?PSU problem

Discussion in 'Hardware' started by Bigsistermidnight, Feb 20, 2006.

  1. Bigsistermidnight

    Bigsistermidnight Bit Poster

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    The word has got out that I am doing my A+ and I have been asked if I will have a look at a friends pc. Was working with no problems, then next time they tried turning it on nothing happened. They tried other electrical items in the wall socket (obvious I know), but that was ok. I have been reading up on here and my books and I think the PSU is the problem. I am planning to look at it tomorrow and just looking for some advice really. This is my first time trying to troubleshoot hardware, I have a multimeter (used one before) and a lot of courage! :biggrin

    Any advice and suggestions gladly welcome. :oops:
     
    Certifications: SG Computing Studies(ha ha),ECDL
    WIP: A+
  2. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    Because the PSU and the motherboard are closely coupled it is by no means sure that a PSU is the problem here.

    I'd suggest that it is a good time to buy a PSU tester (Maplins sell them among other places). This allows you to test a PSU without involving a motherboard to switch it on. You can then check all the voltages are correct.

    Do you get a beep on power on?

    Try removing all the cables for drives from the motherboard (noting where and how they plugged) and any extra cards other than the video one. Try again. Any change?

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  3. Bigsistermidnight

    Bigsistermidnight Bit Poster

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    Thanks Harry

    Theres no noise at all. Will try removing all cables and see if that helps.
     
    Certifications: SG Computing Studies(ha ha),ECDL
    WIP: A+
  4. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    No noise usualy means the processor isn't starting. Unfortunately this can be caused by almost anything.

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  5. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    You are doing the A+ because you want to be a PC tech person -yes. Well PSUs are cheap, I would personally just go and buy one and if it isn't the PSU on this occasion, well then you have one in stock so to speak. You will use it sooner or later, trust me :D
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)
  6. noelg24

    noelg24 Terabyte Poster

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    I agree with Bluerinse...if u feel it is the PSU go out and buy a new one...I bought a new 550W for only £32!! 8yrs ago I bought a 350W for about £50+!!! times have changed...but again like Bluey says if it aint the PSU u got one spare and u never know when it will come in handy....*need to get rid of blown up PSU very soon* ahem!!
     
    Certifications: A+
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  7. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    Surely, the easiset (and first?) check would be to plug the PSU in with nothing connected and see if the fan spins up? Or am I missing something obvious?
     
    Certifications: A+, Network+
    WIP: 70-270
  8. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    Most PSUs that I have seen recently won't do anything when switched on when not connected to anything.

    They need the motherboard to tell them to switch on.

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  9. snoopy51

    snoopy51 Bit Poster

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    At home, I take out my multi-meter and identify each pin and the layout.

    At the field, I simply plug a PSU tester in and let the LED tell me what is wrong.

    It is an excellent idea to stock a PSU. Since this is an old machine, be careful of what PSU you buy!

    For most PC, we have AT(old, but very few left), ATX v1.x and ATX v2.x, and now BTX.

    PSU and motheboard are fully integrated with each other, unless you have a motherboard or a tester, you will not able to do too much. Well, you can manually jump two pins to start the PSU!

    Good luck!
     
    Certifications: MCSE (2K, 2K3), MCDBA, IBM CP, LPIC-1
    WIP: LPIC-2
  10. Bigsistermidnight

    Bigsistermidnight Bit Poster

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    I have just got back from looking at the PC and my friend has decided to donate it to me for to help my studying! :eek: However we used the multimeter and got nothing! I did note that the PSU was AT. So I have gained a PC I am not scared to take apart and put back together again.

    A BIG thank you to everyone for the advice and suggestions. I only started self studying my A+ a couple of weeks ago - so this was quite a daunting task. :D
     
    Certifications: SG Computing Studies(ha ha),ECDL
    WIP: A+
  11. Boycie
    Honorary Member

    Boycie Senior Beer Tester

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    Oh, so you have a computer to play with :)

    AT power supplies will have 2 power connectors to the mobo, P8 and P9. Make sure the 2 black wires go back to back......
     
    Certifications: MCSA 2003, MCDST, A+, N+, CTT+, MCT
  12. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    If this is an AT PSU then the main switch will be in the mains lead direct from the PSU, rather than a lightweight cable to the motherboard.

    In this case the PSU should power on without being connected to the motherboard.

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  13. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    Bear in mind that some PSUs in certain branded models of computers like HP or Dell etc are not standard ATX. I am dealing with a Dell right now that does not have a standard type PSU. Drives me nutso, that you have to buy from Dell or faff around trying to find an expensive equivalent :x
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)

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