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For all of us undertaking A+, lets do some work together...

Discussion in 'A+' started by albertc30, Nov 15, 2008.

  1. albertc30

    albertc30 Kilobyte Poster

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    :rolleyes:Hello everybody.
    This is simple and pretty much straight forward.
    For everybody out there going for the A+ here is a situation so lets put our good skills to practise and let’s try to sort this problem.

    I have got a friends computer to fix.

    Sometimes it turns on by pressing the power button sometimes it doesn't.
    When it does apparently there's nothing going to the screen.

    At first glance I'd put my money on either the motherboard being busted or the power supply faulty.

    What are your comments on this particular situation?

    Cheers,
    Albert, C
    :rolleyes:
     
    Certifications: CCNA
    WIP: 220-701 - A+
  2. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    Oh, is it.. then why are you asking others for their comments?
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)
  3. Mr.Cheeks

    Mr.Cheeks 1st ever Gold Member! Gold Member

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    Fixed! 8)
     
  4. BosonMichael
    Highly Decorated Member Award

    BosonMichael Yottabyte Poster

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    Have you rebooted? :twisted:

    Sorry, couldn't resist. :p
     
    Certifications: CISSP, MCSE+I, MCSE: Security, MCSE: Messaging, MCDST, MCDBA, MCTS, OCP, CCNP, CCDP, CCNA Security, CCNA Voice, CNE, SCSA, Security+, Linux+, Server+, Network+, A+
    WIP: Just about everything!
  5. albertc30

    albertc30 Kilobyte Poster

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    well you all, wanna take the miky out me? well then bring it on...
    For those who want to learn bring up your answers.
     
    Certifications: CCNA
    WIP: 220-701 - A+
  6. albertc30

    albertc30 Kilobyte Poster

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    yes michael i have and it won't reboot by pressing the reboot button lol
    Turn the power off and then it won't even power it.

    My first steep will be tsting the power supply with a multimeter and see hows the current on it. Follow Mike Meyers steeps in the book.

    Some of us take this seriouslly some are just after a good laugh. I don't mean you by the way even though your comment was funny in a really bad way... lol

    It would be even simpler if I just change the PS + motherboard + cpu + mem and it would all be over with but what would I learn rather then just being laisy at finding the fault?
     
    Certifications: CCNA
    WIP: 220-701 - A+
  7. greenbrucelee
    Highly Decorated Member Award

    greenbrucelee Zettabyte Poster

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    Test the power supply with a multimeter, if it isn't bringing up the correct readings then that'll be the culprit.
     
    Certifications: A+, N+, MCDST, Security+, 70-270
    WIP: 70-620 or 70-680?
  8. Markyboyt

    Markyboyt Kilobyte Poster

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    Your going to test the current with your multimeter?
    For that you would either need your meter in series in the circuit and be confident that the current was lower than the fuse in your meter, or a clamp to put over the wire you wish to test, also the circuit would need to be live and functional for current to be flowing, if something else was causing it not to power up then it might be that the circuit hasn't yet been completed.

    Personally I would check the voltage coming into the PSU, if that was good then I would check the voltage on the supplies out of the PSU starting with the motherboard.

    Oh and another tip, if you want to check anything with a multimeter with some degree of accuracy, ensure you buy a good one, some £20 maplin job will lead you on a wild goose chase, causing more hassle than its worth.
     
    WIP: A+
  9. JonGlory

    JonGlory Byte Poster

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    Take the front bezel off machine and try the power button, also try a different monitor. May save you a lot of hassel.
     
    WIP: LIFE
  10. dmarsh

    dmarsh Terabyte Poster

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    Analogue multimeters can have a very simple low impedance design, be very cheap and perfectly adequate for such purposes.

    Testing the PSU sounds sensible, just as effective if you are working in a repair shop could be just switching it out for a similar PSU.

    Could just be the switch but modern microswitches are normally good for years of abuse.

    Yep, definitely try a different monitor just to eliminate that.

    You are correct that poor quality motherboards and PSUs are the most common cause of such issues.
     
    Certifications: CITP, BSc, HND, SCJP, SCJD, SCWCD, SCBCD, SCEA, N+, Sec+, Proj+, Server+, Linux+, MCTS, MCPD, MCSA, MCITP, CCDH
  11. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    I'd say it depends on the age and model of motherboard. The symptoms are typical of a PSU failure, and also typical of capacitor failure on the motherboard.

    The PSU should be tested with a PSU tester plus multimeter - this is more reliable than just the multimeter alone, as the way the motherboard interacts with the PSU can confuse things.

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  12. tripwire45
    Honorary Member

    tripwire45 Zettabyte Poster

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    That would be my first suggestion as well...try the simple stuff first. What if the connection to the power button is bad?
     
    Certifications: A+ and Network+
  13. del_port

    del_port Byte Poster

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    I think why people are joking around is you have said this is simple and straightforward,this isn't a simple or straightforward repair.

    A simple and straightforward repair is when there is only one possible way of fixing it with no element of doubt anywhere.

    Here is an example of a straighforward job,pc no longer powers on when power button is pressed at the front of the pc,this is a 5 minute job and easy to fix,buy new power supply and check front button connection.

    What if it is neither the power supply or the motherboard,what are your next options if both of those are fine?

    The A+ doesn't really focus on multimeter use,it does mention a multimeter and the basics of what it does.

    After the motherboard and power supply i'd then link the graphics card into the equation,is it a stand alone card or onboard graphics?

