TechSpot

Problem When I Plug In 4 pin ATX 12V

By shumon
Sep 9, 2007
  1. Hi everyone first post here.

    anyways Im having this problem. I just built a new computer and am having the exact problem as 99jones99

    Everytime i plug in the 4 pin ATX 12V the comp boots up for 2 seconds and keeps shutting down.

    When i remove the ATX 12V the comp seems to boot up and stays on, all fans going. So while this happens i plug in the monitor to the graphics card but nothing comes up on screen.

    The monitor light stays orange, it should go green but nothing happens
    Any Solutions?
    Cheers!


    This is whats plugged in

    Specs:

    Intel P4 3.00GHz(Prescott) HT Technology

    Asus P4C800 Deluxe -Ai Series

    EZ Cool - ATX 650JSP 650 Watt Socket 775

    Cosair 1GB XMS PC3200(400MHz)

    Gainward 7800GS+ Bliss 512MB AGP
     
  2. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,915   +167

    You need to replace the power supply
     
  3. AlbertLionheart

    AlbertLionheart TechSpot Chancellor Posts: 2,714

    Either that or you are on my favourite problem - check that you have not got too many motherboard support stubs (little brass things into which you screw the motherboard fixing screws) as an extra one can short out the underneath of the board and produce strange effects. The ultimate check is to run the board outside the chassis.
     
  4. shumon

    shumon TS Rookie Topic Starter

    Thank you guys will give it a try.

    So far i have changed memory around, different slots, different types of ram,
    same thing everytime.

    At the moment the board is in the chassis, screwed down with cpu & heatsink. And the power supply.

    I will try a new Power supply, also will run it outsideof case on a anti static mat.

    Man i really hope its not the cpu or board. Fingers crossed.

    Also will try a different cpu if possible.
     
  5. AlbertLionheart

    AlbertLionheart TechSpot Chancellor Posts: 2,714

    As mentioned, by taking out the board you are bringing it all back to basics. If it works outside the chassis, reconnect things one at a time until you find what is causing the problem.
     
  6. shumon

    shumon TS Rookie Topic Starter

    Hey guys.

    Well i took it out of the case and ran it on the anti static mat.
    No luck it still switches off after 2 seconds. was just running power supply, cpu with heatsink, but everytime i switch it on it cuts off after 2 seconds.

    Next step will be different power supply, but to me the one i have seems fine, but will try anyway. I just really really hope its not cpu.

    Will update this soon.

    Here is whats running -

    - Intel Pentium 4 3.0GHz 800MHz Socket 478 OEM CPU 1MB Cache (Prescott)

    - Asus P4C800 Deluxe

    - EZ Cool - ATX 650JSP 650 Watt Socket 775

    Was just thinking is everything compatible, could there be a compatibility issue?
     
  7. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,915   +167

    Is there thermal paste between the CPU and its heatsink? Are the bios set to failsafe defaults?
     
  8. AlbertLionheart

    AlbertLionheart TechSpot Chancellor Posts: 2,714

    What about the POST beeps? Any at all?
     
  9. shumon

    shumon TS Rookie Topic Starter

    I did put thermal paste between the cpu and heatsink, seems like a normal thin layer, covered all the copper kind of area.

    Nothing has appeared on screen, so no way to get into bios.

    No post beeps.

    i have to pull out the 4 pin ATX 12V cable from motherboard to make the computer run. It stays on but there is no output to the screen.
     
  10. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,915   +167

    The motherboard has to be bad...
     
  11. rascard2007

    rascard2007 TS Rookie Posts: 22

    The CPU also could be the issue try to do a cross check, try ur CPU in another working system and try another known good CPU in urĀ“s.

    If U could borrow or buy a PCI POST Card u can properly identify what component is failing
     
     
  12. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,915   +167

  13. AlbertLionheart

    AlbertLionheart TechSpot Chancellor Posts: 2,714

    Shumon
    Personally I would not spend any more on confirming a bad board. If you are going to replace the board you should also get a new chip and RAM to futureproof the system if you can. I have had a number of these ASUS boards fail so would not be surprised....
     
  14. shumon

    shumon TS Rookie Topic Starter

    Hey guys!!

    Just did a cpu swap and still the same issue. So now i know that the cpu is fine.

    Its the motherboard, it has definatly died. wow cant believe it.

    i usually take care of components carefully - Well i dont think i would buy asus again.

    It was a pretty good board aswell - oh man! anyways im happy my cpu did not fail so next step is to get a 478 board somewhere if places still sell it.

    Thanks guys. Nice advice and definatly on point!! thx again - i love this forum!
     
Topic Status:
Not open for further replies.


Add New Comment

TechSpot Members
Login or sign up for free,
it takes about 30 seconds.
You may also...


Get complete access to the TechSpot community. Join thousands of technology enthusiasts that contribute and share knowledge in our forum. Get a private inbox, upload your own photo gallery and more.