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Two power supplies in two days! (3rd in a year). HELP!!!!

By Mugsy ยท 36 replies
Jun 3, 2006
  1. HELP! (I'm having to type this on my 300MHz notebook).

    Yesterday, my second power supply in 12 months bit the dust. I spent all afternoon today cleaning any dust out of my PC (it wasn't too terrible, but I thought that might be the cause) and replacing the PSU. The computer fired up, but I immediately started smelling that same odd (like burning plastic) smell. Less than a minute later, the psu died... litterally in a puff of smoke. It was also very hot to the touch immedately after.

    Now the technical details:

    A year ago, my 400watt psu blew. Suspecting I was putting too much of a drain on it (Athlon XP 3200+ cpu, 4 IDE devices, but no lights or fancy stuff), I replaced it with a new 550watt psu.

    Flash forward 54 weeks later to yesterday, I suddenly smelled that burning smell, followed soon after by the PC's power failure.

    Today I found a replacement 550watt psu... used but in great condition. As noted above, it ran for about one minute before dying in a puff of gray smoke.

    I have no clue what is going on here. Anyone? HELP!
  2. iss

    iss TechSpot Chancellor Posts: 1,994

    There are two things I can think of right off the bat.

    1. faulty house wiring where you are pluging the PSU in at. (unlikely but possible)

    2. when your PSU went up in smoke the other day it took the mobo with it. and since the mobo has been damaged it is going to toast any PSU you hook up to it.
  3. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    I always forget certain details.

    I always forget to include cerain details:

    After the first blow-up a year ago, I purchased a 750watt backup power supply (a UPS) with line conditioning, so "bad power" is an unlikely cause here.

    And as mentioned above, I was up and running for a full minute, even entering BIOS, before the new psu blew tonight, so the MB and CPU were (and hopefully still are) okay.

    This does seem to be an electrical problem of some sort, but damned if I know what.

    Thanks for any feedback you can give.
  4. iss

    iss TechSpot Chancellor Posts: 1,994

    I would suggest that if yu get a new PSU that you strip the computer down to just the CPU and then power up if the PSU doesnt tank then start adding components one at a time until everything is installed. yuo might also want to double check the mobo and make sure no metal is contacting it in the case and causing a short.
  5. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    The MoBo?

    Hi, thanks for the reply.

    I've heard others suggest the MoBo, but I can't figure out what *about* it that might cause this problem.

    The possibility of a "short" is something I hadn't considered, though it would seem unlikely as the case was closed up and ran without incident for 12 months before psu #2 blew. But *something* has definitely changed, hasn't it? :)

    Connecting devices until another psu dies seems like a dangerous (to my MoBo) and expensive means of testing. I really need to know if anyone else has ever heard of or encountered this problem before. Too weird.

  6. iss

    iss TechSpot Chancellor Posts: 1,994

    Personally I would not do the add component thing I would just get a new mobo. I think there is little doubt that your mobo is probably the source of your problem.
  7. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    Replace the MoBo without diagnosis?

    Thanks for the reply.

    What do you base your belief that the MoBo is bad? If that's not it, I will have wasted a bunch of money replacing it for no good reason. And MoBo's are a lot more expensive (good ones anyway) than psu's, so I think I need to know exactly what the cause is here before I start blowing money on parts (I got the computer I have now because a year ago when the first psu blew, I was told it fried my MoBo. So I bought another one only to find out it wasn't the MoBo but the CPU that had been destroyed. So I ended up buying a new cpu as well as a replacement psu, and for good measure, I bought a 750watt UPS as well in case it was a power issue.

    That setup ran great for one year until yesterday. But now, new MoBo, new CPU, new psu, new ups, new case and new monitor all running fine for one year, suddenly, psu's are blowing out on me again. Something very weird is going on here and I don't think it's the hardware. And with the UPS running both my PC and LCD monitor (which is still fine), the problem doesn't seem to be the UPS either. I'm stumped.

