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Building my first PC, no POST. Possibly bad power supply?

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December 12, 2012 1:36:53 PM

My parts:
Graphics: SAPPHIRE Radeon HD 7950 with Boost (11196-16-20G)
Processor: Intel Core i5-3570K
Case: Cooler Master CM690II Advanced
Optical Drive: LG GH-24NS
SSD: Samsung MZ-7PC0128D/EU 830series, SATA 600, MLC-Chips, Black
Motherboard: ASUS P8Z77-V LE PLUS
HDD: Seagate Barracuda ST31000524AS 7200 RPM 3,5 inch SATA
Memory: Corsair 8 GB DDR3-1600 Kit CMZ8GX3M2A1600C9
Cooler: Enermax ETS-T40-TB
Power supply: Corsair CMPSU-750AX

OK, so I started by testing the motherboard, CPU(+cooler), memory, and graphics card on top of the motherboard box. Plugged in the 24 pin and 8 pin (2x4 pins separated connectors) into the motherboard and two PCIe connectors into the graphics card.
When I power it on, the CPU cooler spins but aside from that, nothing works. No beep from the internal speaker, no video, no POST, nothing.

I have tried:

  • Removing every component and putting them back in. I ended up leaving the graphics card out and doing further testing with the onboard graphics.
  • Removing the memory and then placing a single stick in every slot (tried this with both sticks)
  • The (modular) PSU came with two different 8-pin CPU (2x4 pins separated connectors) cables, one cable that plugs into the power supply with an 8 pin connector (labeled CG01) and another one that plugs into the power supply with a 12 pin connector (labeled CH01) of which 4 pins have no wire going into them. I'm pretty sure they're the same cable but I've tried both. The manual is less than one page and it isn't helpful in identifying the cables anyway.

    When I power it on it does the same thing (just CPU cooler spinning) whether or not the 8-pin power connector is plugged in, so I think that's where the problem is, but what do I know.

    Please help. I'm sad.
    a b V Motherboard
    December 12, 2012 2:18:10 PM

    a common mistake for a first time builder is connecting the headers wrong. this is what makes every thing turn on when you push the power button.


    the headers go side ways (the stay in the same row) i would double check the manual on how to connect these correctly
    December 12, 2012 2:33:03 PM

    Make sure you have that little square 4 wire plug plugged in next to the CPU. Also, if the video card takes extra power that you have those plugged in. You can also try removing the video card if the MB has onboard video.
    Related resources
    a b V Motherboard
    December 12, 2012 2:35:35 PM

    scratch that, i missed that part about the fans spinning.
    a b V Motherboard
    December 12, 2012 2:37:31 PM

    so to boot requires 3 basic things
    cpu
    ram
    gpu
    you have already ruled out gpu, so pull all the ram and power on. if you get bios beeps we know its the ram, if not its a cpu issue.
    a b V Motherboard
    December 12, 2012 2:46:28 PM

    that board has memok does the led light up?
    December 12, 2012 2:46:43 PM

    Haven't had a beep (or any video output) under any circumstances, even with a single stick in any of the slots it won't work. After removing both sticks of memory there's still no beep.

    I wonder if it's the CPU power connector. When I power the thing on, only the CPU fan spins. When I remove the CPU power connector, and power it on, still only the CPU fan works. Doesn't seem to matter if that cable is plugged in... It may just as well not be.
    a b V Motherboard
    December 12, 2012 2:56:48 PM

    you will need a multi meter to test the pin out, on the back of the power supply is the switch set to 120 or 240?
    December 12, 2012 3:01:41 PM

    the great randini said:
    that board has memok does the led light up?


    Nope. Don't even see an LED where the diagram in the manual says it should be (there is a MEMOK button there though). That LED must be really tiny.
    December 12, 2012 3:06:01 PM

    the great randini said:
    you will need a multi meter to test the pin out, on the back of the power supply is the switch set to 120 or 240?


    There doesn't seem to be a switch (the manual doesn't mention one either, but then again it doesn't mention much of anything at all). This was bought in Europe, if that matters. Electrical sockets are all 220-240V here.

    I'll see if i can't get a multimeter somewhere...
    December 12, 2012 3:11:13 PM

    Right have a look on the motherboard where the model number is printed on the board, next to it should be the bios revision of the board, or it will be found near the bios chip.
    You need a bios revision of 0516 to run the board with the Cpu, anything lower and the board will not post.
    December 12, 2012 3:37:12 PM

    I don't think I can do this... All the wires are black.
    December 12, 2012 3:44:08 PM

    weaselman said:
    Right have a look on the motherboard where the model number is printed on the board, next to it should be the bios revision of the board, or it will be found near the bios chip.
    You need a bios revision of 0516 to run the board with the Cpu, anything lower and the board will not post.


    It says "rev 1.01" and the manual says it supports 3rd generation i5 processors.
    December 12, 2012 4:18:32 PM

    I've got a multimeter but I just can't figure out how to test it. It's hard to google something when I don't know how to phrase it. Can anyone help point me in the right direction?
    a b V Motherboard
    December 12, 2012 4:57:38 PM

    farigiss said:
    I've got a multimeter but I just can't figure out how to test it. It's hard to google something when I don't know how to phrase it. Can anyone help point me in the right direction?


    All ATX Power supplies use the same pinout.

    http://pinouts.ru/Power/atxpower_pinout.shtml
    !