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Motherboard won't turn power supply on.

By JLCicchino ·
My thanks, in advance, for anyone who can help me.
I recently built a system with all new components. When finished, and plugged in/turned on, there was no power to the system (at all). No LEDs lit, no fans turning, no drives spinning, no beeps .. . nothing. I originally suspected a faulty power supply because even the power supply's fan wasn't working. Plus, I checked the wires from the supply with a voltmeter, and there was no voltage (power).
I installed my old power supply in the new system with the same results, no power. However, both power supplies work in my old system when attached to the motherboard via the ATX connector. As long as the 2 small wires from the power-on switch (case front) are attached to the motherboard, and the power supply ATX connecter is attached to the motherboard, the power supply will turn on. Apparently, the power switch on the case front sends a signal to the motherboard, through the ATX connector (wires), and tells the power supply toturn on.
I have tried the power switch wires in both possible +/- orientations on the PW-ON pins of the board. I even tried to check the power-on switch by briefly "shorting" the 2 pins labelled PW-ON with a screwdriver, but this did nothing. I have an AthlonXP1700 which runs at 1466MHz so my board settings are: 133MHz(clock) x 11(multiplier) = 1463MHz. The core voltage is set to "Auto" but I also tried 17.5V. The RAM voltage is set to 2.5V (default). There is 128MB PC2100 in bank 0/1.
I was meticulous in assembling the system, particularly with respect to grounding myself. There is no way there could have been static damage to the board. I've done this twice before with no problems.
If someone knows how I can getmy motherboard (Epox:EP-8KHAL) to turn on the power supply, I would GREATLY appreciate it. Thanks.

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Been There

by r_niswonger In reply to Motherboard won't turn po ...


I have run into the same situations while rebuilding / building my own systems. What I have found deals with memory. If the Bus speeds are wrong, or mismatched, you will not get power to the power supply. Also if the memory is bad or one of the chips on the memory are bad you will not get power to the power supply.

I have foun, by chaning the memory modules, I have gotten power. You might give that a try...hopefully it will work for ya.

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