    PS: I examined my PC power cable for fraying, wear or missing ground pin, but it is fine.
  8. iss

    iss TechSpot Chancellor Posts: 1,994

    Because the mobo is the most llikely culprit it is the only device that draws enough power itself to outright kill a PSU if it is bad. I have seen bad mobo's kill PSU's and vice versa. I have never seen bad ram or a bad optical drive kill a PSU. virtually any other device going bad will normally just cause the computer not to boot, not destroy the PSU.

    Only if you are buying crap PSU's. a decent mobo and a good PSU are pretty close in price.

    YOu should have listened to the first advice you got. the same power surge that killed your CPU also damaged your mobo. The fact it "worked" for almost a year after the incident doesnt change that fact. How exactly would you propose to test your components? you could try plugging them into another computer but IF one of them were the culprit guess what is going to happen to the other system? hint: pppffffttttzzzzzz, but as I allready mentitiond your ram, optical drives etc are unlikely to kill a PSU.
  9. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    Not same MoBo.

    Thanks. I probably described myself badly before. This is not the same MoBo.

    I was incorrectly told by my local dealer a year ago that my MoBo was bad and my cpu was good, but it turned out to be the other way around. The new MoBo I bought was better, so I kept it and just bought a new processor. So both are/were new.

    My MoBo was replaced, the cpu was replaced. As was my ram, vidcard, psu and case (something bigger with more fans). The only thing I reused are my drives (hd's, floppy and dvd-rw). That ran for the next year.

    Now, with almost all new equipment and a 750watt UPS with surge protection providing power to both my pc and lcd monitor, the problem has returned.

    So you can see why I'm so puzzled.
  10. iss

    iss TechSpot Chancellor Posts: 1,994

    hmmm, that is indeed odd.your Battery backup has line conditioning so bad power shouldnt be an issue. of the items you listed that you kept from the old system the one most likely to be a problem is the floppy drive. but usually if the floppy goes bad it just prevents the system from booting.

    it might be worth the trouble to disconnect from the UPS just to make sure it hasnt become a problem.
  11. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    Not grounding?

    I just started a "new" thread as I think I'm zeroing in on the problem. I now believe my computer may not be grounding properly. The psu starts to burn up whenever I start connecting devices to it.

    First, the ONLY thing I connected was the antenna cable from my TV, and immediately the psu began to overheat. Then I connected everything *but* the antenna and it did it again.

    I've found I can connect my video, kb, mouse and Ethernet w/o trouble. When I connected my external USB soundcard, it worked fine too, but I just noticed that when I turned the PC off, the light on the soundcard is still on and I don't remember that being the case before.

    I suspect power is grounding through any metal wire I connect to my PC, but I don't know how to confirm it.
  12. iss

    iss TechSpot Chancellor Posts: 1,994

    if that is the case then there should be some metal contacting the the Mobo that should not be. What I would do to check your idea is remove the mobo from the case, put it on something that wont get static build up and then start adding things like you did with it in the case and see if you get the same result. if you dont then you know it's a problem with the case.
  13. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

    another possibility is faulty house wiring in your outlet....
  14. nork

    nork TS Maniac Posts: 306

    Actually, by the sound of your initial thread post, i would have started my usual rant about how we should all have a UPS. But in your case, you do have a UPS.
    Someone mentioned a short in the case to mobo. Dont forget that screws and small metal objects can get into cases pretty easy sometimes without our knowing it.
    I remember a fella with the same issues as you. I told him to take to mobo out of the case. He wouldnt, swore it couldnt possibly be the issue. In the end he took the mobo out of the case and found a screw almost welded to the mobo or the case, i forget which. He swore there couldnt be a screw out of place but there was!
    I would definitely take the mobo out of the case. You have a short somewhere and my guess it would have something to do with the case.
  15. dmill89

