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PSU Blown. Help!

I accidentally switched the voltage switch at the back (dont ask why i dunno myself) and the PSU blew with a little bit of smoke coming out. Thankfully the PC was off at the time and later i unplugged the entire unit and opened the side pannel to see whether there was any visible damage. None i could see or smell the components (mobo, graphic card, harddrive) everything seemed normal. Im worried sick that was there any component damage? Are there failsafes inbuilt in the PSU to prevent any further damage to components.
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  1. Best answer
    Since the PSU was off, it is unlikely any power went on the 12/5/3.3V rails that power most componenets. The only thing that uses 5VSB (the only rail that has power while everything else is off) is the motherboard and possibly some USB devices.

    If you are in a 230-240V country, enabling the doubler circuitry would cause the primary-side semiconductors to exceed their breakdown voltage, short out and blow the fuse, in which case little to no power would get transfered to the 5VSB rail before failure.

    If you are in a 115-120V country, disabling the doubler might have caused the 5VSB's transformer primary to go into saturation and destroy the primary-side switching semiconductors, in which case little to no power should have been transferred to the 5VSB rail.

    So in either case, the probability of damage to anything outside the PSU is low.
  2. rafaeshahid_39 said:
    I accidentally switched the voltage switch at the back (dont ask why i dunno myself) and the PSU blew with a little bit of smoke coming out. Thankfully the PC was off at the time and later i unplugged the entire unit and opened the side pannel to see whether there was any visible damage. None i could see or smell the components (mobo, graphic card, harddrive) everything seemed normal. Im worried sick that was there any component damage? Are there failsafes inbuilt in the PSU to prevent any further damage to components.

    is your country power 220v and not 110v?? here in the us most of the older ps that have that switch if your on 110v and switch to 220v nothing happens..but if if the other way around most times there a fuse that suposed to pop if it dont most time the caps in the power supply pop. power supplys (good ones do have an over volt protection) the ps dies not the mb. hopfully your mb is fine. (a lot of new mb keep low voltage line on) (power good led) standby power.
  3. InvalidError said:
    Since the PSU was off, it is unlikely any power went on the 12/5/3.3V rails that power most componenets. The only thing that uses 5VSB (the only rail that has power while everything else is off) is the motherboard and possibly some USB devices.

    If you are in a 230-240V country, enabling the doubler circuitry would cause the primary-side semiconductors to exceed their breakdown voltage, short out and blow the fuse, in which case little to no power would get transfered to the 5VSB rail before failure.

    If you are in a 115-120V country, disabling the doubler might have caused the 5VSB's transformer primary to go into saturation and destroy the primary-side switching semiconductors, in which case little to no power should have been transferred to the 5VSB rail.

    So in either case, the probability of damage to anything outside the PSU is low.


    Thankyou that is helpful. I will take my computer to professionals today and get the PSU changed to check whether the components are running fine. Secondly as this blow up occured it took out my UPS's normal charging mode on which it runs when electricity is in constant adequate supply. It does turn on in the standby mode but in charging mode. People i asked have said it is probably a fuse blow which could be replaced. What would you say?
  4. smorizio said:
    is your country power 220v and not 110v?? here in the us most of the older ps that have that switch if your on 110v and switch to 220v nothing happens..but if if the other way around most times there a fuse that suposed to pop if it dont most time the caps in the power supply pop. power supplys (good ones do have an over volt protection) the ps dies not the mb. hopfully your mb is fine. (a lot of new mb keep low voltage line on) (power good led) standby power.


    Here its 230v i think and i accidentally switched it to 115v while the system was plugged (causing the blowup) but not turned on as i shut it down a bit before this happened. This is my rig:

    Intel i3 3.2 ghz
    Intel Motherboard DH55HC
    Corsair 2gb DDR3 1333mhz Value select (x2)
    XFX HD4870 DDR5 1gb
  5. smorizio said:
    (a lot of new mb keep low voltage line on) (power good led) standby power.