    Here is what it isn't:
    damaged dead processor [it wouldn't show any sign of life it was]
    bios instant shut off to save the processor from overheating

    And the first step in the A+ is to get a load of information from the customer about the lead up to this fault before you even begin,you have told us practically nothing at all that the customer said.

    This fault finding using the customer is focussed on very heavily in the A+ .It comes up every few chapters,ask the customer this,ask them that,and so on.It's part of the 6 step process mentioned time after time in the A+.

    I would also be taking the front panel off the pc and checking the actual power button and see how reliable it is when pressed,i agree with the others who suggested this.

    This still doesn't explain the lack of graphics though.
     
    Certifications: A+ and MCDST 70-271
    WIP: mcdst 272
  14. albertc30

    albertc30 Kilobyte Poster

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    Hello del_port.
    When I have said this to be straight forward I meant the fault, not the actual repair side of things or to diagnostic the fault, maybe my bad choice of words yet again, it seems to happen allot, for that I apologise.

    I have already tested another power supply, a thermaltake toughpower 750W and the problem still lies ahead of us. The pc sometimes powers up and sometimes it doesn't power at all, sometimes it resets when pressing the reset button sometimes it just stops working, example the cpu fan stops spinning and no lights in the front of the pc.
    So as to this, I would say it's not the power supply then. I must say as well that whenever the pc gets started and nothing goes to the screen, but clearly there is power flowing through it I hear no post bip at all, there is no beeping.
    You have said that a dead CPU would show no signs of life so I take it the motherboard wouldn't even start, right?
    So if that's the case then I'm compelled to believe that the motherboard is at fault.

    From my friend's history, the pc was running fine, switch it off and then the next time he went to turn it on the power was there but no beeps as peer usual and turning it of sometimes would cause it no to go back on again.

    Thanks everybody for all your comments and very appreciated all the important info provided by all of you and once more, I am sorry for my poor choice of words.

    Carry on the good work.
    Albert, C
     
    Certifications: CCNA
    WIP: 220-701 - A+
  15. albertc30

    albertc30 Kilobyte Poster

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    Thanks greenbrucelee for your comment, much appreciated.
     
    Certifications: CCNA
    WIP: 220-701 - A+
  16. albertc30

    albertc30 Kilobyte Poster

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    Cheers Markyboyt.
    I haven't tested the power comming from the wall socket as it also feeds my other two systems with no problems at all so I take it when it comes to the propper current coming from there we have got no problems.
    As to the multimeter yes, I have got my thoughts on a good fluke multimeter as the guys in the engineering department say they are the best.
    thanks for your comment.
    Albert, C
     
    Certifications: CCNA
    WIP: 220-701 - A+
  17. del_port

    del_port Byte Poster

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    "You have said that a dead CPU would show no signs of life so I take it the motherboard wouldn't even start, right?"

    With a dead cpu the machine will power up as normal,but nothing will happen,you'll get nothing on the display screen,the processor fan and case fans will spin normally.

    With a power surge you also get the same result as a dead processor,nothing on screen.
    A power surge may knock out every bit of pc hardware you own,all at one time,it can take a dozen hardware items in one go and render them useless.

    As you can see i have had these problems in the past and i can remember certain faults i've come across.

    With graphics cards issues you can also get nothing on screen.

    I misread your first post saying
    "When it does apparently there's nothing going to the screen"

    So is this nothing ever,he never gets a display at any time?,i read it as sometimes gets a picture display?

    Here is another thing i try myself when i am faced with a pc which doesn't come back on normally.

    I reset the bios settings,you'll need the motherboard manual to work out which pin clears the cmos settings ,jp8 is a common one,manuals can be found online.

    There is a bios setting which refers to pc behaviour after unexpected shut downs,,or after power failure it states what the pc should do,should the pc remain powered off,should it return to the previous working state and power on as normal etc..
     
    Certifications: A+ and MCDST 70-271
    WIP: mcdst 272
  18. supernova

    supernova Gigabyte Poster

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    yeah testing current isnt easy as its load based and is component specific.

    As stated Voltage is normally sufficient in fault finding and is easy as it should remain constant.

    Of course you still need to look at current, make sure your not overloading your PSU.

    However, saying that the first step in hardware fault finding would be a visual inspection capacitors, connections etc

    But yes it does sound like the PSU would be the best culprit to test.

    That is common with failing PSU's
     
    Certifications: Loads
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  19. Markyboyt

    Markyboyt Kilobyte Poster

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    I can agree with them, you don't even need an all singing dancing one really. I have a fluke 112 meter and its never let me down, whereas guys at work have gone down the wrong path for ages before deciding to borrow a better meter. My fluke cost me £145
    That said at work we use them current wise for monitoring battery drains on vehicles which as a general rule is anything over 0.05A is too high, a meter thats even 0.1A out is worse than no meter.
     
    WIP: A+
  20. del_port

    del_port Byte Poster

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    quote
    "I have already tested another power supply, a thermaltake toughpower 750W and the problem still lies ahead of us. The pc sometimes powers up and sometimes it doesn't power at all, sometimes it resets when pressing the reset button sometimes it just stops working, example the cpu fan stops spinning and no lights in the front of the pc"

    They weren't getting anywhere with a new power supply either though,they tested with a thermaltake toughpower 750W .
     
    Certifications: A+ and MCDST 70-271
    WIP: mcdst 272

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