    dmill89 TS Guru Posts: 475

    Actually I believe the problem is your PSU's. Mugsy your system appears to be loaded with power hungry componets. Unless the PSU's you have been buying are good quality (like Enermax,Antec,PC Power&Cooling) they don't put out anytinig near what they are rated at. (I have some 600 watt power supplies that only actually put out about 240 watts). A good 550 watt PSU should have Cost at least $100. I recomend trying a good PSU and getting a higher watage one 600+ watts before you replace your motherboard. Also most good PSU's have a protection feature that won't allow them to turn on and some even sound an audible alarm If your motherboard is shorted,fried ,incompatible,etc so you dont fry the PSU.
  16. nork

    nork TS Maniac Posts: 306

    Very valid points about the protection features of a good PSU and the lies that some cheap power supply mfgrs tell to sell their junk, which, of course, also dont have protection features!
  17. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    More details now. Will check MoBo.

    Since this has occurred with three different psu's, and since checking the MoBo is a lot cheaper that buying a high-end psu, I'm going to take the sucker apart first.

    I noticed yesterday that when I shutdown the PC, the light on my USB soundcard was still on (I don't remember that being the case before), and this morning I plugged a USB gamepad with two leds on it into the PC that I KNOW go out when the computer is shutdown. Plugged into the front USB port, they're off. Plugged into the back, they're on. Hmm.

    My computer is now sitting on my workbench. I've unplugged everything (drives, cables and cards) and still my USB and Ethernet lights go on when I plug into them. Nothing "obviously" wrong inside, so now I'm going to pull the MoBo and see what happens when I power it outside of the case.

    Any suggestions on what to look for (besides the obvious loose screw or burnt wire)?
  18. nork

    nork TS Maniac Posts: 306

    You do want to check the underside of the mobo for burn marks as well as the top of the mobo. Simply look for anything out of the ordinary and especially for burn marks right on the mobo (motherboard). I have seen a few fried power connectors so check that out well, right where the power connector from the power supply connects to the mobo.

    I have also seen some burnt ide cables and burnt pcb boards on hard drives, but, as stated by someone else, these units dont usually cause the power supply to burn up.

    Dont forget to check the cpu as well. If its bad you will clearly see burn marks on it.

    Out of curiousity, what is the make and model of some of these power supplies. Some people have rightly pointed out that if they are generic types that could be your problem. Some cheap units advertise 600 watts when the actual truth is more like 250 watts and no thermal protection as well.
  19. nork

    nork TS Maniac Posts: 306

    Just in case you are inclined to open up your power supply. You need to remember that they can still be charged with serious amounts of power in them, even turned off and broken. If someone knew enough about this, perhaps seeing exactly where the power supply burned up might even help diagnose what caused it. But you should find the answer without looking at the guts of the power supply.
  20. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    Not finding anything.

    Fortunately, there is no need to open this latest psu as it still works.

    My PC is now lying completely disassembled on my table. I removed the MoBo but the only "obvious" annomaly was that I forgot one screw (bottom middle) when I put the MoBo in a year ago. No burn marks or loose screws beneath it. I vacuumed out any dust or debris, of which there wasn't much.

    I put the MoBo on the wooden table, plugged in the psu and plugged in my USB gamepad with the LED's on it. No lights this time, but I can't be sure that is because the short is gone or some other reason.

    I'm going to try a few other things and see what I get.
  21. nork

    nork TS Maniac Posts: 306

    Sometimes screws come loose and you can have intermittent contact. I imagine that could cause problems.
    The main thing is this. There is a layout so that the mobo fits securely to the case and you want your screws to hold the mobo down in a certain pattern for atx motherboards, which is the standard.
    If you look at the holes in the mobo you will see some that have a metal ring around them. These must have metal screws in them. You cant use a plastic standoff. Now you dont have to have a screw in every single hole that is on the mobo, but if there is a metal ring and if you are connecting at that point you have to use a metal screw.
    If you are connecting the mobo at a certain hole and there isnt a metal ring around it, you should use a plastic standoff and not a metal screw.
    I hope you understand this. As i said, you dont have to put a screw in every single hole thats on the mobo, but where you intend to put a screw then you must use metal if there is a metal ring around the hole. If no metal ring then use a plastic standoff.
    And make sure that you have the board tied in well to the case. You dont want to push down on the mobo to install, say, an ide cable only to find that the mobo pushes down to the case. If so, you must install a screw or plastic standoff at that point.
  22. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    Mounting holes