    Actually, ALL motherboards "leave" 5VSB on since they are hard-wired to the PSU's 5VSB which is powered whenever the PSU is receiving mains power, there is no way to turn it off other than disconnecting the PSU or putting the hard-switch in the Off position.

    The main reason 5VSB exists in the ATX standard is providing power for suspend-to-RAM functionality which nearly all ATX boards ever made since the ATX standard was introduced support. Many boards/CPUs even prior to ATX already supported STR sleep mode but simply lacked any means of shutting down unnecessary PSU rails.
  6. rafaeshahid_39 said:
    Secondly as this blow up occured it took out my UPS's normal charging mode (...) People i asked have said it is probably a fuse blow which could be replaced. What would you say?

    I'd say check your UPS' troubleshooting check list and if the manufacturer has monitoring software, install that and see what the software has to say about it. There may be an option to initiate a self-test in there and with some luck, this might tell you what appears to be wrong.

    If you blew the battery fuse, the UPS should be reporting a battery error.
  7. Just checked the UPS the fuse is blown so i guess that just needs replacement. So ultimately i just need to replace or repair the power supply (my computer guy says it can be easily repaired) My PSU's a Cooler Master Xtreme Power 600 watts. Read it has quite a few failsafe measures so i guess i dodged a bullet there.
  8. InvalidError said:
    I'd say check your UPS' troubleshooting check list and if the manufacturer has monitoring software, install that and see what the software has to say about it. There may be an option to initiate a self-test in there and with some luck, this might tell you what appears to be wrong.

    If you blew the battery fuse, the UPS should be reporting a battery error.



    Just checked the UPS the fuse is blown so i guess that just needs replacement. So ultimately i just need to replace or repair the power supply (my computer guy says it can be easily repaired) My PSU's a Cooler Master Xtreme Power 600 watts. Read it has quite a few failsafe measures so i guess i dodged a bullet there.
  9. Not a great PSU; it really shouldn't be labeled as anything more than a 450W PSU: http://www.hardwaresecrets.com/article/Cooler-Master-eXtreme-Power-Plus-600-W-Power-Supply-Review/1034/9 Even if it can be repaired I would replace it with a good quality PSU.
  10. Rugger said:
    Even if it can be repaired I would replace it with a good quality PSU.

    Even if it could be repaired, buying a good PSU would likely be cheaper...
    - $25 just to open the PSU for a repair assessment
    - $25-50/h for the repair itself
    - $5-15 in parts

    So you'd end up paying $60-120 to repair a $50 PSU assuming only the primary-side switches blew up. If a bunch of related components like snubber circuits and gate drive circuits blew up too (which is very likely the case) then the PSU is beyond repair for all practical purposes.
  11. InvalidError said:
    Even if it could be repaired, buying a good PSU would likely be cheaper...
    - $25 just to open the PSU for a repair assessment
    - $25-50/h for the repair itself
    - $5-15 in parts

    So you'd end up paying $60-120 to repair a $50 PSU assuming only the primary-side switches blew up. If a bunch of related components like snubber circuits and gate drive circuits blew up too (which is very likely the case) then the PSU is beyond repair for all practical purposes.


    Haha thanks for the heads up my friend but the case in this part of the world is quite different.. Getting it repaired by Cooler Master for around 20$ total. But i do realize that getting it repaired in the states is actually more expensive than buying a new one.
  12. Hope the repair goes well...I'd still seriously consider getting a better PSU.
  13. Rugger said:
    Hope the repair goes well...I'd still seriously consider getting a better PSU.


    Will keep that under consideration. Wouldn't haveto pay jack if I dont feel the repairs upto scratch anyway. I'll find out its status tomorrow and will keep the thread posted.
  14. Solved! I got my PSU repaired for around $10 from Cooler Master and voila all is good, updated my BIOS and removed the 32-bit Windows 7 Ultimate for the 64-bit version and its running smoothly. Thankyou for your responses they were really helpful.
  15. Best answer selected by rafaeshahid_39.
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