PSU went up in smoke. New PSU won't boot PC

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  1. Posts : 4,751
    Windows 7 Home Premium 32-Bit - Build 7600 SP1
       #31

    One thing to be aware of is the motherboard might be bad, but other things might have been affected also. Not trying to be the bearer of bad news, but the motherboard might not be the only that that was fried.
      My Computer


  2. Posts : 104
    XP
       #32

    bigmck said:
    One thing to be aware of is the motherboard might be bad, but other things might have been affected also. Not trying to be the bearer of bad news, but the motherboard might not be the only that that was fried.
    He is spot on. Never assume good or bad is defined by something working or not working. Reality is more complex. Learning how to fix things technical also teaches realities of everything else in life.

    A good power supply can act defective in an otherwise perfectly good computer. A defective supply can still boot and run a computer. Other items may have been affected. That concept is called overstress.

    Can anyone honestly answer your questions? No. Hard facts are not provided. Without numbers, then every answer can only be wild speculation.

    A first post said get a meter and request some instructions. Make sure all parts remain connected and unchanged. Then use that meter and instructions to obtain some three digit numbers. Then a next reply exonerates or accuses each specific part - without wild speculation. Without phrases such as 'maybe' oir 'did you try'. An engineer who designed this stuff cannot provide assistance. Your replies are only as useful as information that you provide. No numbers means speculation. "It might be ...".

    BTW, removing RAM was completely unrelated to your computer's symptoms. As made obvious had the shop used a meter.

    A power 'system' has many components including a power controller. That controller decides when a PSU can power off, power on, and even when the CPU is permitted to operate. Is that power controller defective? Or does it get some input that says, "Do not start?". Or does it get some input that does not ask it to start? All these questions are layman simple. Had meter numbers been provided, then every question would have been answered by conclusions from hard facts. And you would have learned what a computer really does.

    At this point, keep buying new parts until something works. You are doing what one would do without asking for help. Shotgun. You do not even know if a motherboard is defective. And never learned why failure happened - how to avert future failure. See that second paragraph. A good motherboard can act defective in an otherwise good computer. Shotgunning can fix a defect or only cure symptoms. Best (as in everything in life) is to see a defect before fixing it. Before disconnecting anything. That means perspective (ie numbers).

    A final point. Always learn from mistakes. Mistakes are the source of most knowledge.
      My Computer


  3. Posts : 194
    Win 7 Professional 64 bit
    Thread Starter
       #33

    Thanks for your suggestions. I brought the motherboard back from the local shop where they again did a round of tests with and without my RAM and the results were the same. They even tried with a different stick and there was no display. They tried my GPU, on board graphics, nothing worked. So it finally zeroes down to the motherboard or the CPU. I will try out with a new board and see what happens. Will keep you guys posted.

    Keeping fingers crossed.
      My Computer


  4. Posts : 104
    XP
       #34

    probuddha said:
    Thanks for your suggestions. I brought the motherboard back from the local shop where they again did a round of tests with and without my RAM and the results were the same. They even tried with a different stick and there was no display.
    So they did not observe what was relevant. They did not use a meter for 30 seconds to learn what exists. Then kept removing or swapping parts (ie RAM) that are totally unrelated to the power 'system'. Absolutely no reason to cross fingers. If they did not use a meter, then they have no idea how electricity works.

    Everything remains suspect. Nothing has been exonerated.

    Why would a CPU not execute? A CPU cannot do anything until the power controller lets it work. What is necessary to see what a power controller is doing? A meter. No way around that hard reality. Is the CPU defective, or a special power supply that power the CPU defective, or power controller defective, or power controller sees something else that is defective? Everything remains on a list of suspects. Nothing has exonerated a PSU.

    Reminds me of a scene from Casablanca. "Major Strasser has been shot... round up the usual suspects."
      My Computer


  5. Posts : 4,751
    Windows 7 Home Premium 32-Bit - Build 7600 SP1
       #35

    westom said:
    probuddha said:
    Thanks for your suggestions. I brought the motherboard back from the local shop where they again did a round of tests with and without my RAM and the results were the same. They even tried with a different stick and there was no display.
    So they did not observe what was relevant. They did not use a meter for 30 seconds to learn what exists. Then kept removing or swapping parts (ie RAM) that are totally unrelated to the power 'system'. Absolutely no reason to cross fingers. If they did not use a meter, then they have no idea how electricity works.

    Everything remains suspect. Nothing has been exonerated.

