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4 pin ATX 12V Power supply problem

By 99Jones99 · 11 replies
Sep 4, 2007
  1. I sure hope you guys can help me.

    I have just had my first go at building a PC to be used as a media centre. The spec is as follows:

    Motherboard = Gigabyte GA-9859-DS39
    Processor = Intel Core 2 Duo E6750 (2.66Ghz, 4MB L2 Cache, 1333Mhz FSB)
    Memory = 2Gb Kingston PC2-800 CL5 DIMM (KVR800D2N5K2/2G)
    Graphics card = Leadtek PX8600 GT THD

    I got it all set up, plugged in the power. It whirred (ie, fans started) and then within two seconds there were four short beeps followed by power down. It then powered up and repeated, and repeated this.

    Nothing was displayed on the monitor.

    According to the manual “continuous beeps” is “power error”.

    I pulled everything off the motherboard, except the CPU and cooler. Same problem.

    I unplugged the 4 pin ATX 12V power connector. Fans now power up and keep going!

    I purchased a new power supply and the situation is repeated.

    So, I can get power to the motherboard but not to the CPU via the 4 pin plug. My reading of posts to this forum (and other forums) is that the 4 pin 12 volt plug is required for the system to operate.

    Any clues?

    One thought that I had was that the processor cooler was not property seated as I had not had the same difficulty as others had had in installing it. Could this be the problem?

  2. Rik

    Rik Banned Posts: 3,679

    Try clearing the cmos, your mobo manual will tell you how to do it.
  3. mailpup

    mailpup TS Special Forces Posts: 7,359   +603

    I too don't think you listed the correct model number. I couldn't find it either.

    Is there any chance you mixed up the 4 pin ATX 12V connector with the 4 pin connector from the 20 + 4 pin power supply to main motherboard connector? Those 4 pin connectors are not interchangeable.
  4. 99Jones99

    99Jones99 TS Rookie Topic Starter

  5. 99Jones99

    99Jones99 TS Rookie Topic Starter

    The original PSU came with the case (Antec NSK4400). The replacement is a CoolMaster RS-430-PCAR http://umart.net/au/product_info.ph...1365&osCsid=3d0ce86f3a431ac8074d644cc021b213). I am assuming it is unlikely that both PSUs would have the same failure (I don't feel like buying a third one!).

    The beeps are 4 short beeps that occur about 1-2 second after the power button is swithched on. As I said, it then spools down (fans stop) and then cycles on again. I assume it would keep doing this forever, but I switch it off after 3-4 cycles.
  6. mailpup

    mailpup TS Special Forces Posts: 7,359   +603

    Could you try leaving in just one RAM module, testing and then swap with the other and test again?
  7. 99Jones99

    99Jones99 TS Rookie Topic Starter

    At the moment I have no memory in (only CPU and cooler). I will try with memory in but am not sure what this is expected to achieve.

    Regarding "well could be the mob", I was hoping no one would say that!
  8. 99Jones99

    99Jones99 TS Rookie Topic Starter

    The connector is 20 pin and 4 pin.

    Will try without the dedicated 12v CPU. Should it work?
  9. 99Jones99

    99Jones99 TS Rookie Topic Starter

    OK. Cleared CMOS, put in memory, HDD, graphics card, plugged in 24 pin power (12V1), removed 4 pin CPU power (12V2), and press the power button.

    Fans spooled up, but no beeps, nothing on the monitor - just fans!

    I don't know if it is relevant, but CPU cooler fan starts, stops and the starts and keeps going, where as the fan in the PC case starts and keeps going.

    Any more suggestions?
  10. 99Jones99

    99Jones99 TS Rookie Topic Starter

    Hi Codex Computing. On the advise of the shop where I bought the all of the stuff I have removed the mobo from the case, disconnected everything except the CPU and speaker, plugged in the 24 pin plug (12V1) and 4 pin plug (12V2) and shorted the power jumpers. Situation is same as when in the case fans spool up, beeps, fans spool up, beets etc. Shop owner advised me to return the mobo as probably is faulty. I have my fingers crossed!! Will keep you posted. Regards and thanks.
  11. shumon

    shumon TS Rookie

    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?

    This is whats plugged in


    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

    Any Solutions?
  12. 99Jones99

    99Jones99 TS Rookie Topic Starter

    Hi Codex Computing. I'm in Australia. Laws will be similar. Thanks.

    shumon. Sorry to hear of your (similar) problem. I will be returning my mobo to where I bought it. If I can shed any light on the problem I will do so.
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