get a new processor , Memory, motherboard and power supply.

    Sounds to me that you motherboard is destroyed and you will have to get a new mobo.

    What are your system specs?

    Baltan
  3. AtK SpAdE

    AtK SpAdE TechSpot Chancellor Posts: 1,846

    First off, I will let you know, PSUs go out. It just happens.(especially with lower end PSUs) Do not let this turn you off of PC building! That said,

    When PSUs go, they often take other parts with them. Motherboards being one of the most frequent. What you really need to do is.

    1. Try and test the PSU in another PC if possible. You have to make sure that the new PSU is in working order before replacing things.
    2. Your CPU could of went. This is extremely hard to tell, as there is no sure way to test it short of putting it in another rig.

    The way it turns on then quickly turns off sounds like a short to me. The leads me to point to the mobo.

    I hope this helps, and I am sure other members will have more suggestions

    Good Luck

    Sean
  4. whitefort

    whitefort Newcomer, in training Topic Starter

    Thanks, guys. It was a pretty expensive PSU - an Antec 500w Smartpower 2.0.

    The motherboard is (was?) a Gigabyte GA-8i945P-G-RH, with an Intel Pentium D.

    I don't think these could be described as crappy components. This is a total nightmare for me, and I'm starting to think I must have been mad to think I could ever make a working PC in the first place!

    John
  5. Baltan

    Baltan Newcomer, in training Posts: 250


    I dont think you could be described as mad. Just unlucky. What website did you order the parts from or wher did you get the computer?.

    I think that it is very likely that your motherboard is damged but that is my opinion you will have to wait and see what other people say.

    Baltan
  6. Nodsu

    Nodsu Newcomer, in training Posts: 9,431

    The short doesn't have to be in the motherboard.

    Try with only the mobo connected and then start adding components. CPU, RAM, vid card, etc.

    BTW, my old PC died last week - PSU blew. The only working components left were one RAM stick (out of 3) and the radio tuner card. Mobo, CPU, rest of RAM, vid card, NIC, sound, HD, DVD-RW - all dead :(
  7. whitefort

    whitefort Newcomer, in training Topic Starter

    Hi, Baltan. I'm in the UK. I ordered the parts from Dabs.com.

    I'm guessing that the situation must be one of the following:

    1. The replacement power supply is faulty.
    2. The motherboard is wrecked.
    3. The CPU is wrecked.
    4. The motherboard AND CPU are wrecked.

    My problem is that I'm a retired guy on a tiny pension. I can't afford to buy nearly a whole set of other components just to find out which part isn't working. Realistically, I'm thinking I'll have to swallow my pride and take the whole thing to a repair shop. Which will also be costly, but probably less so.

    I'm depressed!

    John
  8. nickslick74

    nickslick74 Newcomer, in training Posts: 883

    Check into your warranty info for all of your stuff. You never know, some of it may able to be replaced under warranty.
  9. Tedster

    Tedster Techspot old timer..... Posts: 10,074   +13

    rma each part. Most companies will return it to you if it is not bad, or send you a replacement if it is. In any case it is only a few bucks for shipping rather than buying a whole new component.
  10. whitefort

    whitefort Newcomer, in training Topic Starter

    Thanks, guys. Sorry for my earlier whining posts - it's just that when I put in the new PSU I thought everything would work and I'd have a PC again. It's all been a bit of a shock. I'm going to follow your suggestions, but I guess it will be a while before I have anything to report. I'll let you know how it goes.

    Thanks again.

    John
  11. whitefort

    whitefort Newcomer, in training Topic Starter

    Hi guys, I'm back. To recap, my PC worked great for 3-4 months, then the PSU failed with a burning smell that set off the household smoke detector.

    I replaced the PSU, but the PC wouldn't power up. I suspected a trashed motherboard. Now my semi-helpful friend at the PC shop claims to have tested the motherboard with another PSU, and says it's OK and that this PSU is probably an out-of-the-box dud. To be honest, though, I kinda got the feeling he just didn't want to know. He spent about 5 minutes on it, and refused to charge me - and didn't offer any further help.

    My questions - If I get yet another PSU (expensive!), is there any danger that there *IS* something wrong with the motherboard, and it will just blow the PSU again? Can this happen?

    Also (and here's where I *really* show how little I know), If I wanted to switch to a different brand of PSU, I'm wondering if I'll have problems - my PC has 2 SATA hard drives, one SATA DVD drive, and a graphics card that needs to connect to the PSU. My Antec PSU came with all the necessary connections, and there was no problem. But I see that most drives only come with one SATA connection. Is this going to create difficulties, or is it easy enough to connect all the SATA drives up so they use the one PSU connector?

