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Power Supply Wont Power up - Gigabyte ga-ma790fx & AMD Phenom 9850

By irishbloke
Sep 10, 2008
  1. Ever since i got this new motherboard and CPU ive been having a bit of a nightmare with it.

    Gigabyte ga-ma790fx-ds5 -Latest Bios
    AMD Phenom Black Edition 9850,
    4 gigs PC 6400 ram (Corsair XMS2 CM2X1024-6400
    ATI Radeon 4870

    The problem is that the motherboard will NOT power up at all with the 2 of the latest power supplies (600 watt+) i have.

    It wont work at all with; (Nothing happens its just dead)
    Arctic 600 watt Jeantech PSU (brand new and working)
    Corsair 620 watt HX PSU (working)


    It only seems to work with my Jeantech 450 Watt PSU and i cant for the life of me figure out why. Ive tried everything to get the board to work with the new PSU's. I had thought that the PSUs i got were dodgy but after testing out one in an older PC it worked fine.

    Ive removed all parts and tried powering up and i cant get it to boot up. But the PC seems to work fine with the oldish 450 watt PSU which i find just unbelievable.

    Can anyone help with this nightmare? Now on the Gigabyte site the CPU i have isnt listed as supported by this motherboard which is kinda worrying could this be the reason? If so how the old PSU boots up.

    I just want to have the fracking thing working with the right PSU.
     
  2. DaMak420

    DaMak420 TS Rookie Posts: 189

    if I read the specifications right on your mobo... it implies that it has the 4 pin PCI-e input(power) but it also has the 8pin ATX power conector. (it may be simply removing a cap that is actually right next to the 4 pin connector, thus making it an 8 pin connector (thats how it was on my mobo)

    Try using the 8pin power with your new PSU, see if that works.
     
  3. nickc

    nickc TechSpot Paladin Posts: 923   +11

  4. irishbloke

    irishbloke TS Rookie Topic Starter

    thanks for the quick replies folks:)

    Ive tried that many times with 2 different Power supplies:(
    Ive tried it with the 4 and then 8 etc over and over and nothing.

    I think the only thing i can do now is try my old AMD 6000 CPU in the mobo and rule the mobo out and rule a CPU & MOBO conflict.

    This problem is driving me nuts to be honest, paid a lot for this board it was suppose to support AM2+ but it doesnt seem to support the chip i have for it.

    There is another thing the PSU i have is well faulty. i.e it powers the motherboard on into a kinda standoff state until i press the power button on the case. So its like just auto powering the board without i guess the usually "checks" a mobo does. Could this be the reason the mobo power ups. And i know this isnt a good situation which i why i need a decent PSU connected.

    The official response from Gigabyte wasnt much help;

     
  5. irishbloke

    irishbloke TS Rookie Topic Starter

    Just an update;

    Tried an old AMd 6000 chip and the motherboard still failed to boot. Tried 3 different power supplies, 4pin and 8pin CPU 12v and still it failed to power up on the 600watt PSU's which are working fine.

    so im guessing its a dodgy motherboard. im gonna get it returned and RMA the board.

    What do you folks think?
     
  6. DaMak420

    DaMak420 TS Rookie Posts: 189

    sounds like a plan!
     
  7. nickc

    nickc TechSpot Paladin Posts: 923   +11

    Gigabyte has been bad about that kind of stuff lately, and there support has been lousy.
     
  8. irishbloke

    irishbloke TS Rookie Topic Starter

    My previous board was an Asus and they seemed not quite good either but the board was reasonably solid except it lacked AM2+ support.

    There is another thing the PSU i have is well faulty. i.e it powers the motherboard on into a kinda standoff state until i press the power button on the case. So its like just auto powering the board without i guess the usually "checks" a mobo does. Could this be the reason the mobo power ups. And i know this isnt a good situation which i why i need a decent PSU connected.

    I just cant understand why the old PSU works but the new ones dont? any ideas?
     
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