New Build Powerup Problem (NEED HELP)

By meoakleaf ยท 4 replies
Dec 2, 2005
  1. I'm sending out an SOS to all the expert computer builders out there. I just finished building my first ever computer from scratch. I've fiddled around before with new memory, graphics cards, sounds cards, and power supplies, but this is my first ever new build everything from scratch assembly.

    Problem is, it doesn't work! When I hit the power button, all the fans turn on, my LEDs come on, but only for half a second and then they turn right back off. I've read through several posts that say to removed the motherboard to eliminate possible shorting, but that didn't help. I've checked the seating and reseated all my components. I verified that the CPU has no bent leads, and that the heatsink is mounted properly. I reset the BIOS and removed the battery for 20 min. I removed all but the bare essentials, did an out of box powerup using screwdriver to short power up pins, and nothing changes. Same half sec power on then off.

    Here's what I'm trying to build:
    nForce3-A Motherboard
    nVIDIA NF3 250 chipset
    AMD Sempron 2800+ CPU
    Kingston KVR400 512MB
    RAIDMAX Scorpio case with 420W pwr supply
    ATI RADEON x700 PRO AGP 256MB Graphics Card

    I have no idea what to do next. Seems similar to the CPU overheating auto shut off problem that I've read about in other threads, but I don't know why my build would be doing that. I don't know if I need to do something different or return something. Is the CPU bad, is the motherboard bad, is the power supply bad, is the case wiring bad, do I have bad jumper settings? Is there a guru out there that can help me?

  2. zephead

    zephead TechSpot Paladin Posts: 1,569

    it sounds like you've already been over every square inch of the system...perhaps you should have it looked at by a technician.
  3. mailpup

    mailpup TS Special Forces Posts: 7,186   +469

    I could be wrong but the power supply that came with the case has my vote as most suspect.
  4. patio

    patio TS Guru Posts: 482

    Double check that your RAM is matched for that MBoard otherwise i would tend to agree with mailpup as to a bad/underpowered PSU.
    When you did the bench test what components did you hook up ? ?
    It should be only RAM, CPU, and vid card...

    patio. :cool:
  5. meoakleaf

    meoakleaf TS Rookie Topic Starter


    You guys are awesome!!! I am now up and running. I tried an different power supply and I'm good to go. Looks like the problem had to do with the type of connector on the power supply that came with the case. There was an oversized latch that was hitting a poorly placed capacitor that must have been preventing complete connectivity.

    Unfortunately the new power supply with the smaller latch is only 250W whereas the one with the larger latch was 420W. Still I'm loading windows now so it must have enough juice.

    Thank you guys so much! :)
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