    Oh, and one last thing. My PSU is a 500W. The books I used when building my PC said that this would be more than enough - but the PC shop guy says I should think about trying a 550. Doesn't 500 sound like enough for my setup?


    Sorry to be so dumb - all help will be greatly appreciated!

    John
     
  12. Nodsu

    Nodsu Newcomer, in training Posts: 9,431

    A decent PSU will shut itself off when it detects a short on one of its outputs, so frying it with a faulty mobo is unlikely.

    500W vs 550W is a mere 10% difference.. I don't think it would matter much.

    Again, are you sure it is the motherboard that is dead? A fried PCI card or a RAM stick can just as well prevent the system from powering up. (Or did you already try with a bare mobo)?
  13. whitefort

    whitefort Newcomer, in training Topic Starter

    This is partly what's bugging me. When I turn the PC on, I get power for a spilt-second, then it all shuts off. Doesn't that look like the PSU might be doing exactly what you suggest - finding a fault and shorting out?

    I've already taken out the PSU and packaged it for a warranty return, but I'm wondering if they'll get it, test it, and find it's fine.

    In the meantime, I'm wondering if I *should* just bite the bullet and buy a different PSU - maybe a 600W. If THAT doesn't work, then at least I've ruled out a faulty PSU as the problem. Alternatively, I'll just have to wait a month or two until the current PSU is replaced under warranty.

    Today, in the shop, the guy DID get the motherboard running. He didn't connect the PC to a monitor, because the PSU he used didn't have a socket for my graphic card connector, but the PC fans were spinning and the leds on the fans lit up. He was pretty adamant that this ruled out motherboard damage. And since all the drives, memory, cards etc were still inserted in the motherboard, presumably this means they aren't guilty of causing a short?

    I think I really just need to buy yet another PSU and see what happens...

    BTW, when I bought my ANTEC, the on-site reviews were all good. Since then, there are at least three where people complain that theirs burned out exactly like mine.


    Maybe Antec isn't such a good make after all?
  14. N3051M

    N3051M Newcomer, in training Posts: 2,800

    the power of the PSU you should get depends on two things:
    -your current setup needs
    -what you plan to do with your setup eg upgrades, rebuilds, overclock etc

    You would normaly use a PSU calculator like this http://www.extreme.outervision.com/psucalculator.jsp

    to find your absolute minimum, then add about 50W for headroom, and that will give you what your PC needs. Then if you think that you will add more HDDs later and overclock etc you will need to take that into consideration, then get a PSU probably a bit more beefy than the recommended one.
    Don't forget that there are some devices that eat power a lot more than others (eg: graphics card etc)
    Then you start shopping for your PSU.. looking at reviews, the amps and ratings etc..

    Antec is a pretty reliable brand.. i think it may have been just a bad batch or something...
  15. whitefort

    whitefort Newcomer, in training Topic Starter

    Thanks, guys.

    I did the PSU calculator, and got a rating of 430 - So I guess my 500 should have been OK.

    But I do hope to do more upgrading in the future (if I ever, ever get this PC to work again!), so I'm considering buying a 600W supply. If the PC still won't start up, then I'll have at least ruled out the PSU as the cause of the trouble.

    I thought Antec would be a good buy, and to be fair, the user reviews on the website were good. However looking at them today, I see that at least 4 people have had the same experience as myself in the past month - worked fine for a while, then a catastrophic burnout. Maybe a bad batch got out of the factory or something.
  16. whitefort

    whitefort Newcomer, in training Topic Starter

    Hi, guys - I really appreciate your help so far, and while I've solved one problem, I've hit another - any help would be very appreciated.

    I got a new power supply (jeantech 600w), and at first everything seemed fine - I turn it on, the CPU, case, and graphic cards turn and the case leds come on. I get a single beep and the POST starts to run on the screen. It correctly reports the memory. So far so good.

    Then the whole thing totallly shuts down. No fan, no lights, just totally turned off. Sometimes this happens during post, sometimes it gets as far as trying to start windows. This makes me think it has something to do with how long the PC's been running, rather than what the PC's actually doing (software-wise) at the time.

    But I don't know. I feel I've made some progress, but have hit a brick walll again.

    Help!!?

    John
  17. nickslick74

    nickslick74 Newcomer, in training Posts: 883

    You might want to check and see if the heatsink is making good contact with the processor. It sould be that your processor is overheating. You could also try and get in to the BIOS at boot up and check your temps. If they are climbing, then that is your problem.
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