    Why would a CPU not execute? A CPU cannot do anything until the power controller lets it work. What is necessary to see what a power controller is doing? A meter. No way around that hard reality. Is the CPU defective, or a special power supply that power the CPU defective, or power controller defective, or power controller sees something else that is defective? Everything remains on a list of suspects. Nothing has exonerated a PSU.

    Reminds me of a scene from Casablanca. "Major Strasser has been shot... round up the usual suspects."
    He has a new PSU. We have moved past that for the moment.
      My Computer


  6. Posts : 1,850
    Windows 7 pro
       #36

    bigmck said:
    He has a new PSU. We have moved past that for the moment.
    Does that mean that it is any good? Manufacturers have been known to release bad parts or it might have already been damaged somehow. IMO simply stating that something is new isn't enough. I agree with westom in that until it is tested by a meter all we can do is speculate.
      My Computer


  7. Posts : 194
    Win 7 Professional 64 bit
    Thread Starter
       #37

    Agreed that the new PSU could be a dud but when the system was checked with another PSU, it gave the same results
    So we can rule out the PSU to be the culprit here
      My Computer


  8. Posts : 4,751
    Windows 7 Home Premium 32-Bit - Build 7600 SP1
       #38

    probuddha said:
    Agreed that the new PSU could be a dud but when the system was checked with another PSU, it gave the same results
    So we can rule out the PSU to be the culprit here
    I doubt if it is bad, but to find out, hook the PSU to your DVD drive. press the button on the drive and see if it opens.
      My Computer


  9. Posts : 3,487
    Win 7 Pro x64/Win 10 Pro x64 dual boot
       #39

    A meter can fool you too. It's not always a clear cut case.

    1. You can test an unloaded PSU and determine that the voltages are all there, but one or more disappears or falls greatly under load either due to a fault in the PSU, or a short on the motherboard or somewhere else in the system.

    2. A component on the motherboard or other item could be burned "open" and not shorted. A shorted component will cause the voltage to drop to zero or nearly zero, whereas an open component will cause the voltage output from the PSU to read normally (assuming it read normally unloaded).

    What we know so far:

    - The graphics card and RAM are not the source of the problem. They have been swapped out and there has been no change to the operation of the computer.

    - The computer will not boot using a presumably working supply in the computer shop, nor will it work with a brand new supply. I'm not saying that the brand new supply is not defective, but it is unlikely that both it and the repair shop's PSU is defective at the same time.


    What we don't know:

    - Does the computer at least beep when started up?

    - Are there any burned smells either from the motherboard or from the old power supply?

    - Are there any burned or scorched marks on the motherboard itself? Do the regulator components around the CPU look burned or bubbled?

    - Are the capacitors on the motherboard swollen or puffy? Or ruptured?

    These are all things that I would ask in the absence of a meter, since the OP may not have one, or may not have access to/know how to use one. I would not depend on the repair shop to do a competent job of investigating the problem.

    Judging by the symptoms described by the OP, I would tend to suspect the motherboard. Given that the voltage regulation circuitry is the first thing encountered when the PSU comes into the board, a failure in the PSU could have caused the voltage regulation circuitry on the motherboard to fail for either of the 5V and 3.3V lines, or both. Either one will prevent the motherboard from booting. An extreme failure will compromise components by burning them.

    One of the first things you do before working on a damaged circuit with a meter is to unhook the power and use your eyes and nose. Look and smell for burning. Then hook up the power. Shorted or compromised components can pop or burn, causing further damage or injury.

    And probuddha, your Radeon card will work with any motherboard you select, as long as it hasn't been damaged.
      My Computer


  10. Posts : 194
    Win 7 Professional 64 bit
    Thread Starter
       #40

    Thank you so much Mellon Head for your advise.

    Let me answer the questions you have asked above:


    - Does the computer at least beep when started up?

    No, not anymore


    - Are there any burned smells either from the motherboard or from the old power supply?

    The guy at the computer repair shop told me that he got some burnt smell on the motherboard. As for the PSU, let alone the smell, I could already see the charred and puffed capacitors inside.


    Are there any burned or scorched marks on the motherboard itself? Do the regulator components around the CPU look burned or bubbled?

    Not that I have noticed myself.

    I will be going to a computer shop today and get a new motherboard and hopefully it will put things in order.

    Also, one vital question to ask you guys

    How can I prevent this from happening again? My pc wasn't hooked on to an UPS but I was using a surge protection strip (which clearly didn't do its job well)

    Should I get a UPS or a voltage stabilizer?

    Kindly advise

    Thanks again
      My Computer


 
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