    Good to know about the mounting holes, though the missing screw really didn't concern me.

    My board (ATX) has 8 mounting holes, all with metal rings. It came with brass standoffs that screw into the case and the board sits on those standoffs.

    With the MoBo removed, with just the psu and the case's power switch plugged in, I can turn it on with no LED's lit on my USB gamepad, so maybe the MoBo is okay and doesn't need replacing. I just need to carefully put it back and see if the problem returns.

    Wish me luck.
  23. nork

    nork TS Maniac Posts: 306

    I certainly do wish you good luck, lol.
    But it seems you have likely found the issue i woud imagine.
    That part about the lights not staying on is probably pointing out that all is well.

    Can i suggest you put together just the basics, before you install it into the mobo, the hard drive, one stick of ram, video, keyboard and ram. Get that much working right first then install just these parts into the mobo, make sure all is well again, then add in one item at a time, starting with cdrom, rebooting before you add each extra item back in.
    Are you reformatting your hard drive and installing your os fresh or not?
    Oh, yes, for the hard drive. Some have different jumper when installed alone as opposed to on the same ide cable with another drive like the hard drive.
    So check all jumper configs as well.
    Oh, on the topic of the mobo screws, tighten down firm but dont go overboard as they can strip. Sorry, not to critique your work, just so you know.
    Good luck again.
    We dont know what make and model your present power supply is, do we?
    Not to criticize, just curious is all.
  24. Mugsy

    Mugsy TS Guru Topic Starter Posts: 394   +15

    Problem still there.

    Unfortunately, while it stopped doing it when I removed the MoBo, powered it up and THEN plugged my gamepad in before turning it off, I've just discovered that if I boot with the gpad already plugged in and then shutdown, the LED's on the gamepad are still on. So the problem is still there. Argh!

    The MoBo may be damaged, but it would a costly shame to have to replace what is otherwise a perfectly working board just because I can't plug any grounded devices/cables into it. I need to find a fix.

    This is not a "new" installation and I'm not reformatting anything. There is no need to reformat my drives when I have a perfectly fine working installation. This is not a software issue. It's all hardware.
    The current psu is a generic 480watt supply, but it's not related to my problem as it is the third one I've been through in this nightmare.

    The problem appears to be that raw power goes surging through my psu whenever something grounded is plugged into the back of my PC. Power is leaking out the back somehow, thus lighting the LED's on my USB devices even when shutdown. (Note: the Ethernet port light on the MoBo goes on when I plug an Ethernet cable into it as well. Apparently the whole back (rear ports) of my PC is electrically charged when plugged in.)

    I have no clue how to fix this (or how it happened), but it would seem an electrician might know what to do.
  25. nork

    nork TS Maniac Posts: 306

    I havent anything else to add here, sorry for that. I thought you had solved the problem, i guess you did as well, for a short time anyway.
    I dont think a general electrician could fix this, only a tech with a lot of experience with mobos.
    It seems you either have to get the mobo repaired or replace it. These days, with mobo prices fairly low its likely you can simply replace it cheaper than repairing it.
    One thing i can suggest is that there are a lot of forums around that are devoted to buying\selling pc parts. You might be able to get the same mobo but one that is working and for a fairly low price.
    Have you checked your mobo mfgrs website for possible info on this issue, their faq or their tech support? This may be a known issue with them.
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